AAS 199th meeting, Washington, DC, January 2002
Session 135. Circumstellar Material and Atmospheres: Hotter
Display, Thursday, January 10, 2002, 9:20am-4:00pm, Exhibit Hall

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[135.10] Possible detections of stellar O~{\small VI} in B-type spectra

J. Zsargo, A. Fullerton (Department of Physics and Astronomy, The Johns Hopkins University), D. Massa (Emergent IT, NASA Goddard Space Flight Center)

One goal of the Far Ultraviolet Spectroscopic Explorer ( FUSE) mission is to study the formation of the O~{\small VI} superion in the stellar winds of Galactic and Magellanic O- and B-type stars. As part of this ongoing effort, we have been analyzing FUSE spectra of a large number of early B-type stars, located both in the Galactic halo and the disk. The objective of this investigation is to determine how far into the domain of the B-type stars stellar O~{\small VI} persists, and correlate its occurrence with other stellar parameters, particularly luminosity.

By comparing the putative wind features in the O~{\small VI} absorption with the N~{\small V}, Si~{\small IV} and C~{\small IV} wind profiles seen in the IUE and STIS spectra, we have definitely identified wind features in the O~{\small VI} absorption of three early B-type giants and supergiants (B0.5II-I, BN1Ib, B1II). Approximately half a dozen others show similar features that we could not yet clearly attribute to the wind. Our preliminary results suggest that the signatures of the wind in O~{\small VI} appear in the spectra of giants and supergiants and not in the main-sequence B-type stars, at or near the terminal velocity of the wind.

This work is based on observations made with the NASA-CNES-CSA Far Ultraviolet Spectroscopic Explorer. FUSE is operated for NASA by the Johns Hopkins University under NASA contract NAS5-32985.

The author(s) of this abstract have provided an email address for comments about the abstract: jzsargo@pha.jhu.edu

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