Three thousand light-years from Earth sits Kepler 160, a sun-like star that’s already thought to have three planets in its system. Now researchers think they’ve found a fourth. Planet KOI-456.04, as it’s called, appears similar to Earth in size and orbit, raising new hopes we’ve found perhaps the best candidate yet for a habitable exoplanet that resembles our home world. The new findings bolster the case for devoting more time to looking for planets orbiting stars like Kepler-160 and our sun, where there’s a better chance a planet can receive the kind of illumination that’s amenable to life.
Most exoplanet discoveries so far have been made around red dwarf stars. This isn’t totally unexpected; red dwarfs are the most common type of star out there. And our main method for finding exoplanets involves looking for stellar transits—periodic dips in a star’s brightness as an orbiting object passes in front of it. This is much easier to do for dimmer stars like red dwarfs, which are smaller than our sun and emit more of their energy as infrared radiation. The highest-profile discovery of this type is near our closest neighboring star, Proxima Centauri—a red dwarf with a potentially habitable planet called Proxima b (whose existence was, incidentally, confirmed in a new study published this week).
Data on the new exoplanet orbiting Kepler 160, published in Astronomy and Astrophysics on Thursday, points to a different situation entirely. From what researchers can tell, KOI 456.04 looks to be less than twice the size of Earth and is apparently orbiting Kepler-160 at about the same distance from Earth to the sun (one complete orbit is 378 days). Perhaps most important, it receives about 93% as much light as Earth gets from the sun.