C5 - C16 overlap targets

by Shellface

Today it was announced that Campaign 16 will be changed into a forward-facing campaign. This is to replace the planned C17, due to concerns over the remaining spacecraft fuel. Though principally designed for the observation of supernovae in other galaxies, other science programs are explicitly supported, and I imagine observation of galaxies will not require as much pixel space as C9 (the other forward-facing campaign) did.

Anyway, something highly relevant to us is noted in the announcement:

The new pointing for Campaign 16 will have significant overlap with the field observed during Campaign 5. The final field position will be posted to this website in the near future.

Depending on the exact position of the C16 field, there may be several detectors worth of overlap with C5. Undoubtedly this would contain several planet candidates, and it seems probable that their reobservation would be highly justified. The details are not yet decided, but it seems reasonable to make a thread already.

Due to the change in field location, the proposal deadlines for Cycle 5 (C14-16) have been extended by a bit over a month.

Posted September 12, 2016 9:51 PM
by Shellface

There is currently a preliminary position for C16 on the K2 website, which is RA = 8:50, dec = 17:00. The position of the C5 field is 8:40, 16:50, so if the final C16 position is anywhere near the preliminary one it will overlap almost entirely with C5.

This is rather significant. C5 covered many extremely interesting targets, such as the Praesepe planet hosts and the extraordinary HIP 41378, and there are hundreds of objects suitable for re-observation. If extragalactic observations do not require a near-total proportion of the available pixels, it should be possible to get away with observing a large number of targets.

If the overlap ends up being large, it would be more efficient to list the stars that won't be re-observed than the stars that will.

On the website it is stated that the C16 position will be finalised by the 20th, so we shall see what the overlap is on tuesday.

Posted September 18, 2016 8:41 PM
by ajamyajax

Just released K2fov v.6.0 produced a C5/C16 count of 7488.

https://www.dropbox.com/s/g3312yp22twr7e9/c5_c16.zip?dl=0

(newer)

K2fov v.7.1.1 produced a C5/C16 count of 6997 (stellar targets only)

https://www.dropbox.com/s/md7raqzkkmum3pr/c5_c16.zip?dl=0

Posted September 22, 2016 2:36 PM
by Shellface

The final positioning is not as favourable for re-observing as I had hoped. Still, the overlap rate is 29%, which is not a small fraction.

The C16 field position is given as 8:55, 18:31, noticeably more northerly than C5. This means that the southernmost targets of C5 are unfortunately not re-observable, including HIP 41378. Praesepe is positioned awkwardly, with the nucleus partially falling off the detector, so some important targets are missed. M67 is about half off-silicon, but as none of the cluster members have (yet) had transiting planets identified this is not obviously problematic.

From some brief inspection, some interesting targets in the overlap are:
- K2-34 (EPIC 212110888), a reasonably bright hot jupiter host
- The overlapping Praesepe hosts, EPIC 211822797, 211901114, 211913977, 211969807, and 211970147
- EPIC 212006344, which appears to be a fairly bright M-dwarf with a ~terrestrial planet
- bright stars EPIC 211945201 and EPIC 211682544, for which mass measurements are plausible
- EPIC 211924657, which shows TTVs
This is far from exhaustive, and it will take some effort to produce a streamlined target list. In addition, it is quite likely there are some targets of unrecognised significance in the overlap.

Posted September 22, 2016 11:45 PM
by Shellface

The pointing change has received an official announcement. This includes a handy diagram of the C5 and C16 fields (note that detector 4 is not marked in the C5 silhouette, though it was functional at the time).

To get the ball rolling:

K2-34 (EPIC 212110888) has been confirmed independently by three different groups (Lillo-Box et al., Hirano et al., Brahm et al.), using a total of 6 different spectrographs (HARPS-N, SOPHIE, CAFE, HDS, CORALIE, FEROS). To my knowledge, only a handful of planets have been confirmed three times (in the sense of independent discovery; many have been studied by other groups following publishment), and none with so many spectrographs. I would guess that this is because most hot jupiter hosts this bright observed by K2 were previously identified from the ground, so in this case there was the additional incentive of confirming a new planet.

There is WASP photometry for this target, accessible via the NASA exoplanet archive. The reason the transits were not detected is because they do not actually appear, because the 2.996-day orbital period is so close to 3 days that they never occurred during night for that WASP photometer. The 0.1%-accurate comeasure in time found here is a very unlikely circumstance, and had it not been the case the planet would probably have been confirmed before C5.

With three papers on the subject, the system parameters are rather tightly constrained. One new element is that the star has a Gaia DR1 parallax, but at 3.28 ± 0.68 (stat.) ± 0.3 (sys.) mas it is not precise enough to constrain the stellar luminosity better than it already has been. The three sets of published parameters generally agree within their errors.

All three studies find high impact parameters for the planet, at about b = 0.85. As of such the transits are fairly short considering the evolved host star. Even if the the transit features are fairly well-resolved, the model fit stands to benefit considerably from short cadence observations.

Posted September 25, 2016 9:31 PM
by ajamyajax

Re 211409178 from the c5/c16 targets overlap list: in the speculative but looking for transits anyway category, maybe several blended super-Earth or somewhat larger planet candidates around a Sun-size star. One seems to fit, but could of course still be anything.

s1=2300.6 p1=6.715 d1=0.10 (2.4 hours +/-)

s2=2310.3 p2=14.72 d2=0.1375 (3.3 hours +/-)

s3=2307.99 p3=9.782 d3=0.08 (1.92 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)

211409178 , 2MASS J08553005+1146512 , 11.444 , 11.071 , 11.006 , 0.373 , 0.065 , ('G9V', 0.91) , ('F9V',1.14)

Semi-Major Axis a (A.U.) = 0.117

Stellar diameter ratio = 1.0

Stellar mass ratio = 0.98

Period ~= 14.728 days

Duration ~= 3.3013 hours

Estimated duration for center of star transit ~= 4.488 hours

From NEA, K2 Targets within search area:

EPIC Number RA [decimal degrees] Dec [decimal degrees] Distance [arc sec] Kepler-band [mag] Campaign Number

211409178 133.8752 11.7809 0.0 12.608 5

211406658 133.8658 11.7427 141.75 14.301 5

epic_number,tm_name,ra,dec,k2_teff,k2_rad,k2_mass,k2_kepmag,k2_pmra,k2_pmdec,k2_dist

211409178,2MASS J08553005+1146512,133.875249,11.780919,5693.00,1.00,0.98,12.608,-10.500,-12.300, 352.7±293.3

Posted September 27, 2016 8:10 PM
by Shellface

EPIC 211945201: This is a fairly typical system, but the brightness of the star makes this an important target for further study.

At V = 10.15, this star lies within the brightest 5% of K2 planet host candidates. As it appears in the Tycho catalogue it has a Gaia DR1 parallax, 6.04 ± 0.63 ± 0.3 mas (167 ± 27 pc). This, combined with the V-band magnitude, an estimated spectral type of F8.5 ± 1.5 (6100 ± 150 K) and a thin-disk Fe/H of 0.0 ± 0.3 results in M = 1.09 ± 0.11 Msol, R = 1.21 ± 0.15 Rsol, and log g = 4.28 ± 0.10 cgs. The nominal values indicate a slightly evolved star, but the errors reach the main sequence.

No additional objects are found within 20" in 2MASS, the EPIC, or the Gaia archive, which reach faint enough magnitudes to exclude any blending beyond a few arcseconds. For smaller separations, AO observations are listed in K2FOP which show null detections. The star is very likely single, and there are no apparent sources for blends; this is important knowledge, considering the grazing transit profile.

