Terminal Velocities of Wolf-Rayet Star Winds from Low Resolution IUE Spectra

Attracted by the simplicity of the recently published by Prinja (1994) method of determination of terminal wind velocities in hot stars from low resolution IUE spectra we investigate its application to WR stars. With a large sample of low resolution IUE spectra of WR stars we found even simpler, that is linear instead of square, empirical relation between Delta lambda as defined by Prinja (1994) and terminal wind velocity -- v_infty. Using this new empirical relation we present v_infty for a sample of 85 galactic and LMC stars, 19 of them determined for the first time. We almost tripled the number of terminal velocity determinations for LMC WR stars. The comparison with other determinations shows that this simple method is accurate to within 10-20%. We confirm the correlation between terminal velocity and WC subtype. We also show that terminal velocities of WN stars are lower than that of WCE. A comparison between galactic and LMC stars shows that the LMC WN stars have slower winds in most of WN subtypes.