Gravity-darkening exponents for MESA stellar evolution models

TL;DR

The paper addresses gravity-darkening exponents $β$ across stellar evolution and the need for continuous, model-consistent values along entire tracks. It uses the triangle strategy with MESA v7385, adopting $X=0.70$, $Z=0.02$, A09 opacities, and $α_{\rm MLT}=1.84$, to compute $β$ from the ZAMS to the giant phase for ten initial masses. The main result is a self-consistent set of $β$ values along evolutionary tracks, updating earlier Claret values derived from older models. The work supports improved interpretation of light curves in eclipsing binaries and rapidly rotating exoplanet host stars, and the data are publicly available electronically with accompanying stellar parameters such as $\log L$, $\log g$, $\log T_{\rm eff}$, and current mass.

Abstract

In this Research Note we present new gravity-darkening exponents ($β$) for several stellar evolution models from the ZAMS up to the giant phase. The models were computed using the MESA code (version 7385) for the composition $X = 0.70$ and $Z = 0.02$, adopting A09 opacities and a mixing length parameter of $α_{\rm MLT} = 1.84$. Results were calculated using the triangle strategy, for initial stellar masses of 1.0, 1.5, 2.0, 2.5, 3.0, 5.0, 7.0, 10.0, 15.0, and 20.0 $M_{\odot}$, and provide an update on previously available $β$ values that used older models.