Known Eclipsing Binary with Unknown Third Body KID 11519226

Planet Hunters forum Talk member troyw has identified transit timing variations (TTVs) in a known eclipsing binary star system KID 11519226 using his Amateur Kepler Obvservatory (AKO) program. The TTVs indicate a third orbiting body associated with this system.

troyw:

This star system shows TTVs for both the primary and secondary sets of transits. The published period is 22.1745d, but the data started being collected during a prominent swing in the TTVs, throwing off the period slightly. A more accurate period looks like 22.162d.
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Note the change in the black horizontal line indicating the TTVs.

Kian Jek:

Nice find, Troy! The profile of the TTVs for the primary and the secondary eclipses are not quite the inverse of each other, as the curve-fits are slightly different in the O-C plot:




You can follow this eclipsing star system with an unknown third orbiting body here.

Timing Is Everything

I have a quickly growing appreciation for the importance of TTV (transit timing variations) with respect to the study of extra solar planets and Kepler data in general. TTV studies have been at the forefront of Kepler research for well over a year now, revealing the presence of additional non transiting partners to confirmed exoplanets and offering us powerful new insights into the formation history and dynamical interactions within these star systems. Particularly important benchmark systems can be found detailed in the great seven part series "Transit Timing Observations From Kepler"  (available on ArXiv.org), in the recent submitted paper "Kepler 36: A Pair Of Planets With Neighboring Orbits And Dissimilar Densities", (displayed in header image) and a host of other multi-candidate system studies available in the current literature.

Planetary bodies are not the only objects subject to the tug of a neighbor. We know that the same laws of physics apply everywhere (at least at this point in the history of the Universe!) and we also know that many systems are in fact double star or binary configurations, something that perhaps makes our own home neighborhood a little more noteworthy being it lacks a such a stellar companion. While less common than binaries, triple (trinary) or greater arrangements are very possible and well known in the current literature; as many as 20% of binaries may host a third companion object. Where our viewing angle allows for eclipses, we have means to measure eclipse timing variations in similar manner to TTV's. One well known example in the current Kepler catalog takes the form of KOI-126, an eclipsing pair of M-dwarfs in orbit around an F class star.

Since the Q7-Q9 Kepler data release, additional targets of interest displaying tertiary eclipses and timing variations have been noted by PH users. The first is found at (KIC 5255552): a ~15 K-magnitude target with new anomalous eclipses visible in Quarter 7, suggesting a companion object to a detached binary pair which is itself in a ~34 day period. This companion appears to be known to the Kepler Science team already, although it has yet to be fully modeled and characterized with the available dataset.

O-C diagram for 5255552:

The second case was first noted earlier this year on PH Talk and appears to be a new trinary candidate; it exhibits obvious tertiary eclipses at target KIC 6964043 and preliminary O-C diagrams and plots show some amazing variations that can be measured not on the order of seconds or minutes--but hours!

Jeff L. Coughlin of New Mexico State University stopped by PH Talk and offered his suspicions that this system may best be explained as: "...a G5V star in a 238 day eccentric orbit around a pair of 10.7 day eclipsing M3V+M4V stars, all eclipsing each other."

Some further discussion can be found here.

Plots courtesy of Kian Jek and Jeff Coughlin. 
Banner image credit:  NASA; Frank Melchior, frankacaba.com; Eric Agol