The remarkavle kinematics of the WR wind-blown bubble RCW 58.

Abstract

High resolution, high signal-to-noise ratio, ultraviolet, and optical observations of HD 96548, a WN8 star surrounded by the nebula RCW 58 which consists of stellar ejecta enclosed in a wind-blown bubble, are presented. The spectra exhibit blueshifted absorption components in a number of interstellar lines arising from a variety of ions. The velocities of the components are well correlated with their ionization potentials in the sense that C IV has the highest velocity relative to the star and Fe II the lowest. The likely origin of such a correlation is discussed, and it is argued that the absorption components arise behind the inwards-facing shock within the wind-blown bubble. Significant modifications to the standard bubble model are, however, required by these results; in particular the slope of the velocity/ionization potential relationship is too high for a simple postshock flow.