Published online by Cambridge University Press: 14 August 2015
In order that a rotating star be in hydrostatic and radiative equilibrium, the effective temperature of the stellar atmosphere must decrease between the star's poles and its equator. Wavelength differences in this “gravity darkening” have been suggested to account for the observed differences in the rotational broadening of lines in the ultraviolet and visual spectral regions (hutchings, 1976; Sonneborn and Collins, 1977). This paper investigates the problem, using detailed model atmospheres to examine the surface brightness distribution of a rapidly rotating star.