Kepler Planet Masses and Eccentricities from TTV Analysis

TL;DR

This study analyzes transit timing variations of 145 Kepler planets to determine their masses and eccentricities, providing new measurements and insights into planetary compositions and orbital dynamics.

Contribution

It introduces a uniform analysis using two methods to measure planet masses and eccentricities, including new measurements for previously uncharacterized planets.

Findings

49 planets have robust mass measurements, including 12 new ones.

Planet eccentricities are generally small, around a few percent.

Analytic TTV formulas help reduce degeneracies in eccentricity estimates.

Abstract

We conduct a uniform analysis of the transit timing variations (TTVs) of 145 planets from 55 Kepler multiplanet systems to infer planet masses and eccentricities. Eighty of these planets do not have previously reported mass and eccentricity measurements. We employ two complementary methods to fit TTVs: Markov chain Monte Carlo simulations based on N-body integration and an analytic fitting approach. Mass measurements of 49 planets, including 12 without previously reported masses, meet our criterion for classification as robust. Using mass and radius measurements, we infer the masses of planets' gaseous envelopes for both our TTV sample as well as transiting planets with radial velocity observations. Insight from analytic TTV formulae allows us to partially circumvent degeneracies inherent to inferring eccentricities from TTV observations. We find that planet eccentricities are generally small, typically a few percent, but in many instances are non-zero.