Limb-darkening coefficients from line-blanketed non-LTE hot-star model atmospheres

TL;DR

This paper provides extensive limb-darkening coefficients derived from non-LTE, line-blanketed hot-star models across a wide range of stellar parameters and photometric systems, useful for precise stellar observations.

Contribution

It introduces new grids of limb-darkening coefficients from non-LTE models for hot stars, covering various metallicities and passbands, with analysis of parameter sensitivities.

Findings

Limb darkening weakly depends on metallicity.

Limb darkening strongly varies with surface gravity.

Comparison shows differences between LTE and non-LTE models.

Abstract

We present grids of limb-darkening coefficients computed from non-LTE, line-blanketed TLUSTY model atmospheres, covering effective-temperature and surface-gravity ranges of 15--55kK and 4.75 dex (cgs) down to the effective Eddington limit, at 1x, 1x, 0.5x (LMC), 0.2x (SMC), and 0.1x solar. Results are given for the Bessell UBVRIJKHL, Sloan ugriz, Stromgren ubvy, WFCAM ZYJHK, Hipparcos, Kepler, and Tycho passbands, in each case characterized by several different limb-darkening `laws'. We examine the sensitivity of limb darkening to temperature, gravity, metallicity, microturbulent velocity, and wavelength, and make a comparison with LTE models. The dependence on metallicity is very weak, but limb darkening is a moderately strong function of log(g) in this temperature regime.