C4 K2 finds
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The K2 C4 lightcurves are now online, thanks to Al Schmitt (HEK) for providing us with the long cadence PDCSAP_FLUX lightcurves for LcViewer.
Apparent glitches (Midpt Time):
2238.65 BKJD
2271.76 BKJD
2287.5 BKJD
Planet Candidates (Transits):
ID 210326405 (later check)
ID 210331473 (later check)
ID 210364628 (2262.14 BKJD) Unsure
ID 210365511 (P = 3.952) possible cont.
ID 210372242 (P = 32.824) Unsure
ID 210388679 (2263.39 BKJD) Unsure
ID 210389383 (P = 14.07) Maybe additional periodic signal
ID 210395468 (2259.53 BKJD) Unsure
ID 210400897 (later check)
ID 210402237 (P = 10.996)
ID 210448729 (later check)
ID 210525500 (P = 1.369) probably cont.
ID 210558622 (P = 19.564)
ID 210568002 (P = 1.522) probably cont.
ID 210577548 (P = 6.419)
ID 210609658 (P = 14.113)
ID 210626797 (probably cont.)
Eclipsing Binary Candidates:
ID 210316476
ID 210321339
ID 210327060
ID 210329155
ID 210341949
ID 210348130
ID 210350446
ID 210354201
ID 210355269
ID 210355311
ID 210356450
ID 210360901
ID 210361551
ID 210361885
ID 210362393
ID 210367220
ID 210367469
ID 210370729
ID 210372930
ID 210373111
ID 210375290
ID 210376318
ID 210376335
ID 210378102
ID 210379010
ID 210385468
ID 210385758
ID 210386880
ID 210386883
ID 210387836
ID 210388603
ID 210391114
ID 210397036
ID 210401157
ID 210403086
ID 210404228
ID 210408447
ID 210411757
ID 210412074
ID 210413481
ID 210414957
ID 210421801
ID 210426077
ID 210426551
ID 210427081
ID 210433146
ID 210434247
ID 210437218
ID 210437941
ID 210438688
ID 210447939
ID 210451200
ID 210453345
ID 210454588
ID 210454657
ID 210464181
ID 210464781
ID 210467408
ID 210470747
ID 210471407
ID 210471954
ID 210472483
ID 210474285
ID 210475773
ID 210476794
ID 210484192
ID 210489231
ID 210492153
ID 210493551
ID 210495899
ID 210501149
ID 210512162
ID 210513446
ID 210522228
ID 210530173
ID 210538996
ID 210555161
ID 210562330
ID 210568214
ID 210572738
ID 210574135
ID 210574837
ID 210576234
ID 210577546
ID 210581202
ID 210586972
ID 210589188
ID 210589260
ID 210591703
ID 210593417
ID 210598340
ID 210604953
ID 210609071
ID 210619926
ID 210622523
HB:
ID 210433394 (Looks nice!)
DSCT/GDOR:
ID 210318134
ID 210344373
ID 210344532
ID 210348175
ID 210354975
ID 210364509
ID 210373873
ID 210374056
ID 210375765
ID 210376377
ID 210384744
ID 210390571
ID 210395925
ID 210408934
ID 210413734
ID 210421204
ID 210424124
ID 210427204
ID 210429154
ID 210437575
ID 210438520
ID 210441967
ID 210449987
ID 210460860
ID 210462235
ID 210468979
ID 210471690
ID 210491773
ID 210498388
ID 210516402
ID 210517217
ID 210529209
ID 210530626
ID 210544036
ID 210568531
ID 210586179
ID 210596089
ID 210608585
CV/DN/LPV:
ID 210332154
RR-Lyrae Type:
ID 210311535
ID 210322126
ID 210343581
ID 210345648
ID 210389601
ID 210394470
ID 210399040
ID 210418729
ID 210454384
ID 210457607
ID 210471429
ID 210475866
ID 210507908
ID 210509604
ID 210511418
ID 210577318
ID 210607917
ID 210617106
Asteroids encounters
ID 210307221
ID 210309341
ID 210312511
ID 210322477
ID 210325299
ID 210328701
ID 210329073
ID 210352551
ID 210365226
ID 210395925
ID 210419493
ID 210420672
ID 210426073 (Numerous)
ID 210428894 (Numerous)
ID 210432795
ID 210434976
ID 210437334
ID 210454684
ID 210459199
ID 210469180
ID 210478124
ID 210483775
ID 210485181
ID 210489346
ID 210501536
ID 210503612
ID 210506844
ID 210553950
ID 210569604
ID 210575024
ID 210593490
ID 210601109
ID 210604966
Others:
ID 210352799
ID 210398323
ID 210480960
ID 210494515 (check out later)
ID 210553798
ID 210600482
ID 210614304
Posted
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by Shellface
Cripes, that's quick. No time to stall in this business, eh.
The campaign 4 field lies towards the centre of Taurus. If you know much about the constellation, then you'd know that two of the brightest and most important open clusters in the sky - the Hyades and Pleiades - lie over here, and you'd be right (see figure). As they are so important, many of the cluster stars have been studied fairly intensively for binaries, so I would recommend cross-checking with SIMBAD and other references. However, planetary transit searches in the area have been highly limited, so there's a lot of potential for new discoveries.
Cluster members are well demarcated towards the edges of the field, and identifying those of interest should be a priority. Still, everything the photometry can tell about the cluster members is useful, because they're important benchmark stars in the <1 Gyr region (~900 and 120 Myr old, respectively). Planet hosts are only the foremost of these.
Reddening in this field is somewhat varied - open space and the Hyades are somewhat modestly reddened, but the Pleiades are more strongly reddened because they are more distant and because the cluster is passing through a dust cloud.
Anyway - if fortune is with us, this will be a very interesting field. If so, it could perhaps only be dethroned by campaign 5…
Posted
-
by zoo3hans
Planet Candidates (Transits):
ID 210400751 Period about 16.02 days. Depth about 0.00025. At 2257.34, 2273.36, 2289.38.
ID 210629082 Period about 27.3 days. Depth about 0.00045.
ID 210731500 Period about 9.7275 days. At 2229.6, 2239.3, 2248.99, 2258.76, 2268.49, 2278.22, 2287.93, 2297.66.
ID 210744272 Period about 22.8 days. At 2250.62, 2273.42, 2296.22. Depth 0.004.
ID 210750726 Period about 4.6 days. Depth about 0.002.
ID 210754505 Period about 0.87 days.
ID 210769880 Period about 1.437 days. At 2229.6 etc.
ID 210774732 Maybe single transit/eclipse at 2248.17.
(Also bad cases (with a period around 11.41 days): ID 210774836 and ID 210774814 and ID 210771577 and 210750182 and 210735322 and 210731902.)
ID 210777017 Period about 11.382 days. At 2237.34, 2248.70, etc. Depth about 0.001.
(ID 210779624 Period about 5.705 days. This the same as below with other cases. Also we have alternating spacings. Probably another bad case of contamination. Sigh)
ID 210780851 Period about 15.7825 days. It looks like a Warm Jupiter. Transit depth about 0.017. Nice U-shape.
ID 210786627 Period about 1.72 days. For example at 2239.2, 2240.9, 2242.65, 2244.38, etc.
(ID 21790246 Period about 11.405 days. Maybe BGEB like the others.)
(ID 210814892 Period about 11.4 days. Maybe BGEB like the others.)
ID 210819089 Maybe huge TTV's. Period about 17.3167 days.
ID 210825751 Maybe single transit at 2275.95. Depth about 0.009.
(ID 210829981 Period about 11.41 days. Hm, maybe BGEB like the others with this period.)
ID 210836070 Maybe Multi.
(ID 210837083 Maybe Multi. One period 11.4 days (starting at 2239.22). But could also be contamination by a BGEB of course.)
(ID 210842555 Period about 5.703 days. Hey, this is practically the same as the candidate below, so maybe both are just contamination. Sigh.)
(ID 210845609 Period about 5.705 days.)
ID 210848071 Period maybe 41.72 days. At 2235.52 and 2277.24. Depth 0.0006.
(ID 210854497 Period about 11.405 days. At 2239.21 etc.)
(ID 210869095 Period about 11.41 (5.199 days or 6.30 apart), so maybe BGEB.)
ID 210892669 Period about 5.649 days. Depth 0.0012. Rather V-shaped though.
ID 210956385 Maybe transit at 2232.4 and a possible repeat at 2289.07. Period would be 56.655 days. Depth about 0.008.
ID 210957318 Period about 4.0987 days. Depth 0.016. Nice Hot Jupiter.
ID 210961508 Period about 0.3498 days. Starting at 2229.1.
ID 210966398 Maybe single long transit at 2271.6 (although Martti mentioned a glitch very nearby).
ID 210968143 Period about 13.74 days. At 2231.91, 2245.65, 2259.39, 2273.13, 2286.87. Depth 0.0017.
ID 211002562 Period about 3.347 days. Nice Hot Jupiter. Depth 0.017.
ID 211010922 Period about 40.7 days. At 2248.6, 2289.3. Depth 0.02.
ID 211021753 Good dip at 2271.5.
ID 211027550 Good dip at 2254.5. But could be a glitch. I see a similar dip with ID 210974434.
ID 211041648 Maybe transits at 2248.2, 2275.2. Possible period around 27 days.
ID 211051439 Maybe single transit at 2238.7.
ID 211087003 Period about 28.3 days. At BKJD 2287.7, 2259.45, 2231.15 (depth 0.0015, duration 4.5 hours). Another larger transit at 2251 (depth 0.0079, duration 7 hours).
ID 211089792 Period about 3.259 days. Maybe Hot Jupiter, depth about 0.025.
ID 211099781 Period about 7.564 days. Nice Hot Jupiter.
ID 211133138 Period about 7.435 days. For example at 2238.17, 2245.6, etc.
ID 211147528 Period about 2.3485 days.
ID 211169300 Period about 16.45 days. At 2234.8, 2251.25, 2267.7, 2284.15.
Eclipsing Binary Candidates:
ID 210626797
ID 210634139
ID 210642322
ID 210650657
ID 210654881 Nice eccentrical EB
ID 210657179 Maybe contamination, depth is rather small.
ID 210663545
ID 210664740
ID 210668314
ID 210675130
ID 210692406
ID 210725198 Nice LC. Primary at 2258.18, secondary at 2234.74.
ID 210734262
ID 210734337
ID 210740200
ID 210742688
ID 210744182
ID 210744674 Period about 25.2 days. Depth 0.035.
ID 210749423
ID 210750052
ID 210754756
ID 210760314 Single eclipse at 2248.15.
ID 210766835
ID 210779706 Maybe period about 31.46 days.
ID 210784039
ID 210786891
ID 210789323 Eclipse at 2240.72.
ID 210793743
ID 210801596
ID 210805120
ID 210821360
ID 210822691
ID 210823406 Single eclipse at 2257.35.
ID 210832801 Very different sized stars.
ID 210835735
ID 210837460
ID 210838192
ID 210841030 Period about 10.36 days. The dips have alternating spacings, so probably BGEB.
ID 210843343 Period about 11.405. Maybe contamination by BGEB.
ID 210846734
ID 210857749 Only one eclipse, but an obvious one.
ID 210863062
ID 210865148 Interesting pattern (i.e. tertiary system).
ID 210876158
ID 210879084
ID 210903662 Period about 2.43 days, Depth only 0.0056. So maybe it could also be a Hot Jupiter.
ID 210912231
ID 210925707
ID 210935498
ID 210941737
ID 210945342
ID 210954859
ID 210958990 Period about 1.7022 days. Depth 0.023. Probably an EB because I see small secondaries.
ID 210960936
ID 210961385
ID 210965791
ID 210969614
ID 210974364 Period about 34.75 days.
ID 210991175 Period about 6.8589 days. Small secondaries are visible between the V-shaped large dips.
ID 210991175
ID 211000135
ID 211009047
ID 211012889 (maybe contamination)
ID 211013604
ID 211014765
ID 211015722
ID 211017994
ID 211019860
ID 211020446
ID 211036449
ID 211041532
ID 211064647 Eclipse at 2273.97. V-shaped. Could be a PC nevertheless. Depth 0.015.
ID 211064990
ID 211066849
ID 211075893 Eclipse at 2253.76.
ID 211075914 Eclipse at 2266.22, probably secondary eclipse at 2237.14 and 2279.93, possible period 42.79 days.
ID 211082420 nice
ID 211093684
ID 211096084
ID 211110438
ID 211132787
ID 211135350
ID 211143504
ID 211147178
ID 211154046
ID 211155479
ID 211155977
ID 211158357
ID 211160700
ID 211160717
ID 211179336 short period EB or pulsating (shutter effect)
ID 211179955
ID 211182027 nice semi-detached EB
DSCT/GDOR:
ID 210672179 D
ID 210747473 D
ID 210752606 D
ID 210762209 G
ID 210794599 D
ID 210814048 D
ID 210845303 D
ID 210850601 D
ID 210857465 D
ID 210999011 D
ID 211016408 D
ID 211020068 G
ID 211022330 D
ID 211023010 D
ID 211028830 G
ID 211044267 D
ID 211046195 D
ID 211046293 D
ID 211053882 D
ID 211079163 D
ID 211083629 D
ID 211083721 D
ID 211086170 D
ID 211089419 D (or regular periodic variable)
ID 211093928 D
ID 211104058 D
ID 211109330 D
ID 211115338 D
ID 211118985 D
ID 211150258 D
ID 211161825 G
ID 211173015 D
ID 211178965 D
ID 211193773 G
RR-Lyrae Type:
ID 210678680
ID 210681941
ID 210697426
ID 210729707
ID 210733035
ID 210754711
ID 210763406
ID 210766289
ID 210815465
ID 210830646
ID 210839363
ID 210868876
ID 210925792
ID 210994946
ID 211010071
ID 211048310
ID 211069540
ID 211069629
ID 220115899
ID 220115902
ID 220115904
ID 220115915
ID 220115916
ID 220115917
ID 220115935
ID 220115936
ID 220115942
ID 220115946
ID 220115949
ID 220115951
ID 220115952
ID 220115954
ID 220115955
ID 220115959
ID 220115960
ID 220115962
ID 220115969
ID 220115970 (contamination?)
