Planet Masses, Radii, and Orbits from NASA's K2 Mission

TL;DR

This paper presents a comprehensive catalog of 86 exoplanets from NASA's K2 mission, detailing their masses, sizes, and orbits, based on uniform analysis of photometry and Doppler measurements, facilitating statistical exoplanet studies.

Contribution

It provides a uniform analysis pipeline and a new dataset of stellar and planetary parameters for 86 exoplanets, enhancing the reliability of statistical exoplanet research.

Findings

81 planets discovered via transits in K2 data

32 planets have Doppler signals >5-sigma

Planet sizes range from Earth-sized to larger than Jupiter

Abstract

We report the masses, sizes, and orbital properties of 86 planets orbiting 55 stars observed by NASA's K2 Mission with follow-up Doppler measurements by the HIRES spectrometer at the W. M. Keck Observatory and the Automated Planet Finder at Lick Observatory. Eighty-one of the planets were discovered from their transits in the K2 photometry, while five were found based on subsequent Doppler measurements of transiting planet host stars. The sizes of the transiting planets range from Earth-size to larger than Jupiter (1-3 REarth is typical), while the orbital periods range from less than a day to a few months. For 32 of the planets, the Doppler signal was detected with significance greater than 5-sigma (51 were detected with >3-sigma significance). An important characteristic of this catalog is the use of uniform analysis procedures to determine stellar and planetary properties. This includes the transit search and fitting procedures applied to the K2 photometry, the Doppler fitting techniques applied to the radial velocities, and the spectral modeling to determine bulk stellar parameters. Such a uniform treatment will make the catalog useful for statistical studies of the masses, densities, and system architectures of exoplanetary systems. This work also serves as a data release for all previously unpublished RVs and associated stellar activity indicators obtained by our team for these systems, along with derived stellar and planet parameters.