The Fe V/Fe VI ionization structure in WNE Wolf-Rayet winds.

Abstract

An analysis of the phase-dependent intensity variations of the Fe IV, V, and VI pseudocontinua in four WNE binary systems having different orbital separations is used to obtain information regarding the ionization and velocity structures of the wind of the WR component. The ratio of Fe VI/Fe V decreases in strength as a function of distance from the WR core, and there is evidence that the wind is still undergoing an acceleration at distances greater than 14 solar radii. Scattering in the Fe V pseudocontinuum is shown to be an important effect.