Norio Narita

Abstract The Galaxy’s most common known planetary systems have several Earth-to-Neptune-size planets in compact orbits1. At small orbital separations, larger planets are less common than their smaller counterparts by an order of magnitude. The young star V1298 Tau hosts one such compact planetary system, albeit with four planets that are uncommonly large (5 to 10 Earth radii)2,3. The planets form a chain of near-resonances that result in transit-timing variations of several hours.

Abstract Planet formation models indicate that the formation of giant planets is substantially harder around low-mass stars due to the scaling of protoplanetary disc masses with stellar mass. The discovery of giant planets orbiting such low-mass stars thus imposes strong constraints on giant planet formation processes. Here we report the discovery of a transiting giant planet orbiting a 0.207 ± 0.011 M⊙ star.