Though proper analysis is hampered by the presence of the usual instrumental variability, there does not appear to be any significant rotational variability in the out-of-transit lightcurve. As EPIC 211945201 is fairly early-type this is not entirely unusual - the evolution of stellar magnetism changes significantly around the Kraft break, and spots become increasingly negligible for hotter stars - but it does suggest that the star is not a very rapid rotator, and is probably inactive. This is important for radial velocity observations.

I detrended the transit lightcurve in the usual manner. The resulting lightcurve was fed into EXOFAST with Teff = 6100 ± 150 K and log g = 4.28 ± 0.10 cgs as priors. This was the output:

A clear feature of the transit profile is the "picket fence" morphology, due to the orbital period being near-equal to a multiple of the long cadence integration timescale.of 29.4 minutes. In this case the two periods are equal within about 1 minute, or ~0.001% (1 part in 100,000). This means the transit features are poorly resolved, exacerbated by the apparent high impact parameter. The log g prior is necessary to maintain reasonable stellar parameters.

The EXOFAST transit depth appears to be accurate (for once!), so I leave it unchanged. For R = 1.21 ± 0.15 Rsol, r = 5.33 ± 0.66 Rearth. This lies in the sub-saturn desert, though it is at the bottom end and is not inconsistent with a large ice giant.

For a 5.3 Rearth planet, one would expect a mass of about 20 Mearth. This corresponds to a radial velocity semi-amplitude of ~4.5 m/s, which should be detectable with a few months of semi-dedicated observation assuming v sin i ~<15 km/s - which, due to the lack of activity in the lightcurve, is probably reasonable. I would not be surprised if this star has seen some observations already.

This is a bright target well-suited for follow-up, and it has a transit shape which would benefit greatly from short cadence, so SC for this star seems like a no-brainer. If a mass measurement is possible, I'm sure this is a planet which can get its own paper.

As an aside, I attempted a simple BLS periodogram search for additional planets. Nothing was particularly convincing, but there are some isolated transit-like shapes in the lightcurve. C16 observations would allow good constraints on other planets in the inner system.

Posted September 29, 2016 9:47 PM
by Shellface

EPIC 211924657: I have previously discussed this target in the C5 thread (page 19).

This is a mid-M dwarf transited by a ~2.0 Rearth companion every 2.65 days. While this would be a fairly interesting system on its own, it is made considerably more notable due to the presence of large TTVs. Here is the same transit time plot I showed before:

The TTV cycle is not closed in C5 observations, so it is not possible to properly study the signal with the available data. I previously stressed the importance of further transit observations, but it seems that issue has solved itself. This star would no doubt be an excellent target for re-observation.

While the C5 lightcurve shows that transit modelling in LC is feasible, despite the short transit duration meaning less than 5 datapoints occur per transit, SC observations would still be hugely beneficial. Short cadence would probably be of greatest benefit to measurement of the transit times and durations, which is otherwise difficult due to the poorly resolved transit features in LC.

Posted October 9, 2016 9:34 PM
by Dolorous_Edd

Well, I will do the same thing I did for previous overlap targets

I will cross-check with K2 C5 finds thread later

From EVEREST data

PC EPIC

212164470 - period 7.800

212154564 - period 6.413

212088059 - known planet, P=10.365 days

212069861 - Period 30.96 days; Mentioned by zoo3hans in C5 K2 thread

212011230 - single transit at BKJD 2332.48, depth 0.0053; Mentioned by zoo3hans in C5 K2 thread

212009427 - Known PC; period 1.557; looks like EB

211922654 - period ~18d or half of that (possible FP )

211919004 - Known PC ; period 11.718

211906259 - seems to be known pc ; period ~2d

211897691 - Known PC period 5.749; second set of dips? 2320.003 and 2339.5060, 2359.0, 2378.54?

211886472 - Known PC ; period = 19.632

211834065 - period 10.52 ; second set of dips? at 2314.53, 2325.07, 2337.14, 2346.18

211825799 - 2 transits ; period 33.335; depth 0.0006

211816003 - Known PC ; period 14.448

211814733 - Known PC? period 14.701; second set of dips period 14.701; EB?

211743874 - Known PC ; period = 12.278

211733267 - Known PC ; period = 8.657

211711685 - possible MPC!; maybe 3 planets ( first PC - period unknown at 2312.9, second PC = period 15.442 start at 2310.88, third PC = period 49.56 , start at 2323.75 ) (no ref)

211705654 - dips with ~2.52 period ; i.e. 2368.76

211695172 - period 0.625; depth 0.0015

211613886 - period 0.959 ; maybe EB contam; depth less than ~1%

211611158 - 2 transits ; period 52.704 ; start 2326.14 Mentioned by zoo3hans in C5 K2 thread

211606790 - 2 transits ; period 37.217 ; depth 0.007 Mentioned by zoo3hans in C5 K2 thread

211598816 - single dip at 2363.37; depth ~1% Mentioned by zoo3hans in C5 K2 thread

211586387 - Known PC ; period 35.393

211529065 - Known PC ; period 4.399; small dips at 2315.580, 2323.30, 2354.17, 2358.8, 2380.43?

211490999 - Known PC ; period 9.842 ; maybe also dip at 2311.3

211432103 - period ~0.93 Mentioned by Martti in C5 K2 thread

211413752 - Known PC ; 1 planet - period 9.328 ; another dip (second PC?) at 2315.488 , period 4.528?
(third PC? ) at 2335.46 period 26.266?

Good looking dips

212087300 at 2352.99

212082223 - good looking dip at 2325.315

212022415 - dip at 2321.03

211941577

211939409

211938359

211938121 Mentioned by zoo3hans in C5 K2 thread

211904757 - single dip at 2318.29

211897901 - single dip at 2348.61 Mentioned by zoo3hans in C5 K2 thread

211829796 - single dip at 2312.8

211818195 - single dip at 2349.19

211765775 - flares with multiple dips Mentioned by zoo3hans in C5 K2 thread

211754117 - more or less good looking dips; period 13.795 i.e at 2335.0216

211719798 - very good looking dip at 2307.37; U-shaped ; 7.356 ; ~0.0001 depth

211692065 at 2337.63 despite looking like glitch , it looks like it could be real dip

211633098 - glitchy LC, some dips look good i.e. 2323.31 ; 2372.799

211625873 - 2307.4 and 2352.4; long ~28h ; maybe glitch

211612060 - at 2309.6 ; glitch maybe

211517035 - at 2309.00 maybe also at 2350.21 , not sure if real

211436513 - at 2340.90 and 2354.93

211408522 - maybe dips at 2309.56 and 2373.26 - p = 63.697 ; depth 0.0003

211407755 - period ~36.08 days, at BKJD 2327.24 and 2363.32 Mentioned by zoo3hans in C5 K2 thread

EB's EPIC

212171851 - D - period 5.490 - ~40% depth - spots?

212165050 - interesting variable dips at 2330.138, 2346.94; 2363.81; 2380.56 don't fit LC

212164476 - C - period 0.284

212159519 - C - period 0.360

212116340 - C - period 0.610

212110007 - D - period 16.710

212109135 - D - period unknown - only 2 dips; at 2340.95 and 2365.12 ; depth ~35%; Mentioned by zoo3hans in C5 K2 thread

212098045 - C - period 0.872

212096658 - D - period 1.466 - depth ~20%

212085740 - D - period 4.846 - spots?

212083250 - maybe contamination by the EB

212082682 - D - period 3.797 - depth ~12% - spots?

212069706 - D - period 0.136 - shallow depth

212069380 - maybe EB? - period 0.268

212037403 - D - period 3.408 - spots?

212024647 - D - period 7.391 - bad correction? trinary? dips 2336.75, 2340.43, 2340.43

212020442 - D - period 7.780 - spots?

