Terminal velocities of luminous, early-type SMC stars

C. J. Evans; D. J. Lennon; C. Trundle; S. R. Heap; D. J. Lindler

doi:10.1086/383306

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arXiv · astro-ph/0401399

Terminal velocities of luminous, early-type SMC stars

C. J. Evans·D. J. Lennon·C. Trundle·S. R. Heap·D. J. Lindler

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Abstract

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, 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 for supergiant stars. A comparison of the $v_\infty / v_{esc}$ ratio between the SMC and Galactic samples, while consistent with the above statement, emphasizes that the uncertainties in the distances to galactic O-stars are a serious obstacle to a detailed comparison with theory. For the SMC sample there is considerable scatter in this ratio at a given effective temperature, perhaps indicative of uncertainties in stellar masses.

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C. J. Evans, D. J. Lennon, C. Trundle, S. R. Heap, D. J. Lindler. 2004-03-12. Terminal velocities of luminous, early-type SMC stars. https://doi.org/10.1086/383306

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