ID 220115973
Asteroids encounters:
ID 210696380 at 2240.71 Erfjord
ID 210747818 at 2250.58 Kythera
ID 210748446 at 2246.76 Pandarus (Trojan)
ID 210761838 at 2268.275 Kythera
ID 210781898 at 2241.47 Wanda
ID 210786719 at 2263.35 Wanda
ID 210787202 at 2237.47 Wanda
ID 210840966 at 2255.14 Onizaki
ID 210905854 at 2235.48 Lindelof
ID 210963351 at 2243.2 Brian
ID 211107439 at 2297.47 Flare?
ID 211110493 at 2261.96 1999 HN7
ID 211194832 at 2264.4 Aglaja
Others:
ID 210662654 Maybe DN
ID 211068547 funny LC (pulsating)
ID 211081096 Maybe short period Cepheid. Period about 5.113 days.
ID 211103863 Maybe short period Cepheid. Period about 6.154 days.
ID 211106023 Maybe short period Cepheid. Period about 3.7233 days.
ID 220115897 at 2264.1 maybe DN
ID 220115908 at 2294.25 maybe DN
ID 220115910 at 2291.8 maybe DN
ID 220115958 at 2254.2 DN (Dwarf Novae)
Maybe glitches:
BKJD 2239.21
BKJD 2250.61
BKJD 2296.25
(The EB and DSCT and Asteroid lists are not complete, I list only obvious cases)
Posted
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by JKD
ID 210626797 already mentioned, however it might be a 2 planet candidate
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at 2239.567 BKJD, p~ 43.377 d
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at 2265.066 BKJD
Posted
-
-
by ajamyajax
211002562: so our interesting planet hunting work continues with C4 data! As Hans Martin indicated with his findings, a nice hot Jupiter makes sense here. But with sparse data, a little more guesswork is also required for the transit duration and stellar estimates. A smaller star seems to work with the colors while a larger estimate fits better. But they are all still hot Jupiters in radii anyway. And TTV is possible also but not certain. Also noting this transit another one of those that seems related to the stellar cycle.
s1=2229.11 p1=3.3475 d1=0.133 (3.20 hours +/-)
ttv1= [2229.117,2232.447,2235.808,2239.1485,2242.498,2245.841,2249.192,2252.553,2255.88,2259.234,2262.584,2265.934,2269.286,2272.636,2275.987,2279.3295,2282.677,2286.019,2289.361,2292.7195,2296.061,2299.413]
ttv1_gaps = [2235.808,2292.7195]
EPIC, 2MASS, J mag, H mag, K mag, J - H, H - K, (J-H spectral type, stellar mass est) (H-K spectral type, stellar mass est)
211002562 , 2MASS J03285136+2300557 , 11.241 , 10.891 , 10.795 , 0.35 , 0.096 , ('G8V', 0.94) , ('K1V', 0.86)
au min-max 0.045 0.05
stellar diameter in solar units min-max 1.19 1.36
stellar mass in solar units min-max 1.085 1.49
period in days min-max 3.345 3.351
duration in hours min-max 3.151 3.244Posted
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by ajamyajax in response to JKD's comment.
210626797: ok, three obvious transits to work with here. The first and third transits (a half transit actually) seem to be about the same shape and depth. And their fit is fairly stellar as shown here. The middle transit's depth is less than the others and is more planetary in shape which is good. So since all transits seem to be at planetary depth, two PC's are certainly possible. But there is also a chance of a blended eccentric binary here.
s1=2239.568 p1=43.35 d1=0.25 (6.0 hours +/-)
s2=2265.067 p2=? d2=0.21 (5.04 hours +/-)
EPIC, 2MASS, J mag, H mag, K mag, J - H, H - K, (J-H spectral type, stellar mass est) (H-K spectral type, stellar mass est)
210626797 , 2MASS J03371078+1720341 , 11.707 , 11.434 , 11.390 , 0.273 , 0.044 , ('G2V', 1.0) , ('A9V', 1.66)
Posted
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by ajamyajax
211099781: another hot Jupiter candidate per Hans Martin. My program ranges vary with this data, so going with the smaller color estimate in the chart which uses a 0.96X R_sol star.
s1=2231.475 p1=7.5643 d1=0.233 (5.6 hours +/-)
EPIC, 2MASS, J mag, H mag, K mag, J - H, H - K, (J-H spectral type, stellar mass est) (H-K spectral type, stellar mass est)
211099781 , 2MASS J03441296+2433266 , 10.797 , 10.485 , 10.395 , 0.312 , 0.09 , ('G6V', 0.97) , ('G9V', 0.91)
au min-max 0.07 0.09
stellar diameter in solar units min-max 1.045 1.85
stellar mass in solar units min-max 0.8 1.705
period in days min-max 7.553 7.578
duration in hours min-max 4.002 5.863Posted
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by ajamyajax
210389383: this find by Martti could also be a hot Jupiter, but since the transit depth is ~2.8x% the star would need to be on the small side here. I didn't see the additional signal mentioned but didn't look too closely for that yet.
s1=2236.77 p1=14.087 d1=0.20 (4.8 hours or more)
EPIC, 2MASS, J mag, H mag, K mag, J - H, H - K, (J-H spectral type, stellar mass est) (H-K spectral type, stellar mass est)
210389383 , 2MASS J04102487+1313037 , 11.257 , 10.905 , 10.772 , 0.352 , 0.133 , ('G8V', 0.94) , ('K6V', 0.7)
au min-max 0.11 0.14
stellar diameter in solar units min-max 1.01 1.7
stellar mass in solar units min-max 0.895 1.845
period in days min-max 14.083 14.096
duration in hours min-max 4.603 6.098Posted
-
by troyw
I think 210389383 has a secondary eclipse and is on an eccentric orbit.
Posted
-
by troyw
211002562 also has a secondary eclipse and has no eccentricity.
Posted
-
by ajamyajax in response to troyw's comment.
Agreed: 211002562 and 210389383 both show signs of blended secondary transits. 211002562 stronger than 210389383, but still very possible. So my HJ optimism for both was (edit: or could have been) premature. Thanks for helping with this and hope to see you contributing more often (when you have the time).
Edit: there is still a chance the secondary is an albedo effect from a luminous HJ being eclipsed.
Posted
-
by JKD
KID 210725198 - EB
S1 at 2234.736, transit time ~16.18 hrs, Flux ~9100 ppm
S2 at 2258.141, transit time ~18.63 hrs, Flux ~103277 ppm
Posted
-
by JKD
KID 210744674 - pot. PC
S at 2232.917 BKJD
transit duration ~3.43 hrs
Flux ~33769 ppm
Posted
-
by JKD
KID 210685585 - pot PC
S at ~2283.679 BKJD
transit duration ~7.84 hrs
Flux ~21468 ppm
Posted
-
by JKD
KID 210709659 - interesting, very symmetric LC when eliminating some dots
(a speculative Ring-Candidate)S at ~2294.988 BKJD
transit duration ~23.537 hrs
Posted
-
by ajamyajax
210402237: has potential as a sub-Neptune using ~ 0.91X R_sol star for the radii estimate shown. The stellar estimates I get are also fairly consistent here.
s1=2237.24 p1=11.0 d1=0.15 (3.6 hours)
EPIC, 2MASS, J mag, H mag, K mag, J - H, H - K, (J-H spectral type, stellar mass est) (H-K spectral type, stellar mass est)
210402237 , 2MASS J03410141+1331098 , 10.358 , 9.998 , 9.907 , 0.36 , 0.091 , ('G8V', 0.94) , ('G9V', 0.91)
au min-max 0.08 0.1
stellar diameter in solar units min-max 0.73 0.945
stellar mass in solar units min-max 0.565 1.105
period in days min-max 10.988 11.013
duration in hours min-max 3.559 3.696Posted
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by ajamyajax
210558622: another sub-Neptune candidate that seems to have consistent stellar parameters, and a star ~0.7X R_sol. Also maybe a ring or exomoon candidate with possible transit duration variations (TDV), although sparse or even blended data is another possible explanation.
s1=2231.192 p1=19.584 d1=0.155 (3.72 hours)
EPIC, 2MASS, J mag, H mag, K mag, J - H, H - K, (J-H spectral type, stellar mass est) (H-K spectral type, stellar mass est)
210558622 , 2MASS J04031027+1620509 , 10.231 , 9.649 , 9.496 , 0.582 , 0.153 , ('K5V', 0.75) , ('K6V', 0.7)
au min-max 0.115 0.13
stellar diameter in solar units min-max 0.595 0.705
stellar mass in solar units min-max 0.53 0.765
period in days min-max 19.566 19.575
duration in hours min-max 3.603 3.79Posted
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by JKD
210750182 - PC with 6 repeats, p=11.4d, starting at ~2239.2 BKJD
Posted
-
by JKD
210760314 - an EB signature (already mentioned on page 1; some details below)
S at ~2248.17 BKJD, td ~9.8 hrs, dFlux ~221289 ppm
Posted
-
by zoo3hans in response to JKD's comment.
Dear JKD
regarding EPIC 210750182 : see my post on page 1, there are several cases with the same period - it must be some kind of contamination. I also noticed that it shows 2 dips spaced 5.x and 6.x days in between the 11.405 period or so in these cases. It seems that there is an eccentical EB somewhere in the field.
Posted
-
by JKD
210766835 - interesting EB with p~24.78 d
however transit duration and dFlux are varying significantly
maybe there is a 3rd object around
Posted
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by JKD in response to zoo3hans's comment.
Hello zoo3hans,
my search function was obviously not able to find your comment
In the meantime I was successfulBR
HansPosted
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by JKD in response to zoo3hans's comment.
210775710 - PC
p~59.876d
starting at ~2291.556 BKJD
transit duration ~6.37 hrs
dFlux ~12074 ppm
Posted
-
by JKD
210789323 - likely a PC with p~29.1 d at 2240.72 BKJD (see also page 1)
Posted
-
by ajamyajax
210577548: possible super-Earth MPC with a stellar radii ~= 0.73X R_sol. And there could be another PC here too, but all this needs to be checked later with more corrected data.
s1=2232.00 p1=6.421 d1=0.105 (2.52 hours)
s2=2235.59 p2=27.867 d2=0.17 (4.08 hours)
EPIC, 2MASS, J mag, H mag, K mag, J - H, H - K, (J-H spectral type, stellar mass est) (H-K spectral type, stellar mass est)
210577548 , 2MASS J03431422+1638044 , 11.613 , 11.206 , 11.059 , 0.407 , 0.147 , ('K2V', 0.85) , ('K5V', 0.75)
au min-max 0.055 0.065
stellar diameter in solar units min-max 0.58 0.74
stellar mass in solar units min-max 0.54 0.89
period in days min-max 6.411 6.416
duration in hours min-max 2.406 2.6au min-max 0.14 0.165
stellar diameter in solar units min-max 0.565 0.73
stellar mass in solar units min-max 0.47 0.77
period in days min-max 27.898 27.908
duration in hours min-max 4.002 4.399
Posted
-
by ajamyajax in response to zoo3hans's comment.
Re: 210744272: Hans Martin, is this another one of those bad cases you mentioned? Note changed period is similar to the others.
s1=2239.21 p1=11.412 d1=0.14 (3.36 hours)
(from an NEA proximity search)
K2 Targets within search area
EPIC Number RA [decimal degrees] Dec [decimal degrees] Distance [arc sec] Kepler-band [mag] Campaign Number
210744272 54.7602 19.0220 0.09 13.152 4
210744697 54.7494 19.0279 42.52 12.661 4
210742585 54.7672 18.9956 97.89 16.187 4
210743495 54.8003 19.0094 143.77 15.987 4
210747750 54.7666 19.0740 188.54 11.851 4Posted
-
by ajamyajax in response to ajamyajax's comment.
210836070: HM, this one could be contaminated by two P=11.41 transits (BGEB).