212019712 - C - period 0.953

212019055 - SD - period 0.820

212012387 - D - period 6.490 - 50% depth

212011476 - SD - period 1.432

212009702 - SD - period 0.462

212009131 - EB? period 0.243 ; flares

212008305 - period ~0.307

211999267 - possible HB - period 17.088

211972837 - SD - period 1.093

211942157 - SD - period 1.325 - dips at 2334.9 and 2337.58?

211927125 - SD - period 0.680

211920612 - SD - period 9.749 - 80% depth

211910237 - D - period 2.218

211900142 - C - period 0.186

211892898 - D - period unknown - single dips at 2356.392 and 2374.0 - Mentioned by zoo3hans in C5 K2 thread

211885185 - D - period 4.401

211839462 - EB contaminated

211839430 - EB contaminated

211836131 - C -period 0.700

211822953 - SD - period 1.550

211812724 - C - maybe period 0.607d

211812160 - SD - period 2.170

211806072 - C- period 0.421 - C

211805631 - D - period 0.531 - D

211770578 - D - period 40.404 - D

211770390 - D - period 7.577 - D

211744153 - D - period 4.611 - D

211732801 - D - period 2.133

211728918 - maybe EB?

211629697 - maybe HB ; interesting ; regular inverse transits - Mentioned by Martti in C5 K2 thread

211626833 - C - period 0.261

211619120 - D - period 11.098

211604396 - SD - period 0.437

211563123 - D - period 17.321 - almost %40 depth

211526186 - SD - period 0.455

211513489 - possible HB? - period ~26-27d - maybe with dips 2344.33 and 2360.92

211462458 - D - period 3.604 - maybe dip at 2374.26

211434817 - C - period 0.450

211432946 - D - period 3.343

211431013 - D - period 6.204

211430148 - D - period 15.089 - 40% depth

211416577 - SD- period 0.535 ;

211415469 - D - maybe dip at 2332.82

211412192 - period 0.441; C

211411112 - D - period uknown - dips at 2345.94 also maybe dip at 2313.13 - Mentioned by zoo3hans in C5 K2 thread

211408138 - D - period 10.329

211410762 - C

211409713 - D - period 3.1

211409299 - D - period 13.9

211405917 - C

211398788 - SD - period 0.558

RR lyr EPIC

228682502

228682498

212106005 - maybe contamination

212074806

212066778

211917094

211879654

211612680

211553019

211410664

Other EPIC

228682494 - Outburst at 2348.8 ; DN?

212162615 - flares; periodic variable

212160810 - flares; periodic variable

212156201 - flares; periodic variable

212117039 - flares; periodic variable

212111862 - flares; periodic variable

212110857 - flares; periodic variable

212088850 - flares; periodic variable

212081648 - flares; periodic variable

212075829 - GDOR / DSCT

212071674 - flares; periodic variable

212070650 - flares

212070382 - flares; periodic variable

212070332 - flares; periodic variable

212038642 - flares

212032504 - dip 2373.32 , looks glitchy

212028041 - flares; periodic variable

212027909 - flares

212027653 - flares

212021131 - powerful flare

212017730 - periodic variable

212013215 - GDOR / DSCT

212006447 - flares

212006411 - GDOR / DSCT

212006179 - flares

212006014 - flares

212001688 - flares

211999858 - flares

211903302 - flares

211901847 - flares

211899790 - flares

211898130 - flares

211897999 - flares

211897214 - flares

211896805 - flares

211896450 - flares

211894518 - pulsating

211893704 - flares

211892510 - flares

211891961 - flares

211891315 - Outburst at 2359.84

211890655 - LPV

211890433 - flares

211889174 - flares

211881232 - flares

211874609 - pulsating

211845034 - flares

211843541 - SSO cross at 2313.71

211841807 - flares

211836888 - flares

211834355 - flares

211832848 - periodic variable

211830319 - periodic variable

211829944 - flares

211829193 - flares

211823671 - flares

211822497 - flares

211821826 - flares

211819373 - periodic variable

211817361 - flares

211817077 - flares

211816343 - flares

211815922 - flares

211814364 - flares

211814310 - flares

211812650 - pulsating variable

211810213 - flares

211806798 - LPV?

211805237 - flares

211771406 - flares

211759143 - periodic variable

211745624 - pulsating

211745306 - flares

211743884 - flares

211743517 - LPV

211742207 - flares

211741792 - flares

211739012 - flares

211738528 - flares

211736524 - flares

211734069 - flares

211731949 - flares

211728289 - flares

211723172 - flares

211722117 - outburst at 2317.80 and flares

211719918 - periodic variable

211716610 - periodic variable

211716544 - flares

211715431 - flares

211709792 - flares

211708468 - LPV?

211707068 - flares

211703232 - flares

211702697 - flares

211701037 - flares

211697906 - flares

211695506 - flares

211694874 - GDOR

211694552 - DSCT?

211676580 - flares

211633247 - flares

211630360 - flares

211628214 - flares

211614522 - flares

211606939 - flares

211606444 - flares

211593145 - flares

211551682 - flares

211550616 - Interesting LC , deep dips 2326.90 and 2315.50

211548229 - GDOR

211546850 - flares

211528617 - flares

211521121 - flares

211504760 - strange raise at 2344.46, maybe glitch

211504156 - flares

211501996 - flares

211500697 - flares

211494780 - flares

211493551 - flares

211488310 - flares

211486736 - GDOR

211441334 - flares

211435416 - looks like SSO , but which one? at 2322.803

211434368 - flares

211430723 - flares

211427165 - periodic variable, period 2.821

211422201 - flares

211417750 - flares

211410200 - flares

211409376 - flares

211408887 - flares

211405240 - DSCT?

Doubtful dips EPIC

211936049

211918974 at 2348.935 and 2377.78

211911325 at 2342.15

211897895 at 2339.59

211845605 at 2318.7 and 2346.963

211842983 at 2322.27

211833760 at 2316.64

211816730 at 2319.88

211812508 - maybe ~1.527

211741469 at 2345.08

211737318 at 2357.914

211729782 at 2325.80

211725118 at 2319.49

211722736 at 2339.62

211721005 at 2373.28

211718187 at 2336.28

211706746 at 2364.187

211694281 maybe dip at 2370.112

211679711 at 2308.8 and 2380.10

211636252 at 2327.09

211627247 at 2364.024

211612680 at 2321.924 and 2332.81

211605895 at 2313.60 and 2365.86

211604802 at 2314.0 and 2319.52

211601880 at 2352.93 and 2313.445

211551176 at 2352.93

211530518 - at 2357.77

211526613 - 2 dips at 211526613 and 2337.67

211520001 at 2346.99

211515004 at 2325.94 and 2374.52

211513489 at 2360.92

211510277 at 2369.68

211507808 at 2341.8 and 2342.887

211507267 at 2342.99

211505372 at 2352.9

211503585 at 2337.667

211503567 at 2319.49

211490148 at 2368.91

211488307 at 2337.36

211486736 at 2314.13

211434311 at 2337.71

211432171 at 2307.69

211430941 at 2311.157 and 2365.475

211431172 at 2316.23, 2327.74, 2350.48,

211427210 at 2341.45

211417423 at 2345.26

211414351 at 2314.119

211411639 at 2338.668

211409604 at 2337.637

211406539 - 2307.540

211406658 - at 2343.93 and 2345.166

Posted October 10, 2016 11:41 AM
by zoo3hans in response to Dolorous_Edd's comment.

I mentioned EPIC 211407755 already as a PC with period 36.08 days at https://talk.planethunters.org/?_ga=1.89314651.1777704650.1398881647#/boards/BPH0000007/discussions/DPH00019on

I mentioned EPIC 211529065 already as a PC with period P1=4.4 days, starting at BKJD 2309.97, duration about 3 hours, depth 0.0013, at https://talk.planethunters.org/?_ga=1.89314651.1777704650.1398881647#/boards/BPH0000007/discussions/DPH00019on , it seems to have a smaller planet with P2=1.544 days (see later post with AKO images), starting at BKJD 2307.87, duration about 2.5 hours, depth 0.0007.

