Spherically symmetric model stellar atmospheres and limb darkening

II. Limb-darkening laws, gravity-darkening coefficients and angular diameter corrections for FGK dwarf stars^⋆

¹ Department of Physics & AstronomyEast Tennessee State University, Box 70652 Johnson City, TN 37614, USA
e-mail: neilsonh@etsu.edu
² Department of Chemical and Physical Sciences, University of Toronto Mississauga, 3359 Mississauga, Ontario, L5L 156, Canada
³ Department of Astronomy & Astrophysics, University of Toronto, Toronto, Ontario, MSS 3H4, Canada
e-mail: lester@astro.utoronto.ca

Received: 13 May 2013
Accepted: 24 June 2013

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.