Posted
-
by ajamyajax
210568002: Martti from your list, possible blended BGEB here with half period transits visible at times through out this LC.
s1=2230.01 p1=1.522 d1=0.07 (1.68 hours)
EPIC, 2MASS, J mag, H mag, K mag, J - H, H - K, (J-H spectral type, stellar mass est) (H-K spectral type, stellar mass est)
210568002 , 2MASS J03581609+1629295 , 12.381 , 11.767 , 11.629 , 0.614 , 0.138 , ('K6V', 0.7) , ('K6V', 0.7)
au min-max 0.02 0.025
stellar diameter in solar units min-max 0.6 0.79
stellar mass in solar units min-max 0.46 0.9
period in days min-max 1.522 1.523
duration in hours min-max 1.625 1.712
Posted
-
by JKD
210823406 - mentioned as pot. EB on page 1 (some details below)
S at 2257.35 BKJD
transit duration ~6.37 hrs
dFlux ~165879 ppm
Posted
-
by ajamyajax
210957318: yes could be a nice hot gas giant candidate, using ~0.87X R_sol for the star here. The transits could be blended at times so the durations I get vary some, but all possible stellar radii are still within PC ranges.
s1=2230.802 p1=4.099 d1=0.10 (2.40 hours +/-)
EPIC, 2MASS, J mag, H mag, K mag, J - H, H - K, (J-H spectral type, stellar mass est) (H-K spectral type, stellar mass est)
210957318 , 2MASS J03292204+2217577 , 11.632 , 11.190 , 11.088 , 0.442 , 0.102 , ('K3V', 0.81) , ('K2V', 0.85)
au min-max 0.04 0.05
stellar diameter in solar units min-max 0.595 0.905
stellar mass in solar units min-max 0.51 0.995
period in days min-max 4.092 4.109
duration in hours min-max 2.154 2.649
Posted
-
by JKD
210825751 - pot. PC (already mentioned on page 1)
transit at ~2276.0 BKJD
transit duration ~0.20 d
dFlux ~8664 ppm
Posted
-
by JKD
210832801 - EB (see page 1) with an additional smooth
transit signature at 2299.45 BKJD
transit duration ~5.88 hrs
dFlux 1260 ppm
Posted
-
by JKD
210857749 - already mentioned on page 1, details see below
transit at ~2251.99 BKJD
transit duration ~14.71 hrs
dFlux ~179700 ppm
Posted
-
by ajamyajax
211089792: possible hot Jupiter candidate with a ~0.85X R_sol star. If the star is near Sun-size though, the estimated PC radius would be around 15.5X R_sol.
s1=2231.427 p1=3.2594 d1=0.10 (2.4 hours)
EPIC, 2MASS, J mag, H mag, K mag, J - H, H - K, (J-H spectral type, stellar mass est) (H-K spectral type, stellar mass est)
211089792 , 2MASS J04104086+2424061 , 10.622 , 10.168 , 10.062 , 0.454 , 0.106 , ('K2V', 0.85) , ('K2V', 0.85)
au min-max 0.035 0.045
stellar diameter in solar units min-max 0.695 0.97
stellar mass in solar units min-max 0.535 1.15
period in days min-max 3.251 3.27
duration in hours min-max 2.3 2.5
Posted
-
by ajamyajax
210769880: speculative planet candidate around a 0.62X R_sol star, but also could be a BGEB.
s1=2229.607 p1=1.43683 d1=0.065 (1.56 hours +/-)
EPIC, 2MASS, J mag, H mag, K mag, J - H, H - K, (J-H spectral type, stellar mass est) (H-K spectral type, stellar mass est)
210769880 , 2MASS J04100790+1924403 , 8.612 , 7.985 , 7.790 , 0.627 , 0.195 , ('K7V', 0.64) , ('K8V', 0.62)
au min-max 0.02 0.02
stellar diameter in solar units min-max 0.55 0.625
stellar mass in solar units min-max 0.515 0.52
period in days min-max 1.433 1.44
duration in hours min-max 1.402 1.593
Posted
-
by ajamyajax
210780851: although a fairly deep transit this is still a possible Jupiter PC, but note there is also a secondary transit (not pictured, see ephemeris).
s1=2232.377 p1=15.7808 d1=0.25 (6.0 hours +/-)
s2=2240.547 p2=15.7808 d2=0.25 (6.0 hours +/-)
EPIC, 2MASS, J mag, H mag, K mag, J - H, H - K, (J-H spectral type, stellar mass est) (H-K spectral type, stellar mass est)
210780851 , 2MASS J04031155+1934427 , 10.594 , 10.248 , 10.156 , 0.346 , 0.092 , ('G8V', 0.94) , ('K0V', 0.89)
au min-max 0.125 0.15
stellar diameter in solar units min-max 1.305 1.64
stellar mass in solar units min-max 1.045 1.81
period in days min-max 15.76 15.799
duration in hours min-max 5.852 6.149Edit: a newer fit with more corrected data:
Posted
-
by ajamyajax
210819089: possible eclipsing binary.
s1=2239.21 p1=34.22 d1=0.15 (3.6 hours)
s2=2256.91 p2=34.22 d2=0.15 (3.6 hours)
EPIC, 2MASS, J mag, H mag, K mag, J - H, H - K, (J-H spectral type, stellar mass est) (H-K spectral type, stellar mass est)
210819089 , 2MASS J03440216+2009354 , 11.517 , 11.009 , 10.885 , 0.508 , 0.124 , ('K3V', 0.81) , ('K3V', 0.81)
Posted
-
by ajamyajax
210609658: has one good transit in the MAST data, but at P=14.1x the duration might be too long to be planetary. Revisit with more corrected data.
Update: only two good transits in the corrected data, but the long duration still looks stellar as does the wide range of these stellar estimates.
s1=2241.395 p1=14.15 d1=0.51 (12.24 hours +/-)
EPIC, 2MASS, J mag, H mag, K mag, J - H, H - K, (J-H spectral type, stellar mass est) (H-K spectral type, stellar mass est)
210609658 , 2MASS J03425204+1706054 , 10.747 , 10.200 , 10.079 , 0.547 , 0.121 , K , ('K4V', 0.78) , ('K3V', 0.81)
au min-max 0.155 0.19
stellar diameter in solar units min-max 3.295 4.85
stellar mass in solar units min-max 2.48 4.575
period in days min-max 14.142 14.158
duration in hours min-max 10.7 13.705Posted
-
by zoo3hans in response to ajamyajax's comment.
EPIC 210389383 looks like a Hot Jupiter I think. Weak secondary transits are not unusual for big, hot Jupiters.
Full LC:
Zoom into LC:
Impact Parameter Calculator of Kian ( http://www.kianjin.com/bcalc.html ):
Posted
-
by ajamyajax in response to zoo3hans's comment.
Dear Hans Martin, I certainly hope you are right. You and Martti (but mostly you) found a good number of these too, so looking forward to seeing what happens with them. Nice work. Sincerely, Mark
Posted
-
by ajamyajax
211147528: if we can look past the "picket fence" fit here, could be another possible hot gas giant planet candidate if a Sun size star (+/-).
s1=2230.057 p1=2.3496 d1=0.10 (2.4 hours)
EPIC, 2MASS, J mag, H mag, K mag, J - H, H - K, (J-H spectral type, stellar mass est) (H-K spectral type, stellar mass est)
211147528 , 2MASS J03583532+2523189 , 10.884 , 10.710 , 10.619 , 0.174 , 0.091 , ('F6V', 1.25) , ('K0V', 0.89)
au min-max 0.03 0.035
stellar diameter in solar units min-max 0.645 1.045
stellar mass in solar units min-max 0.65 1.04
period in days min-max 2.345 2.357
duration in hours min-max 1.801 2.498
Posted
-
by ajamyajax
210744674: fairly deep transits at well over 2% and only one complete transit in the MAST data. Also the duration seems short for my stellar estimates here. So this one could be stellar, but check later with more corrected data (and to make sure not a glitch also). And sparse data so not pictured.
s1=2232.92 p1=25.22 d1=0.14 (3.36 hours)
EPIC, 2MASS, J mag, H mag, K mag, J - H, H - K, (J-H spectral type, stellar mass est) (H-K spectral type, stellar mass est)
210744674 , 2MASS J04232616+1901390 , 11.093 , 10.686 , 10.548 , 0.407 , 0.138 , ('K2V', 0.85) , ('K6V', 0.7)
au min-max 0.17 0.17
stellar diameter in solar units min-max 0.825 0.925
stellar mass in solar units min-max 1.03 1.03
period in days min-max 25.226 25.226
duration in hours min-max 4.357 4.885Posted
-
by ajamyajax
210775710: only two longer period partial transits here, but a possible planet candidate based on those partial shapes and transit depths, if not glitches. Check back with more corrected data.
s1=2231.672 p1=59.865 d1=0.26 (6.24 hours)
EPIC, 2MASS, J mag, H mag, K mag, J - H, H - K, (J-H spectral type, stellar mass est) (H-K spectral type, stellar mass est)
210775710 , 2MASS J03370580+1929585 , 10.631 , 10.307 , 10.208 , 0.324 , 0.099 , ('G5V', 0.98) , ('K3V', 0.81)
au min-max 0.24 0.315
stellar diameter in solar units min-max 0.68 0.945
stellar mass in solar units min-max 0.515 1.165
period in days min-max 59.826 59.867
duration in hours min-max 6.002 6.392Posted
-
by zoo3hans in response to ajamyajax's comment.
Another nice candidate from Martti, EPIC 210558622 :
Full LC:
Zooms into LC:
Assuming a K7 star (J-H=0.735, H-K=0.149, J=10.231, H=9.645, K=9.469, Kepler_mag=12.034, delta_mag=0.0015, period=19.564 days, estimated Teff=4500K) :
(using Kian's Planetary Kalculator)
Posted
-
by ajamyajax
210968143: a bit stellar or high impact or even blended, but a sub-Neptune planet candidate still seems possible here around small M-dwarf star (~0.55x R_sol).
s1=2231.905 p1=13.745 d1=0.12 (2.88 hours)
EPIC, 2MASS, J mag, H mag, K mag, J - H, H - K, (J-H spectral type, stellar mass est) (H-K spectral type, stellar mass est)
210968143 , 2MASS J03563656+2228216 , 11.168 , 10.495 , 10.360 , 0.673 , 0.135 , ('M7V', 0.098) , ('K6V', 0.7)
au min-max 0.09 0.095
stellar diameter in solar units min-max 0.52 0.61
stellar mass in solar units min-max 0.515 0.605
period in days min-max 13.742 13.75
duration in hours min-max 2.808 3.142Posted
-
by JKD
210945342 - agree with zoo3hans, this one looks like an EB.
However, there is an other interesting signal always ~0.14d before the signal starting at 2230.159 BKJD with about the same period like the EB (p~7.171d)Posted
-
by zoo3hans in response to JKD's comment.
Dear JKD
yes, the eclipse profile looks indeed very special. I assume it could be a large star spot, the eclipse duration is probably the whole feature, about 8.5 hours or so, since the secondary transit has also a rather long duration of about 8.5 hours (17 pixels). Maybe the orbits are locked and we see always the same side of the star during eclipse.
Zoom into eclipse:
Posted
-
by Shellface in response to zoo3hans's comment.
I would agree that the anomalous profile of the transits is due to spots, as the out-of-transit variability is clearly enormous and roughly equal in period to the orbital one, which is compatible with some form of tidally locked binary (though the modest transit depth suggests the companion may be fairly small). As the two periods are the same, a spot would "follow" the companion along its orbit and would be crossed every transit it is present, so the anomaly should be repetitive. Spots vary in form on a scale of a few rotational periods, so the shape of the anomaly should likely vary with time to some extent.
I would say that this is one of those peculiar objects for further study, because the scale of the phenomena it presents are extremely unusually large.
Posted
-
by JKD
Potential DN Candidates
ID 211079830 at 2274.608 BKJD
ID 211098921 at 2259.652 BKJD
Posted
-
by JKD
ID 211154046 - already mentioned on page 1 as EB
maybe there is a planetary compagnion
at 2247.332 BKJD with a
duration time of 2.94 hrs and a
minimal Flux of about 470 ppm
Posted
-
by ajamyajax
210525500: a tough one to fit, but perhaps a blended super-Earth planet candidate assuming a star ~0.9X R_sol. And at max depth, a PC here would still be only ~=2.4Re. Of course this transit could be contamination instead as Martti suggested earlier. Edit: there could be a secondary, but that would be blended also.
s1=2230.258 p1=1.369 d1=0.075 (1.8 hours)
EPIC, 2MASS, J mag, H mag, K mag, J - H, H - K, (J-H spectral type, stellar mass est) (H-K spectral type, stellar mass est)
210525500 , 2MASS J03354884+1549523 , 11.170 , 10.795 , 10.703 , 0.375 , 0.092 , ('G9V', 0.91) , ('K0V', 0.89)
au min-max 0.02 0.025
stellar diameter in solar units min-max 0.7 0.98
stellar mass in solar units min-max 0.565 1.125
period in days min-max 1.361 1.377
duration in hours min-max 1.705 1.899
Posted
-
Here are my corrected C4 results. Thanks to Al Schmitt (HEK) and Andrew Vanderburg (Harvard-Smithsonian Center for Astrophysics).
Note: Several targets may overlap candidates listed by myself or Hans Martin on page 1.
Apparent glitches:
2242.67 BKJD
ID (EPIC) | Period/Location
Planet Candidates:
210358034
210363145 (P = 8.199) TTVs present
210389383 (Possibly EB)
210402237 (P = 10.998)
210403955 Multi (at least 2 candidates)
210423938 (Possibly cont.)
210448987 (P = 6.102) Maybe cont.
210474116 (2253.11 BKJD) Maybe glitch
210500451 (2232.94 BKJD) Maybe glitch
210508766 Perhaps Multi system, though cont. might cause the events.
210509688 Could be glitches though
210534924 (2264.57 BKJD) Possibly glitch
EPIC 210558622 (P = 19.574)
210559259 Maybe
210566397
210577548 - Multi system (P1 = 6.421) (P2 = 27.838)
210578852 (2277.039 BKJD) Maybe
210598340 (P = 3.732)
210609658 (P = 14.136)
210629082 (P = 27.328)
210707130 (P = 0.6742)
210718708 (P = 8.774)
210731500 (P = 9.729)
210750726 Probably cont.
210754505 Probably cont.
210764361 (2277.07 BKJD)
210775710 (P = 59.835)
210780851 Probably EB cont.
210786627 Probably cont.
210793739 Probably cont.
210848071 (P = 41.691)
210853606 (2248.72 BKJD)
210903662 Probably cont.
210956385 (P = 56.627)
210957318 (P = 4.098)
210958990 (P = 1.702)
210961508 Probably cont.
210965800 (P = 8.746)
210968143 (P = 13.727)
EB Candidates:
210327060 Probably cont.
210341949
210343581
210350446 Maybe PC present
210355311
210356450
210361885
210362393
210367469
210370729
210373111
210373873
210375290
210375765
210376318
210378102
210386880
210389383 (maybe planet)
210391114
210401157
210403086
210404228
210411757
210413481
210414957 (Probably cont.)
210426551
210433146
210434247 (Probably cont.)
