KIC 7944566 Unlisted Eclipsing Binary

KIC 7944566 in Q7

Planet Hunters forum Talk members have flagged this transit for KIC 7944566 as an unlisted eclipsing binary star system. It shows up in both Kepler quarters Q7 and Q12. Not listed in Kepler Threshold Crossing Events (TCE) table.

UKIRT

You can follow this system on Talk here

Long Period Unlisted Eclipsing Binary - KID 7971363

KID 7971363 is an unlisted eclipsing binary star system flagged by Planet Hunters forum Talk members in Q7.

Kian Jek:

If the primary stellar data is accurate, we're looking at a 0.24x Sol companion, 26x RE, too large to be a brown dwarf. Let's hope we see a primary eclipse soon, but the eclipse duration of ~37.75 hr means a very long period > 10 years!

 You can follow this eclipsing binary here.

Those Tricky Unlisted Eclipsing Binary Stars

One would think it would be easy finding unlisted eclipsing binary (UEB) star systems by visually examining the Kepler light curves at Planet Hunters and then comparing the star data with a published eclipsing binary stars catalog. Here is an example of a detached eclipsing binary that was flagged by Planet Hunters forum Talk members back in December of 2011 for KID 4586468:

In order to be placed with Planet Hunters UEB candidates three transits drops must be observed through the quarters. The third transit drop was identified in Q9. All looks well except that this star is not part of an eclipsing binary star system. The real UEB is associated with KID 4586482.

Kian Jek:

APOs seen and vector plotted below. Contaminated by star #2, KID 4586482, which is the actual eclipsing binary  (an unlisted eclipsing binary) with a period of 623d.






You can follow the real eclipsing binary star system here.


Often light curve contamination of stars by background eclipsing binaries (BGEB) form strange patterns that cue Planet Hunters members to dig deeper. This is the light curve for KID 5791875 posted in October of 2011:

Click here for more detailed view of visual cue- the vertical and spaced light bars.

The next step is to run a phased curve for the light curve looking for the tell that it is an EB. In this case the phased curve shows a rough, but good image for an over contact eclipsing binary (OCEB):

Data from NASA Exoplanet Archive.

Kian Jek:

This curve is extremely noisy and the eclipses are very shallow - after some processing and detrending, this is the best I can do:




With the rounded tops and sharper alternating minimas it certainly looks like an OC EB, but the depths of the minimas are just 0.04%. It's possible that this is due to flux dilution. There is a brighter star nearby which has no periodicity, in fact it is a pulsating giant:


 

Data from NASA SkyView

Veteran forum Talk member Daryll LaCourse completed the analysis using PYKE and identified the real OCEB as star #2:


Source appears to lie in the direction of star #2 (KIC 5791886):



FULL
Flipped and rotated:


KIC 5791886 has a Q4-Q9 light curve on record and is obviously an EB but does not appear to be slated for inclusion in the Prsa catalog as yet:

Kian Jek:

Wow, that's a nice find, Daryll. 5791886 is definitely the real EB here, it's not even in v3, so it must be a new UEB:



Very nice, clean phased curve with deep eclipses. Note how the period matches that of KID 5791875.

You can follow the UEB here.

KIC 2581316 - Unlisted Planet Candidate or Eclipsing Binary?

Planet Hunters forum Talk members flagged this transit for KIC 2581316 around May of 2011. There are now four observed transits through quarter 9 in the released Kepler data set. It appears that this transit was originally flagged as a false positive, but no longer appears on that list. The star has a magnitude of 11.69.

Q9 time plot

Here is Kian Jek's comment:

"From the profile it looks like a classic planetary transit, and may not be an EB after all - rapid drop offs, with a clustering of data points at a U-shaped bottom. Unfortunately we don't know the radius of the star."

Here is Daryll Lacourse's comment on Keppixseries below:

"July released target pixel files for KIC 2581316; the transits/eclipses seem visible and included within the large optimal aperture masks in each case. Contamination does not seem to be involved."

Full view

 Full view

Visit the Planet Hunters forum Talk page for more information on this transit here.

KIC 10074700 Unlisted Eclipsing Binary with One Year Period

KIC 10074700 is an unlisted detached eclipsing binary star system identified by Planet Hunters forum Talk members with a one year period.

KID 5217733 Eclipsing Binary Super Contaminator

One of the obstacles to analyzing Kepler light curves is ruling out light contamination in the target star from background stars. Background eclipsing binary stars (BG EBs) are a real problem. KID 5217733 is a detached eclipsing binary star system with a magnitude of 7.4. This is a very bright star and as Kian Jek says, is a "Super Contaminator" affecting many nearby stars in the area.

Read more on this star on the Talk thread here.

KIC 8308347 - Unlisted Eclipsing Binary at Planet Hunters

Quarter 5 light curve for KIC 8308347

Phased curve by Kian Jek:

 

More information here.