I mentioned EPIC 211765775 already as a PC with period P1=43.13 days at https://talk.planethunters.org/?_ga=1.89314651.1777704650.1398881647#/boards/BPH0000007/discussions/DPH00019on , in fact this seems to be an extremely busy system. Maybe Mark and Shellface should have a look into this. P2=27.93 days, starting at BKJD 2311.07, duration 11 days, depth 0.0004. P3=24.96 days, starting at BKJD 2315.65, duration 18.5 days, depth 0.0005. Maybe strong TTV's.

I mentioned EPIC 211919004 already as a PC with period 11.721 days at https://talk.planethunters.org/?_ga=1.89314651.1777704650.1398881647#/boards/BPH0000007/discussions/DPH00019on

New candidates:

EPIC 211404773 maybe single transit at BKJD 2341.94, duration 4 hours, depth 0.0015.

EPIC 211406658 single transit at BKJD 2343.98, duration about 9 hours, depth 0.001.

EPIC 211407435 P=18.73 days, starting at BKJD 2313.07, duration about 2 hours, depth 0.004.

211408138 EPIC 211408138 P=10.339 days, starting at BKJD 2316.71, duration about 8 hours, depth 0.017. Also on the large side, it might still be a PC or BD. Secondaries are very shallow (if at all). Mentioned by Ivan as an EB.

EPIC 211413752 Known PC, P1=9.328 days, starting at BKJD 2307.84, duration 4 hours, depth 0.001, P2=4.528 days (as Ivan found out), starting at BKJD 2309.20, duration 6 hours, depth 0.0008, P3=26.27 days, starting at BKJD 2307.84, duration 4.5 hours, depth 0.001.

EPIC 211427210 single transit at BKJD 2341.45, duration about 13.5 hours, depth 0.001.

EPIC 211432922 P=5.82 days, starting at BKJD 2308.9, duration about 4.5 days, depth 0.007.

EPIC 211514520 single transit at BKJD 2378.8, duration 37.5 hours, depth 0.0002.

EPIC 211529758 single transit at BKJD 2319.4, duration 44 hours, depth 0.0002.

EPIC 211604395 single transit at BKJD 2340.36, duration 6 hours, depth 0.0001.

EPIC 211616367 single transit at BKJD 2343.37, duration 24 hours, depth 0.02.

EPIC 211625363 single transit at BKJD 2319.5, duration 4 hours, depth 0.003. The other dips are not convincing.

EPIC 211631900 single transit at BKJD 2375.2, duration 33.5 hours, depth 0.0006.

EPIC 211633098 P=49.48 days, starting at BKJD 2323.3, duration 5.5 hours, depth 0.0006. Also a long single transit at BKJD 2344.5, duration 31 hours, depth 0.001.

EPIC 211688005 single dip at BKJD 2343.22, duration about 15 hours, depth 0.00025.

EPIC 211718462 dips at BKJD 2337.62, 2359.07, 2373.3.

EPIC 211754103 single transit at BKJD 2343.37, duration about 20.5 hours, depth 0.0001.

EPIC 211754117 P1=13.795 days, starting at BKJD 2307.44, duration about 3 hours, depth 0.0006, P2=39.79 days, starting at BKJD 2327.7, duration 3.5 hours, depth 0.0008.

EPIC 211764174 single dip at BKJD 2377.97, duration about 4 hours, depth 0.0006.

EPIC 211811294 P=30.24 days, starting at BKJD 2326.88, duration about 3 hours, depth 0.0001. Maybe some other dip at BKJD 2349.54.

EPIC 211813392 single transit at BKJD 2371.11, duration about 3 hours, depth 0.0004.

EPIC 211816730 single transit at BKJD 2319.89, duration about 2 days, depth 0.0003.

EPIC 211819363 single transit at BKJD 2375.0, duration about 1 day, depth 0.001.

EPIC 211820437 P=39.98 days, starting at BKJD 2328.04, duration about 6 hours, depth 0.0005.

EPIC 211822797 P=21.17 days, starting at BKJD 2311.41, duration 4.5 hours, depth 0.0014, mentioned by myself and Shellface.

EPIC 211825799 P=33.31 days, starting at BKJD 2328.1, duration 15 days, depth 0.0008.

EPIC 211830955 single dip at BKJD 2319.69, duration 4 hours, depth 0.0003.

EPIC 211711685 Multiplanet candidate, P1=unknown (I estimate it to be around 100 days, Rp=2.6 R_Earth), at BKJD 2312.98, duration 10.5 days, depth 0.0007, P2=15.45 days, starting at BKJD 2310.9, duration 5.5 hours, depth 0.0003, P3=49.92 days, starting at BKJD 2323.75, duration 8.5 days, depth 0.0003. Mentioned by Ivan.

EPIC 211842983 P=31.43 days, starting at BKJD 2322.3, duration about 29.5 hours, depth 0.0004. Maybe another (single) transit at BKJD 2317.33, duration about 20 days, depth 0.0003.

EPIC 211886849 P=32.16 days, starting at BKJD 2337.63, duration about 2.5 hours, 0.0008.

EPIC 211888215 signle dip at BKJD 2376.64, duration 3 hours, depth 0.015.

EPIC 211891698 single dip at BKJD 2326.83, duration 4 hours, depth 0.00015.

EPIC 211894311 single dip at BKJD 2340.40. duration 7 hours, depth 0.0003.

EPIC 211897691 known planet, P1=5.749 days, starting at BKJD 2309.49, duration 2 hours, depth 0.001, (new) P2=19.507 days, starting at BKJD 2320.0, duration 5 hours, depth 0.0013.

EPIC 211911990 P=28.42 days, starting at BKJD 2324.59, duration about 9 hours, depth 0.0005.

EPIC 211913984 single transit at BKJD 2354.98, duration 35.5 days, depth 0.0004.

EPIC 211922654 P=9.5 days, starting at BKJD 2306.63, duration 16.5 hours, depth 0.0007, mentioned by Ivan.

EPIC 211922849 P=9.46 days, starting at BKJD 2306.77, duration about 18 hours, depth 0.0001.

EPIC 211933524 single transit at BKJD 2341.32, duration 13.5 hours, depth 0.0001.

EPIC 211950081 good dips at BKJD 2334.36 and 2327.99, 2344.44 and others, duration about 2 hours, depth 0.0003.

EPIC 211973314 single transit at BKJD 2343.42, duration 20 hours, depth 0.0001

EPIC 212002276 single dip at BKJD 2349.21, duration 13.5 hours, depth 0.001.

EPIC 212006344 known planet, P=2.22 days, starting at BKJD 2306.61, duration about 2.5 hours, depth 0.0005, about 0.8 R_Earth.

EPIC 212009427 known planet, P1=0.775 days, additional object P=0.774 days. slightly out of sync.

EPIC 212035441 looks like contamination, P=0.245175 days.

EPIC 212060250 single dip (maybe extended ring-like source) at BKJD 2339.57

EPIC 212072539 Multiplanet candidate, P1=7.675 days, starting at BKJD 2311.63, duration about 3 hours, depth 0.002. P2=2.787 days, starting at BKJD 2308.33, duration about 2.5 hours, depth 0.0015.

EPIC 212082682 single dip at BKJD 2335.34, duration 13.5 hours, depth 0.0004.

EPIC 212088059 known planet, P=10.365 days, duration about 2.5 hours, depth 0.0017.

EPIC 212092446 single dip at BKJD 2339.2, duration 4.2 hours, depth 0.0001.