210437941
210451200
210453345
210454588
210467408
210470747
210471407
210471954
210472483
210474285
210475773
210476794
210483889
210484192
210489231
210493551
210501149 Maybe additional transit
210512162
210513446
210522228
210530173
210555161
210562330
210568214
210574135
210576234
210577546
210581202
210593417
210609071
210622523
210626797
210631263
210634139
210642322
210650657
210654881
210663545
210664740
210668314
210673168
210675130
210692406
210701530
210716489
210720575
210720772
210725198
210734262
210734337
210734643
210739713
210740200
210740526
210742688
210744182
210744674
210749423
210750052
210754643
210754756
210757799
210760314
210766835
210771656
210779706
210784039
210784223
210786847
210786891
210789323 Possibly additional transit at 2234.04 BKJD)
210793743
210796097
210803087
210805120
210810957
210817078
210821360
210822691
210823406
210824046
210827030
210832801
210835735
210837460
210840112
210843533 single dip
210846736
210857749
210863062
210865148 Triple EB
210876158
210879084
210908413
210912231
210925707
210935498
210941737
210945342
210954667
210954859
210960936
210961385
210965791
210969614
210989020
210989043
210991175
210991500
HB:
210433394
210801596
GDOR Candidates:
210348175
210354975
210390571
210396766
210427204
210437575
210438520
210460860
210462235
210491773
210498388
210516060
210516402
210517217
210529209
210568531
210672179
210692381
210697335
210711034
210716115
210725198
210737134
210746706
210752606
210758168
210759464
210769298
210769793
210772819
210796886
210806505
210810961
210819829
210849044
210859099
210862604
210895951
210912256
210948492
210967051
210977750
DSCT Candidates:
210344373
210747473
210765827
210857465
210979283
Cepheid candidates:
210855900
RR Lyrae Candidates:
210311535
210322126
210345648
210389601
210399040
210418729
210438688
210454384
210457607
210464181
210464781
210475866
210507908
210509604
210511418
210511770
210577318
210600482
210619926
210665016
210678680
210697426
210707203
210729707
210733035
210754711
210755194
210763406
210766289
210815465
210830646
210831816
210839363
210868876
210925792
210933539
CV/DN Candidates:
210662654
210670966
210865655
210886049
210890552
210911018
Mira Variables:
210332154
210401066
210418381
210420328
210421204
210421801
210439910
210447586
210472525
210479001
210479267
210496777
210520790
210532727
210666742
210675756
210686705
210788181
Other:
210359769
210427333
210447206
210488853
210818897
Asteroid Candidates:
210312511
210317331
210322477
210331148
210331848
210336461
210338942
210339090
210341601
210341825
210342315
210344843
210349237
210349838
210352052
210355269
210355626
210358866
210360999
210361325
210362756
210365226
210365286
210366107
210366175
210367033
210368793
210371702
210371851
210371890
210372865
210374294
210375568
210376151
210376318
210376917
210379141
210379999
210382177
210382657
210387639
210389478
210391196
210391582
210391779
210395925
210397353
210398038
210401037
210403086
210403748
210404228
210404888
210405044
210407071
210407396
210412108
210412589
210417498
210419253
210419493
210420164
210420306
210420401
210422158
210425323
210425716
210426073
210426606
210426688
210427629
210427758
210428037
210428344
210428551
210428765
210430458
210432080
210432517
210434525
210434938
210434976
210435394
210437356
210440088
210440093
210442792
210444246
210446822
210447014
210448213
210448947
210450012
210450449
210451321
210452146
210452501
210453085
210453830
210454404
210454684
210455646
210455921
210457290
210458488
210458576
210458873
210459047
210459098
210459199
210460262
210460381
210462150
210465351
210465375
210465397
210466150
210467231
210467408
210468157
210469324
210469721
210470484
210470525
210470747
210474992
210475773
210476385
210476426
210476837
210477101
210478124
210478228
210480098
210480719
210482495
210483775
210484276
210485181
210488694
210489127
210489239
210489346
210489853
210490365
210491103
210491271
210491311
210493265
210494413
210494644
210495014
210495260
210497173
210497875
210503288
210503575
210503612
210505000
210506107
210507407
210507827
210507908
210509455
210509992
210511033
210513615
210518239
210518739
210519453
210519528 <
210519749
210519982 *
210522494
210523892
210524041
210524395
210526473
210527747
210527925
210528811
210529424
210529971
210534263
210534732
210535170
210535186
210536061
210536937
210537905
210538133
210538598
210538996
210539287
210542983
210545912
210545941
210547105
210549532
210551045
210552677
210553304
210553775
210553950
210555933
210558216
210560927
210561994
210562819
210563003
210563410
210564081
210564347
210566008
210566910
210567516
210567628
210568200
210568214
210569604
210569770
210570358
210574135
210575024
210576234
210576774
210577268
210577632
210578381
210579563
210581202
210583507
210587542
210589260
210589582
210589916
210591703
210592463
210593490
210598655
210598969
210599217
210599981
210601109
210604966
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210608165
210609336
210610446
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210664901
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210667556
210670052
210670134
210672441
210674207
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210674692
210674696
210675130
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210681303
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210688360
210688461
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210691271
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210692324
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210694695
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210695955
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210699081
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210704133
210704834
210706205
210706309
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210707436
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210731765
210732574
210732952
210734337
210734852
210738971
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210742030
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210742592
210744092
210744764
210745240
210745695
210747190
210747217
210747390
210747688
210747698
210747818
210747837
210747932
210748025
210748060
210748446
210749423
210749850
210749928
210751234
210751641
210753975
210754523
210754849
210754930
210756714
210756734
210757163
210757756
210759564
210760422
210761053
210761169
210761838
210762740
210762863
210762875
210763921
210764183
210765795
210766338
210766884
210769047
210769333
210769813
210771355
210771662
210771734
210772588
210774635
210774656
210774807
210775959
210776021
210776124
210776486
210776647 Numerous
210776828
210778066
210780155
210780532
210780789
210780956
210780989
210781239
210781898
210781990
210783094
210783336
210784039
210786758
210786891
210787202
210788985
210789456
210789582
210790491
210791550
210792153
210792668
210793045
210793743
210795330
210796117
210796402
210798039
210799434
210799774
210799959
210800970
210802674
210804503
210804526
210808522
210810145
210811401
210811598
210813189
210813671
210814428
210816085
210816801
210819083
210819746
210819978
210820979
210821360
210822498
210822691
210822989
210826892
210828314
210829886
210829916
210830104
210830467
210831310
210831392
210832378
210832801
210833622
210834631
210835395
210837322
210838970
210839388
210840966
210841114
210841434
210843552
210843635
210846442
210846736
210847165
210848323
210849580
210853239
210853541
210854050
210854098
210854408
210855601
210855718
210856107
210856207
210857107
210860152
210862226
210862422
210863075
210863316
210865148
210865372
210865374
210865655
210866482
210868974
210869110
210869266
210870965
210871724
210872577
210872849
210872985
210873256
210874779
210875952
210876759
210878635
210879084
210879553
210879662
210880558
210880560
210881103
210883635
210885018
210885497
210885995
210886447
210886867
210888723
210890552
210891664
210892321
210892398
210893326
210893458
210894441
210894583
210894955
210896514
210896547
210898639
210898971
210901240
210901283
210904018
210904850
210905255
210905854
210906262
210906299
210907442
210907840
210907884
210908248
210909746
210910007
210910292
210910448
210911240
210911601
210915248
210915269
210915626
210915695
210916027
210917578
210918149
210919084
210919158
210920246
210920469
210921969
210922602
210922662
210922778
210923615
210924301
210925598
210926114
210926194
210926943
210927253
210927281
210927331
210928360
210929228
210930791
210931244
210933170
210934047
210934071
210934634
210934910
210935548
210936710
210936757
210936878
210937628
210939022
210939323
210939348
210940436
210940783
210941338
210941642
210942652
210942950
210943453
210943628
210944661
210944698
210945054
210945519
210945938
210946068
210946427
210946926
210947280
210947594
210947895
210948670
210948982
210949142
210949534
210949782
210950389
210951703
210952298
210953866
210953918
210954438
210955775
210956678
210956967
210957162
210958195
210959284
210959901
210963067
210963351
210963715
210963935
210964488
210964557
210965709
210965731
210966043
210966902
210966931
210967582
210967879
210967901
210968957
210969307
210970850
210971138
210972491
210972551
210973153
210974053
210974237
210974893
210976082
210977645
210978650
210978953
210979439
210979486
210981137
210981388
210982152
210982278
210982502
210982519
210982761
210983090
210983092
210983198
210986567
210986927
210987479
210988354
210988635
210989061
210989930
210991032
210991540
210991949
Posted
-
EPIC 210363145 (P = 8.199). Phase-folded signal (see Vanderburg lightcurve for TTVs):
EPIC 210402237 (P = 10.998). Phase-folded signal:
EPIC 210558622 (P = 19.574). Phase-folded signal:
EPIC 210577548 (P1 = 6.421). Phase-folded:
EPIC 210577548 (P2 = 27.838). Phase-folded:
EPIC 210598340 (P = 3.732). Phase-folded signal:
EPIC 210629082 (P = 27.328). Phase-folded signal:
EPIC 210731500 (P = 9.729). Phase-folded signal:
EPIC 210775710 (P = 59.835). Phase-folded signal:
EPIC 210848071 (P = 41.691). Phase-folded signal:
EPIC 210956385 (P = 56.627). Phase-folded signal:
EPIC 210957318 (P = 4.098). Phase-folded signal:
EPIC 210958990 (P = 1.702). Phase-folded signal:
EPIC 210965800 (P = 8.746). Phase-folded signal:
EPIC 210968143 (P = 13.727). Phase-folded signal:
Posted
-
by ajamyajax
Re 210363145: Martti, nice spotting on a smooth curve. Andrew's corrected data sure makes a difference. And agree this looks like another decent sub-Neptune planet candidate. The PC radius estimate shown is for a star ~0.85x R_sol.
s1=2237.81 p1=8.199 d1=0.133 (3.20 hours)
EPIC, 2MASS, J mag, H mag, K mag, J - H, H - K, (J-H spectral type, stellar mass est) (H-K spectral type, stellar mass est)
210363145 , 2MASS J03405481+1234216 , 10.384 , 9.910 , 9.799 , 0.474 , 0.111 , ('K2V', 0.85) , ('K4V', 0.78)
au min-max 0.065 0.08
stellar diameter in solar units min-max 0.67 0.885
stellar mass in solar units min-max 0.545 1.015
period in days min-max 8.199 8.21
duration in hours min-max 3.0 3.234Posted
-
by Martti_Holst_Kristiansen in response to ajamyajax's comment.
Thanks Mark, you are right they sure do. Also, good looking fit.
Posted
-
by zoo3hans
As usual I'm starting from the last one and I'm working toward Martti. (See also page 1 with results from the uncorrected data.)
Planet Candidates:
210968143 P=13.74 days. Nice candidate as Martti already pointed out in his list. So I stop here now. (also on page 1)
210978317 Maybe etremely long transit (17 days) from 2256 to 2273.
210991175 P=6.8578 days. Depth 0.005. Could be contamination by a BGEB, since small secondaries are visible.
210996142 Dip at 2267.25.
211002562 Period about 3.347 days. Nice Hot Jupiter. Depth 0.017. (also on page 1)
211043772 Dip at 2262.79.
211048999 P=5.17 days. Starting at 2233.6.
211064647 Maybe transit/eclipse at 2273.97, rather V-shaped.
211067990 Slight chance for a transit at 2293.93.
211087003 Probably a multi-planet system. Good large transit at 2251.1, smaller transit at 2231.15, 2259.45, 2287.75. P=28.3 days.
211089792 P=3.25875 days. It could be a typical Hot Jupiter. (also on page 1)
211106187 P=14.65 days. Starting at 2239.27
211108321 Dip at 2271.8.
211110086 Maybe long transit around 2240.
211133138 P=7.435 days. Starting at 2238.17. (also on page 1)
211147528 P=2.348 days, starting at 2232.4. (also on page 1)
211169300 P=16.45 days, first transit at 2234.8. (also on page 1)
EB Candidates:
210969614
210974364 P=32.75 days, depth about 0.07.
210975523 Dip at 2239.23. Depth 0.14.
211000135
211012889
211015722
211020446
211036449 Eccentrical EB
211038065 Eclipse at 2249.4.
211041532 Nice eccentrical detached EB.
211075893 Maybe eclipse at 2253.78.
211075914 Eclipse at 2266.22, maybe secondary eclipse at 2237.14.
211082420
211093684 Interesting triple system candidate, regular V-shaped eclipses (with small secondary eclipses in between), but additional long eclipse/transit around BKJD 2251 (depth about 0.023) ! Maybe another tatooine?
211096084 Maybe EB, depth is rather large (0.3).
211099781 P=7.56 days, small secondary transits/eclipses can be seen. Depth about 0.02, i.e it could also be a Hot Jupiter (profile is rather U-shaped).
211132787 Deep dips, must be an EB.
211135350 Maybe additional transit at 2252.2.
211147178 Nice detached EB
211154046 Nice detached EB with relatively long period
211155479 Eccentrical EB
211160700
211160717
211182027 Probably semi-detached giant EB
RR_Lyrae Candidates:
210994946
211048310
211069540
211069629
DSCT/GDOR Candidates:
210984540
210999011 D
211019860 D
211053882 D
211083721 D
211115338 D
211179336 D
Others:
210978953 Maybe asteroid crossing at 2290.46.
211045231 Maybe asteroid crossing at 2256.5.
211079830 Maybe asteroid crossing at 2274.6.
Posted
-
by ajamyajax in response to zoo3hans's comment.
Re 211169300: Dear Hans Martin all four transits seem to have different depths, so not sure what we can do with this one. (?)
