2011ApJ...728...17D

Amplitudes and phases of the light variation of a pulsating star in various photometric passbands contain information about the geometry of observed modes. Because oscillation spectra of early B-type main-sequence stars do not exhibit regular patterns, these observables are very often the only ones from which mode identification can be derived. Moreover, these data can yield valuable constraints on mean stellar parameters, subphotospheric convection, microphysics, and atmospheres. We study all possible sources of inaccuracy in theoretical values of the photometric observables, i.e., amplitude ratios and phase differences, of early B-type main-sequence pulsators. Here, we discuss the effects of parameters coming from both model atmospheres and linear nonadiabatic theory of stellar pulsation. In particular, we evaluate for the first time the effect of the departure from the local thermodynamic equilibrium (LTE) approximation. To this end, for non-LTE model atmospheres, we compute tables with the passband fluxes, flux derivatives over effective temperature and gravity, as well as the nonlinear limb-darkening coefficients in 12 passbands most often used. We make these tables publicly available at the Wroclaw HELAS Web site.