How common are sub-Neptune exoplanets in the Milky Way?
They’re pretty common. One really fantastic result from NASA’s Kepler Space Telescope was that these small planets – and when I say small, I arbitrarily mean smaller than Neptune – tend to be very common in the Milky Way, at least out to periods that we have been able to probe, so about 50 days. In that sense a planet the size of this one is not very uncommon. A really nice thing is that these exoplanets are really close to us and we can study them, but we know that they’re pretty common thanks to Kepler, and we’re waiting for one that is close enough that we can actually learn a bit more about it.
Diana Dragomir is a Hubble fellow at the Massachusetts Institute of Technology’s Kavli Institute for Astrophysics and Space Research