More importantly, Hans Martin: Your two WASP-47 planets were confirmed recently however, so hope that cheers up your weekend!
http://exoplanetarchive.ipac.caltech.edu/docs/exonews_archive.html#08Oct2015
Posted
-
by ajamyajax
Re 210403955 from Martti's list: possibly three planet candidates here, including an uncommon small-ish super-Earth. Some transits there are partially blended so a star frequency or glitches or contamination as an explanation should be explored. But consistent stellar estimates I get anyway seem to support a planet. The star estimate used for these radii calcs is ~0.79X R_sol.
s1=2233.49 p1=5.603 d1=0.115 (2.76 hours)
s2=2244.616 p2=19.09 d2=0.16 (3.84 hours)
s3=2249.955 p3=28.842 d3=0.19 (4.56 hours)
EPIC, 2MASS, J mag, H mag, K mag, J - H, H - K, (J-H spectral type, stellar mass est) (H-K spectral type, stellar mass est)
210403955 , 2MASS J03560900+1333334 , 10.874 , 10.425 , 10.313 , 0.449 , 0.112 , ('K2V', 0.85) , ('K3V', 0.81)
au min-max 0.05 0.06
stellar diameter in solar units min-max 0.68 0.84
stellar mass in solar units min-max 0.53 0.92
period in days min-max 5.591 5.609
duration in hours min-max 2.706 2.795au min-max 0.125 0.14
stellar diameter in solar units min-max 0.69 0.81
stellar mass in solar units min-max 0.715 1.005
period in days min-max 19.081 19.097
duration in hours min-max 3.751 3.93au min-max 0.175 0.185
stellar diameter in solar units min-max 0.77 0.845
stellar mass in solar units min-max 0.86 1.015
period in days min-max 28.834 28.848
duration in hours min-max 4.506 4.691
Note two transit points between 2249.94 and 2249.97 BJD were corrected in this last fit for a possible glitch (or blending). See earlier transit close-up.
Posted
-
by Martti_Holst_Kristiansen in response to ajamyajax's comment.
Thanks Mark, another good looking fit! Btw, I originally flagged the C2 triple EB 😉, well too bad it was not published by PH.
Posted
-
by Dolorous_Edd in response to ajamyajax's comment.
EPIC 210403955
UKIRT image K-band
Posted
-
by ajamyajax in response to Martti Holst Kristiansen's comment.
Re: "I originally flagged the C2 triple EB"
Sorry Martti of course I should have looked all the way back and nice original find by you then. And as usual too. 😃
Posted
-
by zoo3hans in response to ajamyajax's comment.
Dear Mark
this is a bit troublesome (about EPIC 211169300). And yes, WASP-47 is a really interesting system.
Could you look into 211099781 ? I'm not sure if it's an EB or a warm Jupiter.Cheers, Hans Martin
Posted
-
by Martti_Holst_Kristiansen in response to ajamyajax's comment.
No worries Mark! And yes, not to forget, congratulations on WASP-47 c/d Hans Martin!
As for EPIC 211099781, I think it is an EB (secondary periodic eclipses).
Posted
-
by ajamyajax in response to zoo3hans's comment.
Yes and with corrected data, the picture becomes a little clearer. As Martti mentioned there is a significant secondary we need to consider. An albedo effect is a possible cause for this however, so hopefully there is still a chance for a HJ here. The transit depth is also a bit of a concern though as you well know. But I've thought one or two of these were EB's before and SF says no it could be an HJ, so will try to remain hopeful here anyway.
Note the duration was adjusted longer with this corrected data fit. And these transits were slighly malformed for whatever reason and were not included:
[ 2231.335 to 2231.615 BJD]
[ 2238.8993 to 2239.1793 BJD]
[ 2246.4636 to 2246.7436 BJD]
[ 2261.5922 to 2261.8722 BJD]
[ 2299.4137 to 2299.6937 BJD]Posted
-
by zoo3hans
EB candidate 211075893
zoom into LC with LcViewer: (corrected K2-C4 data)
I think the rise in the middle of the feature occurs because of an over-correction.
zoom into LC with Topcat: (raw K2-C4 data)
Posted
-
by Shellface in response to ajamyajax's comment.
But I've thought one or two of these were EB's before and SF says no it could be an HJ, so will try to remain hopeful here anyway.
That looks like an unblended EB (with a small stellar companion) to me. The eclipses are definitely too deep for a typical planet. Also, there appear to be ellipsoidal variations…
That's a very clean transit signal, though, so I'll probably be able to do analytical stuff. And the star is probably a Pleiad, so it could be important for stellar models.
Posted
-
by ajamyajax in response to Shellface's comment.
Appreciate that help, thanks.
Posted
-
by ajamyajax
Re 211087003 from Hans Martin's list: and a nice find of two gas giant planet candidates around maybe a Sun-size star, too.
As HM mentioned there is only one transit event visible for the second and larger transit, but I can guess its period at ~65 days (note a second event would be visible if that P ≤ 46.8). And this assuming ~0.95X R_sol and ~1.0X M_sol for the star. Also there could be a small albedo effect transit at the half-period interval as well, which might indicate a luminous planet if not a BGEB (heavens). The two observed could be coincidental dips in the flux however.
Also the P=28.x object might be a Neptune-class planet while the P=65.x object might be a Saturn-class planet at ~9.x Re.
s1=2231.17 p1=28.28 d1~=0.22 (5.26 hours)
s2=2251.112 p2=46.8+ d2=0.29 (6.96 hours)
EPIC, 2MASS, J mag, H mag, K mag, J - H, H - K, (J-H spectral type, stellar mass est) (H-K spectral type, stellar mass est)
211087003 , 2MASS J03571948+2421331 , 10.596 , 10.294 , 10.227 , 0.302 , 0.067 , ('G3V', 1.0) , ('G0V', 1.09)
au min-max 0.17 0.2
stellar diameter in solar units min-max 0.88 1.07
stellar mass in solar units min-max 0.82 1.335
period in days min-max 28.272 28.274
duration in hours min-max 5.209 5.386Semi-Major Axis a (A.U.) = 0.18165
Stellar diameter ratio = 0.95
Stellar mass ratio = 1.0
Period ~= 28.28 days
Duration ~= 5.26 hoursSemi-Major Axis a (A.U.) = 0.318
Stellar diameter ratio = 0.95
Stellar mass ratio = 1.0
Period ~= 65.5 days
Duration ~= 6.96 hoursUpdate: also noticed a slight dip in the flux at the half-period of P=63.8 (31.9 days), so if the larger object is luminous perhaps this is an albedo effect eclipse and ~63.8 days is the true period. Speculative, but the duration is similar to the transit's duration.
Semi-Major Axis a (A.U.) = 0.31249
Stellar diameter ratio = 0.95
Stellar mass ratio = 1.0
Period ~= 63.8 days
Duration ~= 6.9 hours
Posted
-
by zoo3hans
210961508 seems to have a period of 0.3499375 days. Depth about 0.001. Maybe a corora burner planet or contamination by a BGEB.
Posted
-
by ajamyajax
Re 210508766 from Martti list: another possible MPC find I think because multiple BGEB signals in one LC are pretty rare. And my alternating fits were inconclusive. So to me, these transits look like two short-period, mini-gas giant planet candidates around a small M-Dwarf. There is some blending which is not uncommon with shallow transit objects whatever they might be. And the stellar estimate used for these plots is ~0.64X R_sol.
s1=2231.3135 p1=2.7472 d1=0.08 (1.92 hours)
s2=2233.275 p2=9.998 d2=0.12 (2.88 hours)
EPIC, 2MASS, J mag, H mag, K mag, J - H, H - K, (J-H spectral type, stellar mass est) (H-K spectral type, stellar mass est)
210508766 , 2MASS J03593637+1533320 , 11.599 , 10.945 , 10.765 , 0.654 , 0.18 , M , ('M7V', 0.098) , ('K7V', 0.64)
au min-max 0.03 0.035
stellar diameter in solar units min-max 0.56 0.72
stellar mass in solar units min-max 0.475 0.76
period in days min-max 2.739 2.754
duration in hours min-max 1.82 2.015au min-max 0.075 0.085
stellar diameter in solar units min-max 0.59 0.71
stellar mass in solar units min-max 0.565 0.82
period in days min-max 9.981 9.996
duration in hours min-max 2.783 2.977
Note: technically, the 2253.3x BJD transit should have been removed because of transit overlap, but its effect should be minimal so I didn't this time.
Posted
-
by JKD
210416676 - maybe a PC at 2263.73 BKJD
Posted
-
by JKD
210421873 - 2 independent interesting signals at 2263.68 and 2266.84 BKJD
Posted
-
Unfortunately, I am quite confident that the events are glitches.
Posted
-
EPIC 211093684:
New paper out today: HII 2407: A Low-Mass Eclipsing Binary Revealed by K2 Observations of the Pleiades
Hans Martin, I thought that you initially mentioned something about a possible additional transit for this target, but somehow I can not find the post. Perhaps, I am wrong? Anyway, here is the event (Corrected Vanderburg lightcurve).
The feature is not present in C4 PDCSAP:
I used Troy's AKO-TPF tool and extracted the lightcurve. The primary and secondary EB signals can easily be seen but no signs of the aforementioned transit.
Posted
-
by ajamyajax in response to Martti Holst Kristiansen's comment.
Yeah, looks like that is the case for the event at 2263.69 BJD. Regarding the other possible transit (2266.835 BJD) I don't see other mentions. Have you seen this region on other light curves as a glitch? I ask because if so, I want to remove my spec analysis post so it isn't a distraction from other better candidates we have here. (Edit: previous analysis of 210421873 removed)
Posted
-
by zoo3hans in response to Martti Holst Kristiansen's comment.
Dear Martti
your memory serves you well, I wrote indeed on page 6 of this thread:
211093684 Interesting triple system candidate, regular V-shaped eclipses (with small secondary eclipses in between), but additional long eclipse/transit around BKJD 2251 (depth about 0.023) ! Maybe another tatooine?
Cheers, Hans Martin
Posted
-
by JKD
210357078
Transit signal at 2242.632 BKJD with
Duration time min. 6.374 hrs and
Flux min 579 ppm
Posted
-
by JKD
210357523 - possible transit next to a glitch area
Transit signal at 2250.131 BKJD
Duration time min 4.90 hrs
Flux min. 1235 ppm
Posted
-
by JKD
210358034 - PC already mentioned by Martii on page 6
No follow-up so far
Transit at 2263.626 BKJD
Duration Time 4.4.11 hrs (min)
Flux 1342 ppm (min)
Posted
-
by JKD
210364503 - Planet Candidate at
2242.612 BKJD
Transit duration 5.884 hrs
Flux 4669 ppm
Posted
-
by ajamyajax
210448987: looks ok to me as a blended planet candidate with fairly consistent M-dwarf estimates. A star radius of ~0.64x R_sol used here.
s1=2231.343 p1=6.1023 d1=0.10 (2.4 hours or so)
EPIC, 2MASS, J mag, H mag, K mag, J - H, H - K, (J-H spectral type, stellar mass est) (H-K spectral type, stellar mass est)
210448987 , 2MASS J03495652+1430080 , 12.048 , 11.419 , 11.316 , 0.629 , 0.103 , ('K7V', 0.64) , ('K2V', 0.85)
au min-max 0.055 0.06
stellar diameter in solar units min-max 0.595 0.675
stellar mass in solar units min-max 0.595 0.775
period in days min-max 6.098 6.108
duration in hours min-max 2.351 2.442Posted
-
by ajamyajax
211012889: really distinct alternating depth transits here, so this one must be a EB or BGEB.
s1=2246.34 p1=0.8698 d1=0.05 (1.2 hours or more)
EPIC, 2MASS, J mag, H mag, K mag, J - H, H - K, (J-H spectral type, stellar mass est) (H-K spectral type, stellar mass est)
211012889 , 2MASS J04145912+2310481 , 12.630 , 11.908 , 11.659 , 0.722 , 0.249 , ('M8V', 0.082) , ('M2V', 0.5)
Posted
-
by Martti_Holst_Kristiansen in response to ajamyajax's comment.
Yes, I have seen the 2266.855 BKJD event quite a few times. I just found an example in which both signals are present:
Posted
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by Martti_Holst_Kristiansen in response to zoo3hans's comment.
Oh, hmm.. do not know how I could miss that. Thank you Hans Martin!
Posted
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by ajamyajax in response to Martti Holst Kristiansen's comment.
Martti, thanks for posting an excellent example of those particular glitches. Since these one-time events can apparently be very transit-like in C4 (and perhaps earlier in K2), I'd better refrain from doing any more analysis on those. Sorry in advance for anybody hoping for a chart and a second opinion there.
Posted
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by JKD
210367322 - maybe a PC transit
MdPt Time 2261.08 BKJD
Duration Time 6.86 hrs
Signal Depth 2443 ppm
Posted
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by ajamyajax
210991175: alternating shallow transit depths so transit could be a BGEB as Hans Martin indicated.
s1=2231.785 p1=6.8565 d1=0.10 (2.4 hours)
s2=2235.21 p2=6.8565 d2=0.10 (2.4 hours)
EPIC, 2MASS, J mag, H mag, K mag, J - H, H - K, (J-H spectral type, stellar mass est) (H-K spectral type, stellar mass est)
210991175 , 2MASS J04102315+2250018 , 8.497 , 8.243 , 8.192 , 0.254 , 0.051 , ('F9V', 1.14) , ('F3V', 1.43)
Posted
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by JKD
210385888 - potential PC
Signal: 2247.25 BKJD
Transit Duration: 5.39 hrs
Signal Depth: 980 ppm
Posted
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by JKD
210386880 and 210386883 are obviously the same EB system (corrected)
Posted
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by JKD
210387006 - potential PC
Signal: 2245.42 BKJD
Transit Duration: 2.45 hrs
Signal depth: 1448 ppm
Posted
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by JKD
210387553 - potential PC
Signal: 2261.98 BKJD
Transit Duration: 3.92 hrs
Signal Depth: 1455 ppm
Posted
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by ajamyajax in response to JKD's comment.
Good to know, JKD. Thank you.
