Planetary Mass Determinations from a Simplified Photodynamical Model -- Application To The Complete Kepler Dataset

TL;DR

This paper introduces a simplified photodynamical model that accurately determines planetary masses from Kepler data, including new measurements for small, low-TTV planets, demonstrating the method's effectiveness for future missions.

Contribution

The paper presents a minimal-degree-of-freedom photodynamical model that reliably estimates planetary masses, reducing errors and enabling new mass determinations for small exoplanets.

Findings

Successfully analyzed 64 Kepler systems with 218 planets.

Determined significant masses for 88 planets, including 23 new measurements.

Reduced mass estimation errors by approximately 22% for known planets.

Abstract

We use PyDynamicaLC, a model using the least number of, and the least correlated, degrees of freedom needed to derive a photodynamical model, to describe some of the smallest -- and lowest TTV (transit timing variations) amplitude -- of the Kepler planets. We successfully analyze 64 systems containing 218 planets, for 88 of which we were able to determine significant masses (to better than $3\sigma$). We demonstrate consistency with literature results over two orders of magnitude in mass, and for the planets that already had literature mass estimations, we were able to reduce the relative mass error by $\sim22\%$ (median value). Of the planets with determined masses 23 are new mass determinations with no previous significant literature value, including a planet smaller and lighter than Earth (KOI-1977.02 / Kepler-345 b). These results demonstrate the power of photodynamical modeling with the appropriately chosen degrees of freedom. This will become increasingly more important as smaller planets are detected, especially as the TESS mission gathers ever longer-baseline light curves and for the analysis of the future PLATO mission data