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FUSE Observations of the Stellar Winds of Two O7 Supergiants in the Magellanic Clouds

A. W. Fullerton·P. A. Crowther·O. De Marco·J. B. Hutchings·L. Bianchi·K. R. Brownsberger·D. L. Massa·D. C. Morton·B. L. Rachford·T. P. Snow·G. Sonneborn·J. Tumlinson·A. J. Willis
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Abstract

We compare the stellar wind features in far-UV spectra of Sk -67 111, an O7 Ib(f) star in the LMC, with Sk 80, an O7 Iaf+ star in the SMC. The most striking differences are that Sk 80 has a substantially lower terminal velocity, much weaker O VI absorption, and stronger S IV emission. We have used line-blanketed, hydrodynamic, non-LTE atmospheric models to explore the origin of these differences. The far-UV spectra require systematically lower stellar temperatures than previous determinations for O7 supergiants derived from plane-parallel, hydrostatic models of photospheric line profiles. At these temperatures, the O VI in Sk -67 111 must be due primarily to shocks in the wind.

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A. W. Fullerton, P. A. Crowther, O. De Marco, J. B. Hutchings, L. Bianchi, K. R. Brownsberger, D. L. Massa, D. C. Morton, B. L. Rachford, T. P. Snow, G. Sonneborn, J. Tumlinson, A. J. Willis. 2000-05-02. FUSE Observations of the Stellar Winds of Two O7 Supergiants in the Magellanic Clouds. https://doi.org/10.1086/312787

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