And I should have thought of this earlier, but just wrote a small program that looks for duplicate 2MASS entries in my color lists (just a quick list to scan for these). Here are the two JKD mentioned and a few other duplicates in the C4 data:
210386880 , 2MASS J03453431+1309330 , 9.465 , 8.950 , 8.866 , 0.515 , 0.084 , 'K3V'
210386883 , 2MASS J03453431+1309330 , 9.465 , 8.950 , 8.866 , 0.515 , 0.084 , 'K3V'210324184 , 2MASS J03594004+1128262 , 8.131 , 7.917 , 7.786 , 0.214 , 0.131 , 'F7V'
210324198 , 2MASS J03594004+1128262 , 8.131 , 7.917 , 7.786 , 0.214 , 0.131 , 'F7V'210406345 , 2MASS J03363025+1336459 , 6.078 , 5.317 , 5.070 , 0.761 , 0.247 , 'M9V'
210406347 , 2MASS J03363025+1336459 , 6.078 , 5.317 , 5.070 , 0.761 , 0.247 , 'M9V'210492943 , 2MASS J03575202+1517333 , 8.683 , 8.508 , 8.436 , 0.175 , 0.072 , 'F6V'
210492962 , 2MASS J03575202+1517333 , 8.683 , 8.508 , 8.436 , 0.175 , 0.072 , 'F6V'210701669 , 2MASS J03545714+1823126 , 10.810 , 10.485 , 10.373 , 0.325 , 0.112 , 'G8V'
210701688 , 2MASS J03545714+1823126 , 10.810 , 10.485 , 10.373 , 0.325 , 0.112 , 'G8V'210904552 , 2MASS J03545704+2127395 , 10.166 , 9.610 , 9.416 , 0.556 , 0.194 , 'K4V'
210904564 , 2MASS J03545704+2127395 , 10.166 , 9.610 , 9.416 , 0.556 , 0.194 , 'K4V'211023597 , 2MASS J04020461+2320455 , 9.363 , 9.306 , 9.251 , 0.057 , 0.055 , 'A7V'
211023618 , 2MASS J04020461+2320455 , 9.363 , 9.306 , 9.251 , 0.057 , 0.055 , 'A7V'Posted
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by davidbundy77
EPIC 210512842 - APH0000q6k
As spotted by Layman Sterms and Hildifons on "Talk" this star has possible transits every 5.87 days starting at BKJD 2234.1787.
The transit duration is about 0.20 days and the depths of the clearest transits are about 0.0006.
There is a fainter star visible on Aladin Lite at a distance of about 10´´.
Posted
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by ajamyajax in response to davidbundy77's comment.
210512842: sure looks like a planet candidate find by true Planet Hunters here. : )
Just my opinion of course, but the star appears to be smaller than our Sun. How much smaller is tough to pin down with the range in my quick estimates here. I went with a midrange value of ~0.75X R_sol in the chart, which yields a possible PC with a super-Earth radius around 1.34Re. There is always a chance this could be a BGEB, but didn't see much sign of that.
And this system is also on four planetary-titled proposals which gives it more credence as a planet candidate, but of course also means we aren't the first to think that. However I hope a possible discovery is still a thrill for those who saw this transit.
s1=2234.13 p1=5.8715 d1=0.11 (2.64 hours +/-)
EPIC, 2MASS, J mag, H mag, K mag, J - H, H - K, (J-H spectral type, stellar mass est) (H-K spectral type, stellar mass est)
210512842 , 2MASS J04012997+1537300 , 10.778 , 10.386 , 10.299 , 0.392 , 0.087 , ('K0V', 0.89) , ('G8V', 0.94)
au min-max 0.05 0.06
stellar diameter in solar units min-max 0.6 0.77
stellar mass in solar units min-max 0.485 0.835
period in days min-max 5.864 5.875
duration in hours min-max 2.504 2.695**PROPOSAL # PI TITLE GO4007 **
GO4007 Winn K2 Planet-Search Targets from the Draft TESS Catalog
GO4029 Charbonneau Characterizing Small Planets and Stellar Jitter with the Combination of K2 and HARPS-N
GO4033 Howard The Masses and Prevalence of Small Planets with K2
GO4060 Coughlin Discovery and Vetting of K2 ExoplanetsUpdate: 210512842 probably not a PC because a neighbor to 210512752 with a similar period transit. See my later post.
Posted
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by ajamyajax
Re 210598340 from Martti's list: a classic planetary transit fit, but what is it? Well, the duration seems too long for the near-Sun size star the colors here suggest. But that could mean maybe another subgiant or giant star, which would be neat. The target certainly looks reddish in the Aladin Lite image.
So let's look at the range of possibilities maybe: if the star were Sun-size, the transiting object could a HJ radius of ~12.3Re. At ~3.0X R_sol, the transiting object would be more like 36.9Re meaning another star at low impact (witnessing the flat transit).
Also I looked but didn't see any RAVE data for this one to help with the possible giant. The transit does seem connected to stellar flux cycle which could be more of a stellar indication, but didn't see any obvious sign of a secondary. So always hoping for a nice HJ but in previous transits like this, I think we favored them as more likely to be stellar.
s1=2233.825 p1=3.7345 d1=0.2375 (5.7 hours)
EPIC, 2MASS, J mag, H mag, K mag, J - H, H - K, (J-H spectral type, stellar mass est) (H-K spectral type, stellar mass est)
210598340 , 2MASS J03472850+1656298 , 11.222 , 10.953 , 10.876 , 0.269 , 0.077 , ('G2V', 1.0) , ('G6V', 0.97)
au min-max 0.06 0.075
stellar diameter in solar units min-max 2.53 3.28
stellar mass in solar units min-max 2.065 4.065
period in days min-max 3.721 3.739
duration in hours min-max 5.6 5.799
And note this transit event removed from the fit because of apparent glitches:
2241.17525 to 2241.41275 BJD
Posted
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by ajamyajax in response to ajamyajax's comment.
Update: aw shucks, I just remembered about the NEA search option that shows nearby stars, including EPIC numbers if there are any found. Turns out EPIC 210512842 is 8.03 arcsecs away from 210512752... And 210512842 is a brighter 12.106 Kep Mag star, while 210512752 is the dimmer 16.773 Kep Mag. And both light curves show the transit spotted separately on PH, with a very similar period of course. So, I was probably wrong about BOTH of these being possible planet candidates because it's unlikely a planet transit would contaminate another light curve. So my guess is the same background binary is causing these separate light curve transits because both are so shallow and blended. Sorry about that.
Aladin Lite image of 210512842:
Posted
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by davidbundy77 in response to ajamyajax's comment.
The two light curves are virtually identical. It looks like the signal from the brighter star has completely swamped the dimmer star. I am not giving up all hope yet.
Posted
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by ajamyajax in response to davidbundy77's comment.
Fair enough. That seems like the best case for a planet candidate there, so hope you are right.
Posted
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by ajamyajax
Re 210956385 from Hans Martin's and Martti's lists: only two events but they do appear similar, so this could be a sub-Saturn planet candidate if a smaller M-dwarf. ~0.72X R_sol used for these stellar estimates. Note there is a very bright ~6 Kep Mag star several arc-minutes away as seen in the Aladin Lite image. VSX identifier information also listed below. 2MASS is J03495506+2214390.
s1=2232.417 p1=56.627 d1=0.225 (5.4 hours +/-)
EPIC, 2MASS, J mag, H mag, K mag, J - H, H - K, (J-H spectral type, stellar mass est) (H-K spectral type, stellar mass est)
210956385 , 2MASS J03495538+2217036 , 12.625 , 12.230 , 12.103 , 0.395 , 0.127 , ('K0V', 0.89) , ('K4V', 0.78)
au min-max 0.235 0.275
stellar diameter in solar units min-max 0.595 0.74
stellar mass in solar units min-max 0.54 0.865
period in days min-max 56.621 56.634
duration in hours min-max 5.103 5.459Name, AUID, Coords (J2000), Const., Var. type, Period (d), Mag. range
NSV 15801, 000-BBG-296 03, 49 55.00 +22 14 39.0, Tau, ACV, 3.2509, 5.74 (0.01) U
http://www.aavso.org/vsx/index.php?view=detail.top&oid=54236Posted
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by ajamyajax
210786627: looks like this one is contaminated by possible EB 210786891 (also pictured) which is only 28 arcsecs away per an NEA radius search.
The ephemeris here was measured for 210786627 which matches both transits.
s1=2232.325 p1=1.7178 d1=0.11 (2.64 hours)
EPIC, 2MASS, J mag, H mag, K mag, J - H, H - K, (J-H spectral type, stellar mass est) (H-K spectral type, stellar mass est)
210786627 , 2MASS J03262216+1939563 , 11.011 , 10.447 , 10.325 , 0.564 , 0.122 , ('K6V', 0.7) , ('K3V', 0.81)
Posted
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by zoo3hans in response to ajamyajax's comment.
Thanks Mark.
See also https://www.cfa.harvard.edu/~avanderb/k2c4/ep210956385.html
Posted
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by JKD
210388236 - PC - Planetary Candidate
Transit at 2268.478 BKJD
Transit Duration 8.82 hrs
Signal Depth 2525 ppm
Posted
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by JKD
210389383 - looks like a regular EB
Posted
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by ajamyajax
210903662 from Martti's list: ok well, doing what I can here and inspired by a V-shaped HJ transit confirmed in a recent paper (see below), and by limb darkening comments from our friend Meg in the past (see her PH blog), I am going to guess this could be a grazing HJ also. This short-period candidate basically looks mostly planetary except for the stellar shape of the fit, and that could be from a high impact transit plus limb darkening on the star. Edit: the transit could be related to the flux cycle which could favor this one being more stellar.
There are some nearby stellar neighbors, but I check all four EPIC ID's that appear in a NEA search and none of them looked like a contaminating transit source. Of course another star in view still could be, but with a "quick" look you only get so much analysis you know. 😃 The possible PC radius estimate was measured for an also possible ~0.90X R_sol star.
s1=2232.84 p1=2.4103 d1=0.09 (2.16 hours)
EPIC, 2MASS, J mag, H mag, K mag, J - H, H - K, (J-H spectral type, stellar mass est) (H-K spectral type, stellar mass est)
210903662 , 2MASS J04001225+2126512 , 10.923 , 10.660 , 10.574 , 0.263 , 0.086 , ('G0V', 1.09) , ('G8V', 0.94)
au min-max 0.03 0.035
stellar diameter in solar units min-max 0.725 0.92
stellar mass in solar units min-max 0.62 0.99
period in days min-max 2.401 2.416
duration in hours min-max 2.064 2.259...
"EPIC 204129699b, a grazing transiting hot Jupiter on an 1.26-day orbit around a bright solar like star"
S. Grziwa, D. Gandolfi, Sz. Csizmadia, M. Fridlund, H. Parviainen, H. J. Deeg, J. Cabrera, A. A. Djupvik, S. Albrecht, E. B. Palle, M. Pätzold, V. J. S. Béjar, J. P. Arranz, P. Eigmüller, A. Erikson, J. P. U. Fynbo, E.W. Guenther, A. P. Hatzes, A. Kiilerich, J. Korth, T. Kuutma, P.Montanés-Rodríguez, D. Nespral, G. Nowak, H. Rauer, J. Saario, D. Sebastian, D. Slumstrup
http://arxiv.org/abs/1510.09149
and from NEA -- K2 Targets within search area:
EPIC Number RA [decimal degrees] Dec [decimal degrees] Distance [arc sec] Kepler-band [mag] Campaign Number
210903662 60.0511 21.4475 0.15 12.050 4
210903817 60.0464 21.4498 17.69 11.444 4
210904949 60.0561 21.4672 72.74 15.569 4
210905255 60.0400 21.4719 95.24 16.219 4Posted
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by Shellface in response to Shellface's comment.
EPID 211099781: I don't really want to take the hours to explain all the details for a system which, as it turns out, isn't very "useful", so I'll cover things briefly:
- Despite lying close to the Pleiades nucleus, the star does not align well with the Pleiades colour-magnitude diagram (which I took from this paper), so it is not a Pleiad. I later identified it as a background late-F - early-G subgiant, more likely on the earlier side do to the lack of rotational activity.
- The lightcurve of the system shows a very clear phase curve with significant ellipsoidal and Doppler beaming components. I observe semi-amplitudes of Aellip = 317.7 ± 8.3 ppm and Abeam = 185.1 ± 8.3 ppm, where the errors are as given.
- EXOFAST is able to model the transit lightcurve well, though it cannot account for the non-negligible effects of the companion mass on the transits. I can (roughly) account for them manually, however.
- After crudely modelling for additional effects, I get rough mass and radius estimates of M ≈ 1.3 Msol, R ≈ 2.5 Rsol and m ≈ r ≈ 0.3 times solar, assuming that the ellipsoidal variations are correct.
- However, the beaming amplitude disagrees with the above and indicates that q is lower; as Doppler beaming is largely relativistic, it is less likely to be incorrect than ellipsoidal variations. Doubly however, though, I cannot combine the beaming mass function with the transit-derived density and radius ratio to make realistic stellar parameters; I can only see this being resolved if there is a significant third light parameter, in which case the validity of the phase variation amplitudes is forfeit without information on the third light parameter.
With a clean transit lightcurve and clear phase variations, plus a fairly bright star (V = 12.4), this is a favourable target for studies of low-mass companions in EBs, though there are apparent difficulties in solving the system parameters, which may or may not be resolvable with RV observations. However, as an undoubtable EB, it is not an interesting target for Planet Hunters, and as it is probably not a Pleiad, it is not as astrophysically interesting as I had hoped.
Posted
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by zoo3hans in response to ajamyajax's comment.
EPIC 210609658 :
Well, the LC looks very much planetary to me. Bear in mind that C4 has the Pleiades and other young stars in its field. So maybe the star is actually a very low mass star (say 0.1 M_sol) with still a large radius. For example I could get a soultion like:
Posted
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by ajamyajax in response to zoo3hans's comment.
Well, I have several questions about this: is a 0.1 Msun/1.28 Rsun ratio even possible outside of a red giant? I mean I can get the same theoretical results as you in my calculations, but for example would a pre-main sequence star like this even be visible? The field is definitely DSS-colored red in Aladin Lite including this star.