EPIC 212114592 maybe transit at BKJD 2309.12 and 2356.79, P=47.68 days, duration 4 hours, depth 0.0002.

EPIC 212160937 probably contamination by some nearby EB, P=0.24515 days, duration about 1 hours.

EPIC 212162232 probably contamination by some nearby EB, P=0.24518 days, duration about 1 hour, various depths around 0 .07.

EPIC 212163353 might be a multiplanet candidate. P1=51.74 days, staring at BKJD 2313.92, duration 4 hours, depth 0.009, P2=5.17 days, starting at BKJD 2308.78, duration 2.5 hours, depth 0.002.

Other:

EPIC 211403356 maybe EB (or more probably contamination by a BGEB) with primary eclipse at BKJD 2308 and seconday eclipse at BKJD 2343.8, duration about 28 hours each.

EPIC 211488010 single dip at BKJD 2339.6, duration 18 hours, depth 0.0003, but star radius 10 R_sol -> object radius 2.3 R_Jupiter -> too large for a planet.

EPIC 211613823 Probably multistellar system, P1=16.673 days, starting at BKJD 2316.13, P2=18.35 days, starting at BKJD 2319.55, P3=21.84 days, starting at BKJD 2307.79, also dip at 2307.2 and more.

EPIC 211745114 Maybe circumbinary planet at BKJD 2320.17, 2337.62, 2352.84, 2368.91. Rougly period around 16.1 days.

EPIC 211806798 It's a LPV R=74.16 R_Sol.

EPIC 211821200 P=0.24525 days, but not all dips fit perfectly. Maybe large TTV's?

EPIC 211953966 maybe EB, single deep dip at BKJD 2316.56.

Posted October 11, 2016 5:01 PM
by ajamyajax

Re 212072539 from Hans Martin's list: and a nice new find with two convincing planet candidates in a small M-dwarf system. These transits are visible in both Andrew's and EVEREST corrected data, although the shorter period transit is more blended in with both. The stellar neighborhood looks fairly clean on Aladin Lite and I saw no paper references yet. 0.47 R_sol estimate. Edit: systematics always some concern with possible short period transits, but still enough here to warrant a re-observation in c16 in my view.

s1=2311.63 p1=7.676 d1=0.09 (2.16 hours +/-)

s2=2308.33 p2=2.787 d2=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)

212072539 , 2MASS J08564852+2130094 , 12.692 , 12.070 , 11.855 , 0.622 , 0.215 , ('K6V', 0.7) , ('M0V',0.58)

au min-max 0.06 0.06

stellar diameter in solar units min-max 0.455 0.49

stellar mass in solar units min-max 0.49 0.49

period in days min-max 7.669 7.669

duration in hours min-max 2.07 2.229

au min-max 0.03 0.03

stellar diameter in solar units min-max 0.445 0.5

stellar mass in solar units min-max 0.465 0.465

period in days min-max 2.783 2.783

duration in hours min-max 1.469 1.651

From NEA, K2 Targets within search area:

EPIC Number RA [decimal degrees] Dec [decimal degrees] Distance [arc sec] Kepler-band [mag] Campaign Number

212072539 134.2022 21.5027 0.0 14.874 5

212071571 134.2356 21.4844 129.72 11.377 5

epic_number,tm_name,ra,dec,k2_teff,k2_rad,k2_mass,k2_kepmag,k2_pmra,k2_pmdec,k2_dist

212072539,2MASS J08564852+2130094,134.202214,21.502674,3787.00,0.36,0.40,14.874,-11.000,10.900, 133.3±44.13

Posted October 13, 2016 4:28 PM
by ajamyajax

Re 211897691 from Ivan's and Hans Martin's lists: a nice K-dwarf system and as mentioned the shorter period transit is already a PC (see papers below). But another transit observed here also looks promising as a planet candidate in both Andrew's and EVEREST corrected data.
My guess is this second transit was also seen by the paper's authors, but omitted because of the quality of the transit. But both prospects seem worth another look in c16, as is the nearby and possibly solitary white dwarf (EPIC 228682373).

s1=2309.495 p1=5.7495 d1=0.11167 (2.68 hours +/-)

s2=2320.005 p2=19.512 d2=0.16792 (4.03 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)

211897691 , 2MASS J08401981+1841344 , 12.796 , 12.295 , 12.173 , 0.501 , 0.122 , ('K3V', 0.81) , ('K3V',0.81)

From NEA, K2 Targets within search area:

EPIC Number RA [decimal degrees] Dec [decimal degrees] Distance [arc sec] Kepler-band [mag] Campaign Number

211897691 130.0826 18.6929 0.0 14.313 5

211896318 130.0933 18.6728 81.09 10.098 5

228682373 130.0554 18.724 145.25 18.020 5, white dwarf

epic_number,tm_name,ra,dec,k2_teff,k2_rad,k2_mass,k2_kepmag,k2_pmra,k2_pmdec,k2_dist

211897691,2MASS J08401981+1841344,130.082557,18.692919,4801.00,0.77,0.82,14.313,2.100,2.800,

EPIC 228682373...

on Simbad, 145.40 arcsecs away, LB 5959 -- White Dwarf, Proper motions mas/yr: -34 -12, Spectral type: DA, 08 40 13.289 +18 43 26.34

"A PSF-based approach to Kepler/K2 data. II. Exoplanet candidates in Praesepe (M 44)"

M. Libralato, D. Nardiello, L. R. Bedin, L. Borsato, V. Granata, L. Malavolta, G. Piotto, P. Ochner, A. Cunial, V. Nascimbeni

https://arxiv.org/abs/1608.00459

"Transiting exoplanet candidates from K2 Campaigns 5 and 6"

Benjamin J. S. Pope, Hannu Parviainen, Suzanne Aigrain

https://arxiv.org/abs/1606.01264

Posted October 14, 2016 5:28 PM
by zoo3hans

EPIC 211529065 seems to have at least two planets.

One with P1=4.4 days.

Another with P2=1.544 days.

Detrended LC used for AKO:

Mark also already commented about this star in the C5 thread. There he suggested a possible 2.315 day period, which is 3/2 * 1.544 , see AKO image below (which is for a period of 2.315 days):

Posted October 17, 2016 8:24 PM
by Dolorous_Edd

Yeah, noted the presence of dips not associated with known pc also

Posted October 17, 2016 8:56 PM
by zoo3hans

EPIC 211413752 is a kown PC with P1=9.328 days. Additional planets with P2=4.528 days (mentioned by Ivan) and P3=26.27 days.

AKO image P1=9.328 days

AKO image P2=4.528 days

AKO image P3=26.27 days

Detrended LC used for AKO:

Posted October 19, 2016 8:05 PM
by Shellface in response to zoo3hans's comment.

(Thank you to zoo3hans for sending me the detrended LC)

The second planet candidate of EPIC 211529065 is not particularly visible in the unphased lightcurve, but folding to the orbital period makes it clearly visible:

The transit depth is 300 ppm, which is only ~twice the standard deviation of the data. Such a weak signal is only detectable due to the large number of transits observed.

The ephemerides for the transits [BJD - 2454833] are:

2306.3273 + 1.5435(n)

2309.9783 + 4.3998(n)

Their period ratio is 2.85, which is far enough from resonance that TTVs are undetectable.

EPIC 211529065 has a spectral type of ~K3, so its radius is about 0.70 Rsol. The companion radii are thus ~1.3 Rearth and ~3.1 Rearth. "b"'s size is rarely detectable by K2, and it is almost certainly terrestrial. "c" is probably comparable to an ice giant, and is not too unusual for a K2 planet.

The star is unfortunately fairly faint (V = 13.8), so mass measurements are unlikely for either planet. Still, validation will be possible, and as a multi-planet system both planets are probably genuine. This should probably be considered for SC, but LC re-observation would be acceptable.

