A Universal Break in the Planet-to-star Mass-ratio Function of MKG Stars
AffiliationUniv Arizona, Lunar & Planetary Lab
MetadataShow full item record
PublisherIOP PUBLISHING LTD
CitationIlaria Pascucci et al 2018 ApJL 856 L28
JournalASTROPHYSICAL JOURNAL LETTERS
Rights© 2018. The American Astronomical Society. All rights reserved.
Collection InformationThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at firstname.lastname@example.org.
AbstractWe follow the microlensing approach and quantify the occurrence of Kepler exoplanets as a function of planet-to-star mass ratio, q, rather than planet radius or mass. For planets with radii similar to 1-6 R-circle plus and periods <100 days, we find that, except for a normalization factor, the occurrence rate versus q can be described by the same broken power law with a break at similar to 3 x 10(-5) independent of host type for hosts below 1 M-circle dot. These findings indicate that the planet-to-star mass ratio is a more fundamental quantity in planet formation than planet mass. We then compare our results to those from microlensing for which the overwhelming majority satisfies the M-host < 1 M-circle dot criterion. The break in q for the microlensing planet population, which mostly probes the region outside the snowline, is similar to 3-10 times higher than that inferred from Kepler. Thus, the most common planet inside the snowline is similar to 3-10 times less massive than the one outside. With rocky planets interior to gaseous planets, the solar system broadly follows the combined mass-ratio function inferred from Kepler and microlensing. However, the exoplanet population has a less extreme radial distribution of planetary masses than the solar system. Establishing whether the mass-ratio function beyond the snowline is also host type independent will be crucial to build a comprehensive theory of planet formation.
VersionFinal published version
SponsorsNASA Science Mission directorate; National Aeronautics and Space Administration [NNX15AD94G]; NASA's Science Mission Directorate