On the Exomoon Population in Kepler, and the Exomoon Candidate Kepler-1625b I
Recent work by the Hunt for Exomoons with Kepler (HEK) collaboration suggests that moons are rare in exoplanetary systems between ~0.1 and 1 AU. This result appears to be consistent with theoretical studies suggesting that moons will be lost through dynamical processes as giant planets migrate inward. As such, the dearth of exomoons at small semimajor axes could be viewed as observational evidence of planetary migration. We present an overview of our work characterizing the population of exomoons in the Kepler data, and discuss our recent Hubble Space Telescope observations of the exomoon candidate Kepler-1625b I.