Posted October 21, 2016 9:45 PM
by ajamyajax

https://keplergo.arc.nasa.gov/k2-cycle-5-deadline-fast-approaching.html

Posted October 26, 2016 2:53 PM
by ajamyajax

And although it's not on the recent K2 change list, I compared the c5/c16 crossover targets from the previous k2fov program with the new 6.2 update and got these possible new candidates. Don't know why the difference however (unless changes s/b for campaigns 13,15,16?)...

211399409

211400061

211400364

211400464

211400500

211400563

211401251

211401387

211403836

211403993

211404127

211404501

211404583

211404615

211417185

211398170

211480513

211480703

211480823

211522858

211485094

211485410

211485900

211486258

211464989

211466783

211470238

211470446

211472399

211472437

211474789

211502453

211478531

211566258

211566605

211550405

211567365

211582529

211582818

211568561

211583719

211583906

211551765

211553125

211587617

211555232

211541572

211531168

211681515

211679122

211602578

211617909

211602711

211619407

211637381

211687376

211689453

211690173

211719678

211691611

211682817

211682820

211682976

211725096

211683682

211683799

211684251

211726170

211684709

211685105

211685131

211685267

211685321

211685339

211685644

211686610

211772192

211774296

211745664

211766528

211767058

211767666

211768501

211769229

211769657

211770097

211770197

211826036

211801668

211838767

211802262

211802503

211814505

211803246

211839798

211804644

211804680

211805435

211805460

211887287

211896623

211888372

211890135

211890847

211871208

211892591

211893630

211893894

211894024

211885943

211895406

211895666

211844275

211905228

211941867

211927708

211919635

211928574

211937872

211913330

211921520

211949165

211959869

211959914

211960221

211961041

211961191

211951700

211972744

211973006

211952707

211973228

211973320

211973504

211973710

211974071

211953482

211964709

211974178

211965610

211966140

211966762

211966847

211987231

211987565

211996447

211988318

211997053

212006857

211989128

211989855

211989962

212008262

212016252

211999351

211999656

211999795

211992129

212031230

212073458

212022048

212063191

212063844

212025350

212065771

212066348

212066391

212092746

212082095

212069391

212069935

212020548

212150572

212106947

212154925

212155023

212155026

212155166

212127626

212128500

212128851

212129069

212112639

212134002

212134327

212101222

212149846

228682330

212158804

Posted November 15, 2016 8:32 PM
by Dolorous_Edd

checked EVEREST LC's ( thanks, Mark! ) for new targets

EB's

211999656 - D - period 0.974

211987231 - D - period 17.035

211972744 - D - period 45.904 - third dip at 2317.33? - mentioned by Hans in C5 K2 Finds

Good looking dips

212066391 - at 2350.50

211767666 - looong dip at 2315.407, duration 51.4h, likely processing glitch

211472437 - dips at 2312.16 and 2314.13, and 2347.198

211464989 - dip at 2337.66

Doubtful dips

212129069 - 3 possible dips; at 2314.0 and 2347.198

211999351 - at 2354.79

211582529 - at 2315.09 and 2369.255

Other

211989855 - flares

211989128 - flares

211988318 - flares

211974178 - flares

211973228 - flares

211949165 - HB pulse? at 2342.58, likely processing glitch

211887287 - flares

211885943 - flares

211839798 - flares

211617909 - pulsating variable,

211404127 - periodic variable, likely just spots

Posted November 17, 2016 7:12 AM
by zoo3hans

211417185 maybe P=24.31 days, starting at BKJD 2309.85, duration 4 hours, depth 0.0005.

211767666 to me it looks like a perfect transit, duration about 52.5 days, radius 2.47 R_Earth.

Posted November 17, 2016 7:59 AM
by andrew418

Hi all,

I'm hard at work writing the C14-16 proposal! Quick question: can someone help me out by trying to figure out if there are any non-K2 exoplanet hosts in the C14-16 fields? Like, for example, known transiting hot Jupiters from WASP/HAT/KELT?

If so, please let me know, I appreciate it!

Andrew

Posted December 7, 2016 8:44 PM
by ajamyajax in response to andrew418's comment.

Hi Andrew,

Good news!

About your question, I ran the Archive's confirmed exoplanets table data through the current k2fov program and got these results (and I included the K2 targets just for information's sake).

Basically I can run any RA/Dec lists we come up with through k2fov, so if you think of any other specific mission targets just let me know.

Target RA Declination

c14:

WASP-104,160.602432,7.435026

c15:

HIP 78530,240.481064,-21.980389

K2-38,240.033579,-23.189288

c16:

K2-34,127.57877,22.235908

HD 73534,129.815842,12.960376

HD 75784,133.099747,13.233433

HD 81040,140.946198,20.364454

Pr0211,130.547882,19.277044

NGC 2682 YBP 1194,132.753364,11.814655

NGC 2682 Sand 364,132.48676,11.692484

NGC 2682 YBP 1514,132.753193,11.88653

NGC 2682 YBP 401,132.82936,11.67102

Other interesting targets might be here, considering some of these images might be a bit out-of-date(?):

https://keplergo.arc.nasa.gov/k2-fields.html #c14

If anyone knows where there are RA/Dec lists of all WASP/HAT/KELT targets pls let me know. I will look around also. Mark

Posted December 7, 2016 11:31 PM
by andrew418

Awesome, thanks Mark! I'll add in WASP-104, and then it looks like we've got everything that transits (the M67 planets are being proposed by another group and are nontransiting, we've got K2-34, HD 73534 and 75784 and 81040 are RV planets, so no need for short cadence observations, K2-38 we got, HIP 78530 is directly imaged. Fingers crossed for lots of short cadence!

I think Nexsci should basically have all of the WASP-HAT-KELT planets...
Thanks!
Andrew

Posted December 8, 2016 12:32 AM
by zoo3hans in response to ajamyajax's comment.

I like the ETD at http://var2.astro.cz/ETD/index.php?lang=en&sezona=zima&parent= for WASP/HAT/KELT targets.

Posted December 8, 2016 7:38 AM
by ajamyajax in response to zoo3hans's comment.

Dear Hans Martin, that is an interesting site with a good exoplanet list and user contributions, it seems! I didn't see a way to get a target,ra,dec list there though.

But I did browse through their list manually and looks like nearly every target is already in the Archive table with some having different names (for example the EPICs listed below).

I couldn't find WASP-86/Kelt-12 b or WD 1145+017 b though, so ran the coordinates for those two through k2fov. But neither appears to be in c14, c15, nor c16. But thanks for the nice idea.

EPIC-203771098 b, 16 10 17.69, -24 59 25.19 (K2-24 b)

EPIC-203771098 c, 16 10 17.69, -24 59 25.19 (K2-24 c)

EPIC-210957318 b, 03 29 22.07, +22 17 57.9 (K2-30 b)

EPIC-211089792 b, 04 10 40.955, +24 24 07.35 (K2-29 b)

EPIC-212110888 b, 08 30 18.91, +22 14 09.3 (K2-34 b)

WASP-86/Kelt-12 b, 17 50 33.7, +36 34 12.8

WD 1145+017 b, 11 48 33.63, +01 28 59.4

Posted December 8, 2016 3:48 PM
by zoo3hans in response to ajamyajax's comment.

For a single target, just click on its name and you get its RA/DEC among a lot of other info.

Posted December 9, 2016 7:45 AM
by ajamyajax in response to zoo3hans's comment.

Yes, that's where I got the RA/Dec's posted earlier. But try doing that for fifty or a hundred and you'll see why I was looking for a list.

Posted December 9, 2016 1:00 PM
by ajamyajax

Also to all: I ran RA/Dec lists of KELT_Praesepe data though the k2fov program, and looks like there are a number of overlaps with c5/c16. I'll look at that data and see if we can at least get some continued time series observations for those targets.

