The California-Kepler Survey. II. Precise Physical Properties of 2025 Kepler Planets and Their Host Stars

TL;DR

This paper provides precise stellar and planetary properties for 2025 Kepler planets by combining spectroscopic data with stellar modeling, significantly improving the accuracy of planetary radii and incident flux estimates.

Contribution

It introduces a method that combines spectroscopic constraints with stellar interior modeling to enhance the precision of stellar and planetary parameters.

Findings

Stellar radii constrained to 11%, compared to 40% with photometry.

Planetary radii uncertainties reduced from 42% to 12%.

Incident stellar fluxes computed with 21% precision.

Abstract

We present stellar and planetary properties for 1305 Kepler Objects of Interest (KOIs) hosting 2025 planet candidates observed as part of the California-Kepler Survey. We combine spectroscopic constraints, presented in Paper I, with stellar interior modeling to estimate stellar masses, radii, and ages. Stellar radii are typically constrained to 11%, compared to 40% when only photometric constraints are used. Stellar masses are constrained to 4%, and ages are constrained to 30%. We verify the integrity of the stellar parameters through comparisons with asteroseismic studies and Gaia parallaxes. We also recompute planetary radii for 2025 planet candidates. Because knowledge of planetary radii is often limited by uncertainties in stellar size, we improve the uncertainties in planet radii from typically 42% to 12%. We also leverage improved knowledge of stellar effective temperature to recompute incident stellar fluxes for the planets, now precise to 21%, compared to a factor of two when derived from photometry.