On the wavelength dependence of rotational line broadening

Abstract

Differences in ultraviolet and visual rotational-line broadening have been investigated for rapidly rotating B stars. Preliminary calculations for the 1113-A Si III and 4481-A Mg II lines indicate that half-intensity widths deviate significantly from that expected in the Struve (1929) model. These rotational half-width variations thus provide a sensitive probe with which to test basic assumptions of stellar rotation theory. The model dependence of observed rotation parameters is discussed.