After NASA's Kepler mission identified hundreds of new exoplanets, astronomer Benjamin J. Fulton refined the data and identified two clear peaks in exoplanet sizes, separated by a "radius gap" where planets are much scarcer. These data continue to inform new studies. (Values for planets below 1.2 Earth radii are omitted because of poor data quality.)(Source: "The California-Kepler Survey. VII. Precise Planet Radii Leveraging Gaia DR2 Reveal the Stellar Mass Dependence of the Planet Radius Gap," by Benjamin J. Fulton and Erik A. Petigura, in Astronomical Journal, Vol. 156, No. 6; November 2018 (data) )