Also about the possible planet, how would a gas giant get so close "so fast" if this is a young star? I thought migration in from colder regions was the prevailing theory on how hot Jupiters come to be. But what you propose is definitely a stimulating idea and I hope you are right because it could be an important observation. I need to do more research though in both areas and hopefully find other examples to support your argument. (Edit: what I am saying is, I just don't know yet.)
Posted
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by zoo3hans in response to ajamyajax's comment.
Well, this is all wild speculation on my part, but it seems that young stars are bigger and cooler than normal stars, see for example http://arxiv.org/abs/1505.02446 . If a raduis of more than 1 R_sol is plausible I have no idea.
Another possibility could be an opaque accretion disk around the star with a radius of 1-3 R_sol, although I would expect more variablity in the LC in such a case (as in a T-Tauri star).Posted
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by Shellface
A mass of 0.1 Msol is extremely fanciful. Pre-main-sequence masses at a given spectral type are generally similar to that of a main-sequence star of the same spectral type, so I disagree strongly with a 0.1 Msol mid-K PMS star.
The star lies in the bottom-right of Taurus, which is not a region with a known PMS population to my knowledge.
I can roughly estimate the stellar density to be ~5% of solar from the transit length, which is more compatible with a K-subgiant than a pre-main-sequence K star. For a mass of 1.3 Msol, R ≈ 3.0 Rsol. That would give r ≈ 0.2 Rsol, which is most likely stellar.
I'll probably run this through EXOFAST later, but this looks like a very-low-mass stellar companion to me.
Posted
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by Shellface in response to ajamyajax's comment.
EPID 210957318: This target was pointed out early on as a Hot Jupiter candidate. Though the transits appear to be on the narrow side, the lightcurve looks reasonably good to the eye.
The star has some good quality photometry, even though it is relatively faint (V = 13.5, Kep = 13.2). These give a spectral type of ~K3, with an error of less than 1 subtype. Its significant proper motions of [25.9, -13.6] ± [2.3, 2.4] mas/yr indicate that the star is a dwarf, as an evolved star of such late spectral type and low brightness would have to lie very distant, and would struggle to reach such proper motions.
There are two notable nearby stars that are brighter than the target, EPID 210956759 and EPID 210956858. However, they both lie ~30" away from EPID 210957318, which makes it unlikely that either contributes a significant amount of flux; indeed, both other stars have data availability, and both show no traces of the transits. Additionally, none of the stars have compatible proper motions to high significance, so none of them are gravitationally bound. Searching the 2MASS PSC reveals no other stars within 10", so blending is largely excluded, and can only be due to a star within a couple of arcseconds of the target.
The out-of-transit lightcurve is mainly composed of a slow trend, which is likely to be at least partially systematic. The lack of identifiable rotational variability suggests the host star is old, as it implies either low-amplitude or long-period variability. This is particularly valid as K-dwarfs are typically strong rotational variables, with semi-amplitudes of something like 1%.
I detrended the photometry as usual, and fed it to EXOFAST with a prior on Teff of 4900 ± 150 K and an unconstraining Fe/H prior. Without particular constraint to the density-related parameters, this was the resulting model:
The good matches between the fitted stellar parameters and the stellar spectral type are clear without additional priors, supporting the association of the transits to the target (note that the Fe/H is not physically constrained, and models with Fe/H >0.2 result in only slight parameter changes). The clean transit shape is also visible. The short transits lead to a necessary high impact parameter, though the good resolution of ingress/egress means that b is well constrained to ~0.65, hence this does not strongly influence the modelled stellar parameters.
Though the companion appears to be small for a Hot Jupiter - which are almost characteristically inflated above their expected radii - this is likely impacted upon by its relatively low equilibrium temperature. Indeed, for Hot Jupiters with Teq ≈ 1000 K, a radius of ~1.0 Rjup is in fact fairly average. This can be construed as support for the planetary interpretation of the companion, though I would caution against taking this very strongly.
Overall, this is a convincing clump Hot Jupiter around a fairly cool star. With an expected RV semi-amplitude of >30 m/s, follow-up is very possible despite the relatively faint host. Though perhaps fairly mediocre compared to known planets, this is still one of K2's few new Hot Jupiter candidates, and is a favourable target for further observation. Planet candidate / probable planet.
Posted
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by ajamyajax in response to Shellface's comment.
SF: regarding 210609658, is an inflated hot Jupiter puffed up by an older subgiant possible here? Just noticed this recent Kelt survey paper where a HJ of 1.699 R_jup and 0.902 M_jup was reported discovered. I wondered if this period/distance might be a bit too great for such inflation, but took a look at NEA confirmed planets and (edit: corrected) Kepler-435 has a P=8.6x and is 1.99 R_jup and its star is said to be 1.538 M_sol and 3.21 R_sol. Just a thought, is all.
"KELT-4Ab: An inflated Hot Jupiter transiting the bright (V~10) component of a hierarchical triple"
http://arxiv.org/abs/1510.00015
Posted
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by Shellface in response to ajamyajax's comment.
I'd say the possibility is worth considering, but ~2 Rjup is at the extreme upper tail of the planetary radius distribution, hence why I said "most likely stellar". Though, after all, K-subgiants are pretty luminous, and subgiant evolution is fairly quick, so there's some possibilities. Still, let us merit caution.
Like I said, I'll look at this analytically later. Probably next.
The Pleiades seems to have been drier than I had hoped, unfortunately. Perhaps all the rotational activity masks shallow signals?
Posted
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by jiipee
EPIC210960330, 2mass id: 04032022+2220488
Quite obvious transit at approx. d 21.25-21.9 (Q1-2)
linkDSS seems ok, not likely contaminated. However, this is a variable star, which is rather interesting, if confirmed planet
Posted
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by ajamyajax in response to Shellface's comment.
And this one could be near 2 Rjup, based on my quick fit of two transits anyway... This using your estimate of 3.1 R_sol. Another approximation of course, but my theoretical orbit calc below that works around these numbers as well. So looking forward to your closer look, whenever you have the time of course (no hurry).
Semi-Major Axis a (A.U.) = 0.1278
Stellar diameter ratio = 3.105
Stellar mass ratio = 1.39
Period ~= 14.15 days
Duration ~= 12.24 hoursPosted
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by ajamyajax in response to jiipee's comment.
Re 210960330 from Jiipee and other Planet Hunters: just an opinion of course, but this one is tricky because the possible transits could be anything.
There are two events that are close in duration however, but the stellar estimates I get make those difficult to suggest as maybe planetary. So my best guess is maybe an eccentric EB, assuming the second repeat of this possible secondary is landing on a glitch area. Sorry I couldn't do any better for you here.s1=2239.10 p1=32.38 d1=0.45 (10.8 hours)
s2=2246.72 p2=32.38 d2=0.38 (9.12 hours)
EPIC, 2MASS, J mag, H mag, K mag, J - H, H - K, (J-H spectral type, stellar mass est) (H-K spectral type, stellar mass est)
210960330 , 2MASS J04032022+2220488 , 6.570 , 5.701 , 5.450 , 0.869 , 0.251 , ('L1V', '...') , ('M2V', 0.5)
au min-max 0.24 0.275
stellar diameter in solar units min-max 2.23 2.6
stellar mass in solar units min-max 1.76 2.645
period in days min-max 32.371 32.387
duration in hours min-max 10.705 10.899Posted
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by zoo3hans in response to ajamyajax's comment.
EPIC 210960330 : s1 seems plausible, s2 does definitely NOT work, especially around 2279.
Zooms into LC:
and
Posted
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by Shellface in response to ajamyajax's comment.
This star is definitely an M-giant, as it's far too bright to be a dwarf at its spectral type. The vigorous rotational activity indicates this is an unblended EB of some sort, though without a good radius estimate it's difficult to say how large the companion is.
Posted
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by ajamyajax
*** Update: 210483889 looks contaminated by eccentric EB 210484192 -- see later post and charts ***
Re 210483889: this PH pick has a V-shaped transit and looks stellar. The fit depth would be about 15.6Re using a 0.93x R_sol star estimate.
http://talk.planethunters.org/#/subjects/APH0000pqd
s1=2236.075 p1=7.196 d1=0.14 (3.36 hours)
EPIC, 2MASS, J mag, H mag, K mag, J - H, H - K, (J-H spectral type, stellar mass est) (H-K spectral type, stellar mass est)
210483889 , 2MASS J03540357+1508137 , 11.630 , 11.013 , 10.886 , 0.617 , 0.127 , ('K6V', 0.7) , ('K4V', 0.78)
au min-max 0.07 0.08
stellar diameter in solar units min-max 0.895 1.08
stellar mass in solar units min-max 0.885 1.32
period in days min-max 7.186 7.202
duration in hours min-max 3.264 3.456Posted
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by ajamyajax in response to ajamyajax's comment.
Update: 210483889 looks contaminated by eccentric EB 210484192, only 16.65 arc seconds away:
from NEA, K2 Targets within search area:
EPIC Number RA [decimal degrees] Dec [decimal degrees] Distance [arc sec] Kepler-band [mag] Campaign Number
210483889 58.5149 15.1372 0.20 13.519 4
210484192 58.5140 15.1417 16.65 8.894 4 (P=7.19632)
210482444 58.5169 15.1110 94.41 18.017 4
Posted
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by Ptd
http://talk.planethunters.org/#/boards/BPH0000005/discussions/DPH0001amu
EPIC 210961508
Toasty little number here, nice spot by several people, it maybe has friends.
Posted
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by ajamyajax
Just a note here that 210678858 a possible C4 MPC:
Posted
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by Dolorous_Edd
EPIC 210908968
Possible PC
http://talk.planethunters.org/#/boards/BPH0000005/discussions/DPH000199y
Posted
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by ajamyajax
Re 210958990 from Martti's list: fairly deep transit so probably a binary, but a chance for a hot Jupiter if a 1.0x R_sol star. There could be a secondary however.
s1=2232.79 p1=1.702 d1=0.095 (2.28 hours)
EPIC, 2MASS, J mag, H mag, K mag, J - H, H - K, (J-H spectral type, stellar mass est) (H-K spectral type, stellar mass est)
210958990 , 2MASS J04110096+2219311 , 11.143 , 10.843 , 10.709 , 0.3 , 0.134 , ('G3V', 1.0) , ('K6V', 0.7)
au min-max 0.025 0.03
stellar diameter in solar units min-max 0.9 1.18
stellar mass in solar units min-max 0.715 1.255
period in days min-max 1.694 1.711
duration in hours min-max 2.18 2.376From NEA, K2 Targets within search area:
EPIC Number RA [decimal degrees] Dec [decimal degrees] Distance [arc sec] Kepler-band [mag] Campaign Number
210958990 62.7540 22.3253 0.16 12.613 4
210958453 62.7373 22.3165 64.12 12.672 4Posted
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by ajamyajax
Re 210965800 from Martti's list: identified as HAT 259-0002667 on VSX (see below). Seems like the transit could be a possible sub-Neptune candidate if not a star spot etc. 0.80x R_sol estimate.
s1=2237.34 p1=8.747 d1=0.13 (3.12 hours)
EPIC, 2MASS, J mag, H mag, K mag, J - H, H - K, (J-H spectral type, stellar mass est) (H-K spectral type, stellar mass est)
210965800 , 2MASS J03313333+2226055 , 10.786 , 10.426 , 10.292 , 0.36 , 0.134 , ('G8V', 0.94) , ('K6V', 0.7)
au min-max 0.075 0.085
stellar diameter in solar units min-max 0.73 0.875
stellar mass in solar units min-max 0.735 1.07
period in days min-max 8.75 8.751
duration in hours min-max 3.031 3.218From NEA, K2 Targets within search area:
EPIC Number RA [decimal degrees] Dec [decimal degrees] Distance [arc sec] Kepler-band [mag] Campaign Number
210965800 52.8889 22.4349 0.12 12.134 4
210965666 52.8502 22.4326 128.98 15.825 4Per VSX:
Dist. ' Name AUID Coords (J2000) Const. Var. type Period (d) Mag. range
0.00 Variable HAT 259-0002667 -- 03 31 33.33 +22 26 05.6 Tau ROT 8.68712507 10.79 J (0.022r)ROT: "Spotted stars that weren't classified into a particular class. All the SPOTTED stars in the UNSW list and the very small amplitude spotted stars found by Kepler are included here. Also, some stars that don't fit the current subtypes due to their physical properties have been classified as such (brown dwarfs and white dwarfs with spots). It may be used as a subtype when a T Tauri star shows rotational variability (TTS/ROT, CTTS/ROT or WTTS/ROT)."
Posted
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by Dolorous_Edd
Posted skyview images for number of candidates
List WIP (not complete! will be updated )
EPIC 210775710 - http://talk.planethunters.org/#/boards/BPH0000005/discussions/DPH0001b1b
EPIC 210960330 - http://talk.planethunters.org/#/boards/BPH0000005/discussions/DPH0001apr
EPIC 210403955 - http://talk.planethunters.org/#/boards/BPH0000005/discussions/DPH0001apq
EPIC 210968143 - http://talk.planethunters.org/#/boards/BPH0000005/discussions/DPH0001ap5
EPIC 210402237 - http://talk.planethunters.org/#/boards/BPH0000005/discussions/DPH0001am7
EPIC 210956385 - http://talk.planethunters.org/#/boards/BPH0000005/discussions/DPH0001amq
EPIC 210903662 - http://talk.planethunters.org/#/boards/BPH0000005/discussions/DPH0001amv
EPIC 210448987 - http://talk.planethunters.org/#/boards/BPH0000005/discussions/DPH0001aor
EPIC 210957318 - http://talk.planethunters.org/#/boards/BPH0000005/discussions/DPH0001aoi
EPIC 211147528 - http://talk.planethunters.org/#/boards/BPH0000005/discussions/DPH0001akl
EPIC 210605073 - http://talk.planethunters.org/#/boards/BPH0000005/discussions/DPH0001ao7
EPIC 210961508 - http://talk.planethunters.org/#/boards/BPH0000005/discussions/DPH0001amu
EPIC 210750726 - http://talk.planethunters.org/#/boards/BPH0000005/discussions/DPH000113d
Posted
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by zoo3hans in response to Dolorous_Edd's comment.
