Modal Decomposition of TTV - Inferring Planet Masses and Eccentricities

TL;DR

This paper introduces a new, efficient linear decomposition method for inferring exoplanet masses and eccentricities from transit timing variations, simplifying the analysis process compared to traditional numerical searches.

Contribution

The authors develop a novel linear mode-based approach to invert TTV signals, reducing computational complexity and enabling easier extraction of planetary parameters.

Findings

Successfully inferred masses and eccentricities of 6 Kepler planets

Demonstrated the method's effectiveness on real TTV data

Provided insights into the physical properties of transiting exoplanets

Abstract

Transit timing variations (TTVs) are a powerful tool for characterizing the properties of transiting exoplanets. However, inferring planet properties from the observed timing variations is a challenging task, which is usually addressed by extensive numerical searches. We propose a new, computationally inexpensive method for inverting TTV signals in a planetary system of two transiting planets. To the lowest order in planetary masses and eccentricities, TTVs can be expressed as a linear combination of 3 functions, which we call the \textit{TTV modes}. These functions depend only on the planets' linear ephemerides, and can be either constructed analytically, or by performing 3 orbital integrations of the three-body system. Given a TTV signal, the underlying physical parameters are found by decomposing the data as a sum of the TTV modes. We demonstrate the use of this method by inferring the mass and eccentricity of 6 \textit{Kepler} planets that were previously characterized in other studies. Finally we discuss the implications and future prospects of our new method.