Theoretical gravity and limb-darkening coefficients for the MOST satellite photometric system^⋆

¹ Instituto de Astrofísica de Andalucía, CSIC, Apartado 3004, 18080 Granada, Spain
e-mail: claret@iaa.es
² Las Cumbres Observatory Global Telescope, 6740 Cortona Drive, suite 102, Goleta CA 93117, USA
³ Department of Physics, Broida Hall, UC Santa Barbara CA, USA
⁴ Department of Physics and Astronomy, University of British Columbia, Vancouver BC V6T1Z1, Canada

Received: 27 January 2014
Accepted: 14 May 2014

Abstract

Aims. We present new calculations of limb and gravity-darkening coefficients to be used as input in many fields of stellar physics such as synthetic light curves of double-lined eclipsing binaries and planetary transits, studies of stellar diameters or line profiles in rotating stars.

Methods. We compute the limb-darkening coefficients specifically for the photometric system of the satellite MOST (Microvariability and Oscillations in STars). All computations were performed by adopting the least-square method, but for completeness we also performed calculations for the linear and bi-parametric approaches by adopting the flux conservation method. The passband gravity-darkening coefficients y(λ) were computed by adopting a more general differential equation, which also takes the effects of convection into account.

Results. We used two stellar atmosphere models: ATLAS (plane-parallel) and PHOENIX (spherical and quasi-spherical). We adopted six laws to describe the specific intensity distribution: linear, quadratic, square root, logarithmic, exponential, and a more general one with four terms. The covered ranges of T_eff, log g, metallicities, and microturbulent velocities are (1500–50 000 K, 0–5.5, −5.0–+1.0, 0–8 km s^-1), respectively.