Thanks DE
appreciated, as always.
Posted
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by Dolorous_Edd in response to zoo3hans's comment.
Thanks, hope at least some of them will be helpful
Posted
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by Dolorous_Edd
EPIC 211002562
There is a small star visible to the NW
UKIDSS K-band 1'x1'
Posted
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by Dolorous_Edd
EPIC 211099781
A companion can be seen in both the UKIDSS and CFHT image less than 2" away
CFHT I2-band
Posted
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by Dolorous_Edd
EPIC 210389383
UKIDSS K-band 1'x1'
Clearly seen companion to the SW
Posted
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by Dolorous_Edd
EPIC 210558622
UKIDSS K-band
1'x1'
Posted
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by Dolorous_Edd
EPIC 210568002
UKIDSS k-band
1'x1'
Posted
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by Dolorous_Edd
EPIC 210957318
In addition to UKIDSS - http://talk.planethunters.org/#/boards/BPH0000005/discussions/DPH0001aoi
Was imaged by Subaru telescope W-S-R+
Same with different color scaling
Posted
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by Dolorous_Edd
EPIC 211089792
UKIDSS K-band
1'x1'
Clearly seen close companion
Posted
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by Dolorous_Edd
EPIC 210780851
UKIDSS K-band
1'x1'
Close companion can be seen to the NE
Posted
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by Dolorous_Edd
EPIC 210819089
UKIDSS 1'x1'
K-band
If binary , at least not visual
Posted
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by ajamyajax
210389383 revisited: looks more like an EB by transit depth with Huber/NEA value of 1.46 R_sol.. And as was previously mentioned there is a secondary present also. It has an eccentric transit which indicates a binary as well.
s1=2236.77 p1=14.089 d1=0.254 (6.10 hours +/-)
EPIC, 2MASS, J mag, H mag, K mag, J - H, H - K, (J-H spectral type, stellar mass est) (H-K spectral type, stellar mass est)
210389383 , 2MASS J04102487+1313037 , 11.257 , 10.905 , 10.772 , 0.352 , 0.133 , ('G8V', 0.94) , ('K6V', 0.7)
Semi-Major Axis a (A.U.) = 0.12
Stellar diameter ratio = 1.46
Stellar mass ratio = 1.16
Period ~= 14.08 days
Duration ~= 6.1021 hoursFrom NEA, K2 Targets within search area:
EPIC Number RA [decimal degrees] Dec [decimal degrees] Distance [arc sec] Kepler-band [mag] Campaign Number
210389383 62.6037 13.2177 0.10 12.752 4
210390632 62.6122 13.2463 107.17 10.519 4, HD 286545 -- Star on Simbad, Proper motions mas/yr: 28.5 -1.1, Spectral type: F5epic_number,tm_name,ra,dec,k2_teff,k2_rad,k2_mass,k2_kepmag,k2_pmra,k2_pmdec,k2_dist
210389383,2MASS J04102487+1313037,62.603675,13.217711,6111.00,1.46,1.16,12.752,13.800,2.200,458.90
210390632,2MASS J04102693+1314465,62.612210,13.246251,6187.00,1.70,1.26,10.519,28.500,-1.100,228.50Posted
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by ajamyajax
Also note the different depths of the primary transits in the more corrected data... This just to demonstrate that while those algorithms provide wonderful clarity to the K2 data, they do at times affect transits. Minimally corrected data can sometimes provide a more neutral view, especially of deeper binary transits as shown in my MC data fit of the previous example (210389383).
Posted
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by Artman40
http://arxiv.org/abs/1606.05812
EPIC 210363145. It's a mini-neptune orbiting a K-star and is located near Pleiades. Lack of planet detections in Pleiades itself and subsequent transit insertion simulations indicate that it's not easy to detect planets in Pleiades.
Posted
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by Shellface in response to ajamyajax's comment.
EPID 210780851: At a glance this appears to be a giant planet candidate, but as others have observed the lightcurve exhibits shallow eclipses, so the companion cannot be planetary. Still, the companion must be small and the lightcurve has excellent signal-to-noise, so it is worth inspecting the system more closely to see what can be said.
There seems to be an unusual disagreement between the colours of the target. To compare the indices and their implied spectral types:
B-V = 0.529 ± 0.072: F8 ± 3
J-H = 0.346 ± 0.043: G8 ± 4
V-K = 2.299 ± 0.049: ~K2.5 ± 0.5
It seems that either the Johnson indices are too bright, or the 2MASS indices are too faint. Edd has pointed that there is a companion at ~1-2", but it looks too faint to explain the above discrepancies.
The Huber et al. Teff is 6149 ± 148 K, with a reddening of E(B-V) = 0.19. Though reddening is non-negligible in the area this value seems to be too large, and the Teff would be inconsistent with the unreddened B-V. Thus, I assume a preliminary value of Teff = 5700 ± 400 K that is intermediate of those implied by the spectral types, and indicate that this is susceptible to revision.
There are no stars within 20" in the EPIC or the 2MASS PSC. Though Edd has pointed out a companion too close to be detected by either, with limited information it is not possible to discuss its nature. As it appears to be faint I choose to assume it has negligible effect on the primary, though this may not be entirely valid.
The lightcurve is dominated by a systematic trend, as per usual. Below this there is some low-frequency variability which may be rotational. Though it is difficult to to determine the period because the amplitude is low (~200 ppm), it appears to be close to the orbital period at 15.78 days. This may be indicative of tidal interaction between the components.
I detrended the lightcurve for transits and eclipses in the usual manner. The EXOFAST fit to the transits, assuming zero eccentricity and with Teff = 5700 ± 400 K as a prior, is shown below:
The impact parameter is well-constrained, owing to the good resolution of ingress. Thus the fitted a/R is likely precise, which means that the low host density is probably real, even without modelling a non-zero companion mass and assuming e = 0. The host star is probably leaving the main sequence, though its radius is not currently that large.
The companion radius is likely within a few decimal places of 1.8 Rjup, for a modest error on R. This is too large to be planetary at its moderate insolation, so a stellar companion is preferred even without considering the eclipse.
The photometric rms is 80 ppm, which is quite low for the system brightness (Kep = 12.2, V = 12.5). This appears to be compatible with photon noise, indicating that there is little high-frequency variability.
The eclipse profile, phased to the transit time and period, is shown below:
There is some excess variability in the eclipse depth, which is likely due to the processing algorithm being unable to detect the eclipses a priori and subsequently over-aggressively detrending them. It is thus difficult to evaluate the true depth of the eclipse, so I assume a conservative value of 300 ± 100 ppm.
EXOFAST gives the eclipse time as (BJD-2454833) 2240.5447 ± 0.0014 and the eclipse duration as 0.236 ± 0.007 d. As can be seen in the above figure there is a small-but-significant offset between the eclipse and phase 0.50, indicative of a non-zero eccentricity.
Following (T(2)-T(1))/P = Φ, the phase of the eclipse is Φ = 0.51729 ± 0.00009. Then, by using the following equation:
e cosω = π · (Φ-0.5)/(1+cosec²(i)), where ω is the argument of periastron for the companion
Assuming i = 88.7 ± 0.3° (itself assuming b = 0.45 ± 0.10 and a/R = 20.3 ± 0.5), e cosω = 0.02717 ± 0.00014. Though omega cannot be directly constrained by this value, under a random distribution for ω there is an 82% probability that e < 0.1, so it can already be assumed that the orbital eccentricity is low.
e sinω can be constrained by the following:
e sinω ≈ (1-x)/(1+x), where x = D(2)/D(1), the ratio of eclipse duration to transit duration
For x = 0.927 ± 0.029, e sinω ≈ 0.038 ± 0.016. Since we now have two equations for e and ω, it is possible to solve for both values; the results are e ≈ 0.047 ± 0.013 and ω ≈ 54.4 ± 12.3°, with e α ω (i.e e is highest when ω is largest, and vice-versa).
From this, most of the parameters of the orbit have been solved from the photometry alone. Only the semi-major axis remains unknown due to the unknown system mass, though it is still determinable in a relative sense. This shows the power that eclipses have on the determination of system parameters, where they are detectable.
When an eclipse is total, and assuming the two components are the only significant sources of flux in the lightcurve, the luminosity ratio of the components follow the equation:
L(2)/L(1) = δ(2)/(1-δ(2)), where δ(2) is the eclipse depth.
Note that as δ(2) -> 0, 1-δ(2) -> 1 so δ(2) -> L(2)/L(1). For an eclipse depth of 300 ± 100 ppm, L(2)/L(1) = 0.0003 ± 0.0001.
Consider the modified Stefan-Boltzmann Law, L = 4πR²σT⁴. In the case of a ratio between two stars:
L(2)/L(1) = (R(2)/R(1))²(T(2)/T(1))⁴
L(2)/L(1) = (R/r)²(T(2)/T(1))⁴
(r/R)² is equal to transit depth for low impact parameter, and as demonstrated above L(2)/L(1) is an eclipse derivable. Thus, for small L(2) and low impact parameter:
δ(2)/δ(1) ≈ (T(2)/T(1))⁴, i.e the ratio of eclipse depth to transit depth is equal to the temperature ratio of the components to the fourth power.
Since L(2) is small and b is low, the approximation is valid here. For δ(2)/δ(1) = 0.0003 ± 0.0001, T(2)/T(1) = 0.363 ± 0.031; for Teff(1) = 5700 ± 400 K, Teff(2) = 2069 ± 322 K. I suspect this is an underestimate - it lies within the BD range, but r seems to be too large for that to be true - though nevertheless it does clearly indicate that the companion lies towards the bottom of the main sequence.
To conclude, this is a binary consisting of a late-F - early-G primary with a very late-type secondary with a slightly eccentric orbit. This system is a good example of how much can be derived from an EB lightcurve even when the companion approaches planetary size, and hopefully shows what will be routinely possible when photometry reaches a level when the detection of planetary eclipses becomes commonplace.
I chose this system in particular because it is quite bright, at V = 12.5. Those who may be interested in characterising a very-low-mass star with reasonably long period would find this a useful target, as determination of its mass should be possible with only a few RVs.
Posted
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by Shellface in response to zoo3hans's comment.
EPID 210945342: This is a unique system. Even though it is difficult to model analytically, I will attempt to infer its nature.
The most obvious feature of the lightcurve is the enormous rotational signal. With a semi-amplitude of ~12% it is far larger than the rotational variability seen on any normal star. Next come the transits and eclipses; at ~3% and ~1% they are shallow for an EB. They also phase consistently with the rotational signal; the equality between the orbital and rotational periods show that the primary is tidally locked to the secondary, which usually only occurs when the masses are similar. Third is the most unusual part, the extremely odd transit profile. All of the transits show a large "spike" just before the mid-transit, which can very clearly be seen when the transits are phase-folded:
The orange line marks what might be expected of a "normal" transit (please excuse the slight offset from phase 0.5). The variability around the peak is real and acts transit-to-transit, indicative of some temporal variability in the phenomenon. On the other hand, the phase of the brightening is very consistent, so the brightening occurs at the same time relative to every transit.
The most logical cause for this phenomenon, as zoo3hans indicated, is a large spot. When a transiting object crosses a starspot, a magnetically complex cool area on the stellar surface, the amount of light blocked by the companion decreases as spots emit less light than the rest of the surface, so there will be a positive bump in the transit. Spot crossings have been observed during transits of stars and planets alike, but I am not aware of anything as large as this.
Spot crossings are compatible with the observed rotational signal, as well. The large amplitude of the variability indicates the spot(s) moving across the star are proportionally large, compatible with the large bump in the transit profile; the transits always occur just prior to the minimum of the rotational period, so the spots should be slightly offset from the centre of the stellar disk, and indeed the brightening always occurs slightly before the mid-transit time. One can imagine a system architecture something like the mockup shown below:
I am not aware of any expression that relates rotational amplitude to spot size, so the depicted size is a guess. The companion radius, however, should be reasonably accurately scaled even when considering the somewhat indeterminate transit depth (δ between 0.04 and 0.05 gives r/R between 0.2 and 0.22, and I chose δ = 0.045).
What can be said of the types of the components? The colours of the object give a (reddened) spectral type of ~K7, and the long transits indicate the primary is a giant. The Huber et al. parameters seem to peg the star as a bright giant (class II), but the transit length implies a density more like a regular giant (class III). Regardless of the exact nature of the primary, evolved stars are habitually magnetically quiet, so the large rotational amplitude is undoubtedly due to the companion.
Using the expression for temperature ratio used in the above comment, T(2)/T(1) in this system appears to be ~0.70 ± 0.04, most of the uncertainty stemming from the poorly determined true radius ratio. For Teff(A) of, say, 4500 ± 200 K, Teff(B) = 3150 ± 350 K, which is ~mid-M in spectral type; the companion is probably an M-dwarf.
Though it is difficult to parameterise a giant with what little information is available, with a transit density of ~0.1 g/cm^3 the companion radius r comes out as ~0.5 Rsol even for a low primary mass of 1.0 Msol. This is at about the highest value allowed by the temperature range for an M-dwarf, so the results are roughly consistent. M = 1.0 Msol would imply a system age of ~11 Gyr; though this seems unlikely, the Huber et al. metallicity is very low, which tentatively suggests the star is around this old. A more proper determination of the system parameters would depend on follow-up observations.
It would probably take some dedicated modelling to get good parameters from the lightcurve, because I have never seen such an extreme case of starspot crossings. Still, despite the difficulty, this is a very unusual system that deserves some proper attention.
Posted