EVANS C.J., LENNON D.J., TRUNDLE C., HEAP S.R. and LINDLER D.J.
Abstract (from CDS):
Ultraviolet spectra from the Space Telescope Imaging Spectrograph (STIS) are used to determine terminal velocities for 11 O and B-type giants and supergiants in the Small Magellanic Cloud (SMC) from the Si IV and C IV resonance lines. Using archival data from observations with the Goddard High-Resolution Spectrograph and the International Ultraviolet Explorer telescope, terminal velocities are obtained for a further five B-type supergiants. We discuss the metallicity dependence of stellar terminal velocities for supergiants, finding no evidence for a significant scaling between Galactic and SMC metallicities for Teff<30,000 K, consistent with the predictions of radiation-driven wind theory. A comparison of the v∞/vescratio between the SMC and Galactic samples, while consistent with the above statement, emphasizes that the uncertainties in the distances to galactic OB-type stars are a serious obstacle to a detailed comparison with theory. For the SMC sample there is considerable scatter in v∞/vescat a given effective temperature, perhaps indicative of uncertainties in stellar masses.