The Core Accretion Model Predicts Few Jovian-Mass Planets Orbiting Red Dwarfs

Abstract

The favored theoretical explanation for giant planet formation -- in both our\nsolar system and others -- is the core accretion model (although it still has\nsome serious difficulties). In this scenario, planetesimals accumulate to build\nup planetary cores, which then accrete nebular gas. With current opacity\nestimates for protoplanetary envelopes, this model predicts the formation of\nJupiter-mass planets in 2--3 Myr at 5 AU around solar-mass stars, provided that\nthe surface density of solids is enhanced over that of the minimum-mass solar\nnebula (by a factor of a few). Working within the core-accretion paradigm, this\npaper presents theoretical calculations which show that the formation of\nJupiter-mass planets orbiting M dwarf stars is seriously inhibited at all\nradial locations (in sharp contrast to solar-type stars). Planet detection\nprograms sensitive to companions of M dwarfs will test this prediction in the\nnear future.\n