A planet like Kepler-296f is bound to get a lot of publicity. Orbiting a star half the Sun’s size and only five percent as bright, this world, twice the size of the Earth, appears to orbit in the habitable zone, where liquid water could exist on its surface. We focus so much on the potential of life that the four planets announced yesterday (out of 715 newly verified worlds) inevitably get special treatment. And we learn that Kepler-296f exists in a system with four other planets, orbiting the star every thirty days. What we don’t know is whether we’re dealing with a small Neptune-class world surrounded by a thick hydrogen/helium atmosphere or a water world with a deep ocean.
An interesting world, to be sure, but the real story in yesterday’s announcements from the Kepler team has to do with the ‘verification by multiplicity’ technique used to validate the existence of so many planets in 305 star systems. One of the findings papers titled “Almost All of Kepler’s Multiple Planet Candidates are Planets” (to be published March 10 in The Astrophysical Journal) makes the case that the vast majority of Kepler’s multiple planet candidates are true multi-planet systems, the number of false positives lower for multiples than for single detections.