Astronomers are working very hard to confirm the existence of potential exoplanets identified by the Kepler space telescope. One such confirmation was made recently, and it's the "smallest" one yet!
KOI-961 is a red dwarf star. This means that it still has fusion in its core, but it's much smaller than the sun. In fact, it's only 13% the mass of the sun, and is slightly larger than Jupiter in size! The image above shows KOI-961 and its three planets (to scale) next to Jupiter and four of its moons for a comparison of size. KOI-961 was not originally identified by Kepler as having an exoplanetary system. Astronomers from CalTech looked at the public data released by Kepler, and saw something suspicious in the light curve. They observed this star using both the Palomar Observatory and Keck Observatory, and their results confirmed the existence of a 3 planet system! The planets masses are unknown, but their sizes are ~0.57, 0.73 and 0.78 Earth radii. This suggests that they are rocky planets similar in size to Mars. Planets 1 and 2 are too close to the star to harvest life, but planet 3 is just on the inner edge of the habitable zone! Much more work is needed before we can truly speculate the existence of life on this planet, but the more discoveries we make, the better chance we have of finding a planet just like Earth!
Image Credit: CalTech
