Spherically symmetric model stellar atmospheres and limb darkening II: limb-darkening laws, gravity-darkening coefficients and angular diameter corrections for FGK dwarf stars

TL;DR

This paper provides new limb-darkening and gravity-darkening coefficients, along with angular diameter corrections, for FGK dwarf stars based on spherically symmetric stellar atmosphere models, improving the accuracy of observational interpretations.

Contribution

It extends previous work on giant stars by applying spherically symmetric models to FGK dwarf stars, highlighting the importance of sphericity in modeling stellar atmospheres.

Findings

Sphericity significantly affects limb-darkening coefficients for dwarf stars.

New coefficients improve modeling of planetary transits and interferometry.

Differences between spherical and plane-parallel models are substantial.

Abstract

Limb darkening is a fundamental ingredient for interpreting observations of planetary transits, eclipsing binaries, optical/infrared interferometry and microlensing events. However, this modeling traditionally represents limb darkening by a simple law having one or two coefficients that have been derived from plane-parallel model stellar atmospheres, which has been done by many researchers. More recently, researchers have gone beyond plane-parallel models and considered other geometries. We previously studied the limb-darkening coefficients from spherically symmetric and plane-parallel model stellar atmospheres for cool giant and supergiant stars, and in this investigation we apply the same techniques to FGK dwarf stars. We present limb-darkening coefficients, gravity-darkening coefficients and interferometric angular diameter corrections from Atlas and SAtlas model stellar atmospheres. We find that sphericity is important even for dwarf model atmospheres, leading to significant differences in the predicted coefficients.