Model-Independent Stellar and Planetary Masses from Multi-Transiting Exoplanetary Systems

TL;DR

The paper introduces a new method combining transit timing variations and radial velocity data to directly measure stellar and planetary masses in multi-transiting systems, especially useful for stars where spectral methods are challenging.

Contribution

It presents an analytical technique to determine masses in multi-transiting exoplanet systems near mean-motion resonances, validated through simulations and applicable to upcoming bright star surveys.

Findings

Method accurately estimates masses in simulated systems.

Identifies eight systems suitable for application with follow-up RV data.

Optimal for bright stars targeted by future missions like TESS or PLATO.

Abstract

Precise exoplanet characterization requires precise classification of exoplanet host stars. The masses of host stars are commonly estimated by comparing their spectra to those predicted by stellar evolution models. However, spectroscopically determined properties are difficult to measure accurately for stars that are substantially different from the Sun, such as M-dwarfs and evolved stars. Here, we propose a new method to dynamically measure the masses of transiting planets near mean-motion resonances and their host stars by combining observations of transit timing variations with radial velocity measurements. We derive expressions to analytically determine the mass of each member of the system and demonstrate the technique on the Kepler-18 system. We compare these analytic results to numerical simulations and find the two are consistent. We identify eight systems for which our technique could be applied if follow-up radial velocity measurements are collected. We conclude this analysis would be optimal for systems discovered by next generation missions similar to TESS or PLATO, which will target bright stars that are amenable to efficient RV follow-up.