Posted December 9, 2016 1:05 PM
by ajamyajax

Of the 66638 KELT_Praesepe (KELTP) targets there are 25240 RA/Dec crossovers visible in c16 per k2fov. Of the 25240 in c16 there are 2787 KELTP targets with light curves that also match the c5 crossovers RA/Decs. There are also 209 periodic level finds by the KELT team (see paper listed below) that could be especially interesting crossover targets. Of these, 21 have c5 EPICs that match the c5/c16 crossover list. I will also post these KELTP c5 crossover data files later when I get a chance, if you want to take a look.

http://iopscience.iop.org/article/10.1088/0004-6256/135/3/907;jsessionid=C87A8D18B279EA41A4A57E5D0F136FCF.c2.iopscience.cld.iop.org

https://www.dropbox.com/s/8kimk17w6iy5vxn/KELTP_c5_c16_interesting_targets.zip?dl=0

Update: here are the 21 periodic level targets that have EPIC c5/c16 crossover matches:

c5 EPIC, KELT identification number, KELT R_K_ band magnitude, Right Ascension in decimal degrees (J2000), Declination in decimal degrees (J2000), ? Period, KELT classification, GCVS/NSV identification or classification

212091090, KP100305, 9.605, 133.03393, 21.84911, none, LPV

211727217, KP100306, 9.606, 131.14550, 16.28497,none, LPV

211918335, KP100445, 9.930, 130.00713, 18.99986, 0.3828, EB, TX Cnc W UMa

211757642, KP100561, 10.149, 130.99077, 16.71554, 1.0438, EB

211914718, KP101231, 11.000, 134.29044, 18.94559, 0.2910, EB

211935518, KP101275, 11.053, 130.47658, 19.25742, 0.8067, Puls

212098045, KP101456, 11.209, 133.22672, 21.98288, 0.4351, Puls

212083250, KP102245, 11.749, 132.76992, 21.70140, 0.5188, EB

211624127, KP102540, 11.894, 130.44375, 14.87345, 0.8213, Puls

211942157, KP102588, 11.916, 132.71335, 19.35729, 1.3244, EB, NSV 04269 V

212116340, KP102811, 12.034, 133.42089, 22.34420, 0.6102, EB

211920022, KP103073, 12.150, 130.02381, 19.02520, 0.8246, Puls

211957146, KP103285, 12.237, 131.47646, 19.58272, 0.3550, EB

211885185, KP103585, 12.345, 131.02744, 18.51100, 4.4082, EB

211918830, KP104317, 12.599, 130.33974, 19.00734, 0.3464, EB

211744244, KP104850, 12.741, 132.90945, 16.52710, none, LPV

211619120, KP105369, 12.877, 130.41766, 14.80151, 11.0424, Puls

211631904, KP110177, 13.760, 130.17535, 14.98393, 0.4420, EB

211728918, KP113453, 14.197, 132.70565, 16.31045, 0.3395, Puls

211732801, KP200312, 10.600, 129.46961, 16.36575, 2.1302, EB

211604396, KP201350, 12.543, 129.40514, 14.59862, 0.8728, EB

Posted December 13, 2016 9:52 PM
by ajamyajax in response to ajamyajax's comment.

Ok, here are the listed c5 crossover KELT files with relative times (saw that KELT_Praesepe began operations in 10/2004). And there are many gaps in this data as shown next, so complete transits could be a bit rare.. Just in case you want to have a look anyway. 😃

https://www.dropbox.com/s/6r3gm8guktjyn5q/KELTP_c5_target_files.zip?dl=0

Data credit: the KELT team as listed in the paper, and the NASA Exoplanet Archive operated by the California Institute of Technology.

Posted December 14, 2016 6:20 PM
by ajamyajax

Re 211942157/KP102588 from the above KELT Praesepe c5/c16 crossover list: just an example of a periodic target in this data.

s1=2307.187 p1=1.32497 d1=0.26 (6.24 hours +/-)

s2=2307.8492 p2=1.32497 d2=0.26 (6.24 hours +/-)

possible primary ephemeris for KELTP data shown..

s1=1.125 p1=1.32497 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)

211942157 , 2MASS J08505120+1921262 , 11.746 , 11.554 , 11.495 , 0.192 , 0.059 , ('F5V', 1.32) , ('F6V',1.25)

From NEA, K2 Targets within search area:

EPIC Number RA [decimal degrees] Dec [decimal degrees] Distance [arc sec] Kepler-band [mag] Campaign Number

211942157 132.7133 19.3573 0.0 12.051 5

epic_number,tm_name,ra,dec,k2_teff,k2_rad,k2_mass,k2_kepmag,k2_pmra,k2_pmdec,k2_dist

211942157,2MASS J08505120+1921262,132.713299,19.357271,7234.00,1.77,1.49,12.051,1.600,-7.900,

From VSX:

Dist. ' Name AUID Coords (J2000) Const. Var. type Period (d) Mag. range

0.00 LL Cnc -- 08 50 51.20 +19 21 26.2 Cnc EA 1.32434 12.02 - 12.48 V

https://www.aavso.org/vsx/index.php?view=detail.top&oid=42893

Listed as V* LL Cnc -- Eclipsing binary of beta Lyr type (semi-detached) on Simbad, Proper motions mas/yr: 1.6 -7.9, 08 50 51.192 +19 21 26.17

Posted December 14, 2016 6:21 PM
by andrew418

Hi all,

The proposal for C14-15 has now been submitted. Thanks so much for all of your hard work on these - we couldn't have done it without you!

Best,
Andrew

Posted December 16, 2016 5:42 AM
by Shellface

I must apologise for not giving much discussion for this proposal; I had little time over the last fortnight, so it was a rush to even get the target list done.

Andrew made the call to have this proposal only include the planets. This is because we ended up proposing a huge number of short cadence targets, which count for 30 long cadence targets each, so it was not feasible to include other targets in the proposal.

Here's a plaintext reproduction of our C16 targets:

EPIC number | cadence | notes

211945201 | short | warm neptune-sized planet host

211682544 | short | long period planet candidate

211901114 | short | Praesepe planet candidate

211969807 | short | Praesepe confirmed planet host

211822797 | short | Praesepe confirmed planet host

211924657 | short | M-dwarf planet candidate, transit timing variations

212110888 | short | confirmed planetary system K2-34

211733267 | short | warm Jupiter candidate

212006344 | short | M-dwarf terrestrial planet candidate around bright star

211913977 | short | Praesepe confirmed planet host

211970147 | short | Praesepe confirmed planet host

211694226 | short | M-dwarf terrestrial planet candidate

212069861 | short | habitable zone planet candidate

211529065 | short | 2 planet system, with terrestrial planet

211413752 | short | 2 planet system, ~2:1 MMR

212009150 | short | M-dwarf planet candidate

211765775 | short | M-dwarf planet candidate, flares

211829796 | long | single-transit planet candidate

211941472 | long | terrestrial planet candidate

211491383 | long | terrestrial planet candidate

211938121 | long | single-transit planet candidate

211711685 | long | single-transit planet candidate

212011230 | long | single-transit planet candidate

211611158 | long | 2 planet system

211743874 | long | planet candidate

211763214 | long | terrestrial planet candidate

211409178 | long | planet candidate

211818195 | long | single-transit planet candidate

212164470 | long | 2 planet system, with terrestrial planet

211825799 | long | single-transit planet candidate

211408522 | long | single-transit planet candidate

211919004 | long | planet candidate

211490999 | long | planet candidate

211816003 | long | planet candidate

211897901 | long | single-transit planet candidate

211904757 | long | single-transit planet candidate

211897691 | long | 2 planet system

211736305 | long | planet candidate

212088059 | long | M-dwarf planet candidate

212072539 | long | M-dwarf 2 planet candidates

212154564 | long | M-dwarf planet candidate

212092746 | long | M-dwarf ultra short period candidate

With 2 SC targets in C15 and WASP-104 in C14 the total number of short cadence targets in the proposal is 20, which is perhaps best described as "ambitious". With 29 further LC targets, this is certainly not a small proposal. However, I am confident in the probability it will be accepted: I believe the choices and justifications for short cadence are sound, and I feel the proposal text Andrew wrote is excellent. We shall be seeing the response sometime soon, anyhow.

