2014/12/16 by Will M. Farr, Ilya Mandel, Farr, Will M. +5 · 9 citations
Mathematics · Physics and Astronomy · #Astro and Planetary Science #Astronomy #Astrophysics #Earth and Planetary Astrophysics (astro-ph.EP) #Earth radius #Exoplanet #FOS: Physical sciences #Gamma-ray bursts and supernovae #Logarithm #Mathematics #Orbital period #Physics #Planet #Planetary system #RADIUS #Star (game theory) #Stars #Stellar, planetary, and galactic studies #astro-ph.EP
paper · pdf · doi:10.48550/arxiv.1412.4849
published in arXiv (Cornell University) 29, 2234845 (Cornell University) · Submitted to ApJL
arxiv created 2014/12/16 · openalex publication_date 2014/12/16 · arxiv updated 2014/12/17 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The quantity η_⊕, the number density of planets per star per logarithmic planetary radius per logarithmic orbital period at one Earth radius and one year period, describes the occurrence of Earth-like extrasolar planets. Here we present a measurement of η_⊕ from a parameterised forward model of the (correlated) period-radius distribution and the observational selection function in the most recent (Q17) data release from the Kepler satellite. We find η_⊕ = 3.9-1.6+2.2% (90% CL). We conclude that each star hosts 3.83-0.62+0.76 planets with P \lesssim 3 yr and R \gtrsim 0.2 R_⊕. Our empirical model for false-positive contamination is consistent with the dominant source being background eclipsing binary stars. The distribution of planets we infer is consistent with a highly-stochastic planet formation process producing many correlated, fractional changes in planet sizes and orbits.