Journal Article

Occurrence and Mass Distribution of Close-in Super-Earths, Neptunes, and Jupiters

Howard, Andrew W, Marcy, Geoffrey W, Isaacson, Howard, Johnson, John Asher, Ida, Shigeru, Valenti, Jeff A, Wright, Jason T, Fischer, Debra A, Anderson, Jay, Lin, Doug N.C

2010

Overview

The questions of how planets form and how common Earth-like planets are can be addressed by measuring the distribution of exoplanet masses and orbital periods. We report the occurrence rate of close-in planets (with orbital periods less than 50 days), based on precise Doppler measurements of 166 Sun-like stars. We measured increasing planet occurrence with decreasing planet mass (M). Extrapolation of a power-law mass distribution fitted to our measurements, df/dlogM = 0.39 M⁻⁰.⁴⁸, predicts that 23% of stars harbor a close-in Earth-mass planet (ranging from 0.5 to 2.0 Earth masses). Theoretical models of planet formation predict a deficit of planets in the domain from 5 to 30 Earth masses and with orbital periods less than 50 days. This region of parameter space is in fact well populated, implying that such models need substantial revision.

• Publisher: American Association for the Advancement of Science,The American Association for the Advancement of Science
• Subject: Astronomy / Astrophysics / Average linear density / Doppler effect / Earth / Earth, ocean, space / Exact sciences and technology / Extrapolation / Extrasolar planetary systems / Extrasolar planets / Mass distribution / Mathematical models / Measurement techniques / Neptune / Orbitals / Orbits / Planet formation / Planetary orbits / Planets / Star & galaxy formation / Stars / Stellar orbits / Substellar companions ; planets / Terrestrial planets