Thank you twice over to everyone who contributed; this proposal was quite a task, and it couldn't have been done all of your efforts.

Over the next few weeks I shall be discussing some of the more interesting targets in this thread, for the purposes of making public some comments on their nature.

Posted December 19, 2016 10:31 PM
by ajamyajax

News from the Archive:

December 21, 2016: For our final update of 2016, we offer the following:

New planets! We have added eight new planets, including five new K2 planets discovered in the 800-million-year-old Praesepe (Beehive) cluster. Note the five K2 planets in the Praesepe cluster were previously observed by the KELT-Praesepe survey; find the associated light curves in the new Nearby Object Data section of the the planet's Confirmed Planet Overview page (here's K2-100 b's page, for example).
This week's update brings the total confirmed planet count to 3,439. Click to view the Planet Overview page: HD 30177 c, XO-6 b, EPIC 211990866 b (K2-100 b), EPIC 211913977 b (K2-101 b), EPIC 211970147 b (K2-102 b), EPIC 211822797 b (K2-103 b), EPIC 211969807 b (K2-104 b), and OGLE 2014-BLG-0676L b. Or, see the Confirmed Planets interactive table.

We've also added 121 K2 candidates, bringing the total number of K2 confirmed and candidate objects to 520. View the data in the K2 Candidates interactive table.

If you're attending the AAS conference in Grapevine, Texas the first week of January, stop by the NExScI booth in the exhibit hall and say hello! Project Scientist Jessie Christiansen will also be giving a Hyperwall presentation. (Look for the giant array of television screens.)

Please note the Exoplanet Archive staff will be on a holiday break Dec. 23 through Jan. 2, so responses to Helpdesk tickets and social media may be delayed. We wish you a happy winterval and look forward to serving more new planets in 2017!

http://exoplanetarchive.ipac.caltech.edu/docs/exonews_archive.html #21Dec2016

Posted December 22, 2016 3:28 PM
by Shellface

EPIC 212006344: This is the overlap system of greatest interest to me; I believe it is of high scientific value.

This star is fairly average in brightness for a K2 target (V = 13.15, Kp = 12.5), but it is notably late-type (late-K - early-M) - in fact, it is among the brightest late-type transit hosts known. The stellar colours indicate a spectral type of about K8, corresponding to M ≈ R ≈ 0.62 times solar.

A set of stellar parameters for the star has been recently uploaded to K2FOP by C. Dressing, referring to a Dressing et al. (2017). This has not yet been published, but a literature search turns up this AAS abstract, which I assume refers to the same subject as the upcoming paper. In this case the stellar parameters are spectroscopic, and are better than any I can produce. The values are: Teff = 3993 ± 77 K (SpT = K7), Fe/H = 0.444 ± 0.084 dex, M = 0.630 ± 0.020 Msol, R = 0.591 ± 0.027 Rsol, and log g = 4.694 ± 0.031. These concord with more simple photometric estimates, so I adopt them hereon. The extremely high metallicity is notable; only a couple of percent of stars reach Fe/H = 0.4. Via the Stefan-Boltzmann law I calculate a luminosity L = 0.080 ± 0.013 Lsol, which indicates a distance of about 84 parsecs.

EPIC 212006344 lies in a somewhat busy part of the sky, with 5 additional objects within 60" in the EPIC (3 within 30"). All of these are resolved from the target by K2, however, so the star is not blended at wider ranges. Professional imaging recorded on K2FOP also indicate null detections for closer-in stars, so it seems reasonable to assume the target is not blended.

One of the closest-by stars is EPIC 212006673, a ~2 mag fainter star (Kp = 14.4) which has K2 photometry. Its lightcurve does not show much signal, and it is widely-spaced enough from EPIC 212006344 they do not appear to blend eachother. Curiously, EPIC 212006673 is an M-dwarf with colours indicating a spectral type of M3 ± 1, consistent with a star at the same distance as EPIC 212006344. EPIC 212006673 does not have proper motions in the EPIC, but they are listed on the SDSS and are equal to those of EPIC 212006344 (-6344 has 53.14 ± 7.810 mas/yr at bearing -160.20°, -6673 has 55.03 ± 9.899 mas/yr at bearing -160.91°). Thus the two stars are a co-moving pair composed of a K7 dwarf and an ~M3 dwarf; with an on-sky separation of 20.0" and a distance of ~84 pc, their projected separation is ~1700 AU.

EPIC 212006344's out-of-transit lightcurve shows a rotational period of ~27 days, somewhat short for a late-K dwarf. This rotational period suggests an age of a few Gyr for the system. The rotational period is much longer than the transit period (2.22 days), so they are not related.

I detrended the transit lightcurve and fed it to EXOFAST with priors from the Dressing et al. parameters. The output model is shown below:

And below, a clearer view of the transit profile:

The well-constrained stellar parameters make for well-constrained transit parameters, so the output values are probably reasonably secure.

The transit depth is 433 ± 15 ppm, and assuming δ = (r/R)^2 is valid, r/R = 0.02081 ± 0.00036. With R = 0.591 ± 0.027 Rsol, r = 1.34 ± 0.07 Rearth. The planet is very likely terrestrial; though some planets below r = 1.6 Rearth appear to have substantial atmospheres, this one is hot enough that the lighter volatiles (e.g Hydrogen) must have boiled off. Terrestrial planets are rarely probed by K2, so this is system is very valuable.

As the star is fairly bright, the feasibility of mass measurement is worth considering. Assuming a reasonably optimistic planetary density of 6.5 ± 1.0 g/cm^3 (slightly larger than Earth's), the planetary mass would be 2.84 ± 0.89 Mearth, corresponding to an RV semi-amplitude of 2.0 ± 0.6 m/s.

Would this be detectable with modern instruments? There are not many stars observed with high-precision instruments faint enough for adequate comparison, but a reasonably close analogue is GJ 1132; Berta-Thompson et al. detected the RV signal from GJ 1132 b, with semi-amplitude of 2.76 m/s, at 34% precision with 25 HARPS observations. GJ 1132 is slightly fainter than EPIC 212006344 (GJ 1132 V = 13.49), so the latter's photon noise should be ~15% better than the former's; when additionally considering that EPIC 212006344 is earlier in spectral type (mid-late-M stars essentially have too many spectral lines, which decreases RV precision), then EPIC 212006344 should have ~~25% more precise RVs than GJ 1132, which makes up for the ~30% lower planetary semi-amplitude. Thus, this planet probably is detectable with some semi-dedicated observations. Such observations are certainly warranted, considering the value of mass measurement on a terrestrial planet.

An additional incentive for RV observations is the possibility of the presence of additional planets. Giant planets become rarer towards later spectral types, but the giant planet - metallicity relationship still holds, and with Fe/H = 0.44 EPIC 212006344 is ~5 times more likely to host a giant planet than a similar star with solar metallicity. While the actual probability of a giant planet being present is perhaps around 20%, if one is present then it should be easilydetectable with modern spectrographs.

Overall this is an exceptionally interesting system, and if the proposal goes through the short cadence observations should be greatly rewarding. I advocate aggressive follow-up of this system, which promises to give considerable knowledge on terrestrial planets around late-type stars.

Posted December 23, 2016 11:12 PM