KID 202071505 (APH00008i0 ) - eclipsing binary with outbursts
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by TED91
From the light curve of KID 202071505 it looks like it's a binary system (P=3.5 days). There are also some outbursts. I wonder what causes those outbursts. Is it caused by the some interaction between the stars?
https://www.cfa.harvard.edu/~avanderb/k2c0/ep202071505.html
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by Gingerion
Hello. Could be that the total luminosity is changing due to stars tugging eachother. As it is visible from the lightcurve one star is faster .
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by ajamyajax
Sure looks that way. And could be the point where these two stars in an eccentric orbit are closest to each other (called periastron I believe).
You can read more about this in general here on Spica's wiki page. That system, which is easily visible in the northern hemisphere skies, was discussed on NPR radio in the states today which is why I looked it up.
https://en.wikipedia.org/wiki/Spica
More on EPIC 202071505, P=3.5554582 days
"Kepler Eclipsing Binary Stars. VI. Identification of Eclipsing Binaries in the K2 Campaign 0 Data-set"
http://arxiv.org/abs/1503.0182920207150510.1099.2912516.109360.313.5554581942.7771TYC1329-1160-1;2MASS06370987+1606445 (the 2mass needs fixed in the paper however)
http://keplerebs.villanova.edu./overview/?k=202071505
Listed as TYC 1329-1160-1 -- Star on Simbad, 06 37 09.9007 +16 06 33.691
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by ajamyajax
Also saw somewhere that Spica might have more than two stars... Maybe 202071505 does also? Speculative, but the secondary transit seems to show a binary pair with an alternating fit.
s1=1939.22 p1=3.5554582 d1=0.1625 (3.9 hours +/-) <-- ~6.02% flux reduction
s2=1940.342 p2=3.5554582 d2=0.1333 (3.2 hours +/-) <-- ~3.66% flux reductionau min-max 0.045 0.055
stellar diameter in solar units min-max 1.245 1.61
stellar mass in solar units min-max 0.96 1.765
period in days min-max 3.546 3.561
duration in hours min-max 3.503 3.7au min-max 0.045 0.055
stellar diameter in solar units min-max 1.105 1.435
stellar mass in solar units min-max 0.96 1.765
period in days min-max 3.546 3.561
duration in hours min-max 3.102 3.299
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by Gingerion
Thanks for the info 😃 Could be that the stars get stretched or some weird solar winds add up when they are near periastron. The smaller companion definatley picks up speed.
The lightcurve between small and big transit is not flat, but flattened and streched-out parabola, and between the big and small transit is a staight up thin parabola.
Could this be a sign of some weird resonance between the two stars ? or a change of angle at wich we view the binary system?As for the possible third companion star... hmm could be .. If we look at the lightcurve of the two main stars as a flat line of A+B , and ignore their respective eclipses , those parabolas look like they have some aspect ratio between them like 1:4 . Maybe the star C is under some weird angle and pops out into view inbetween the eclipses.
Yeah, too many unknowns, but that is what drives us to find out more and stay curious 😃
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by Gingerion
playing around with this 😃
http://astro.unl.edu/naap/ebs/animations/ebs.html
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