Forgotten Kepler Planet Candidate Orbits Triple-Star System

by | Jan 13, 2021 | AAS, Daily Space, Exoplanets | 0 comments

Forgotten Kepler Planet Candidate Orbits Triple-Star System
IMAGE: This illustration shows the planet KOI-5Ab transiting across the face of a Sun-like star, which is part of a triple-star system located 1,800 light-years away in the Cygnus constellation. CREDIT: Caltech/R. Hurt (Infrared Processing and Analysis Center, or IPAC

In new research presented at the AAS meeting, researchers present a follow-up on KOI-5Ab, the second potential planet discovered by Kepler. 

First spotted in 2009, this system clearly had something going on, but exactly what … well the data was a mess, and this object was set aside. By 2014, researchers were able to say, thanks to follow-up observations with the Keck and Gemini North telescopes, that if KOI-5Ab is a planet, it orbits a triple star system. The data was still too messy to confirm a planet, however. 

In 2018, the TESS mission just happened to have this weird system in its field of view. With its more sensitive systems, it was able to tease out just what is going on: this system has at least one planet, KOI-5Ab, that is orbiting the largest star in a triple system. This particular system consists of two larger stars, KOI-5A and B, that orbit together like a binary star, and this pair is in turn orbited by a smaller star, KOI-5C. Like nesting wheels, the planet orbits its star roughly every five days, the inner stars orbit one another every thirty years, and the third star orbits the pair every 400 years.

This work was presented by David Ciardi, who admits, KOI-5Ab fell off the table and was forgotten. If it weren’t for TESS looking at the planet again, I would never have gone back and done all this detective work.

This research points out that our powerful suite of space telescopes are returning a wealth of data that over and over again are able to produce new science long beyond the end of their missions. The universe is complicated, and understanding everything we see just takes time.

More Information

Caltech press release 

NASA press release 


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