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Spectral Diagnostics for Early-Type Stars in Support of High-Resolution Satellite ObservationHigh-resolution X-ray spectra have recently been obtained using the Chandra X-ray Satellite Observatory for the two hot supergiant stars zeta Pup and delta Ori. The spectra show the presence of strong K-shell line emission from O, Ne, Mg, Si, and S, as well as strong L-shell line emission from Fe. Initial examination of the spectra indicates that the lines are significantly broader than what would be expected for a stationary plasma, and appear to be consistent with Doppler-broadened emission from hot plasma forming in shock-heated regions embedded in the wind (see Figure 1). Chandra has sufficient spectral resolution to study the velocity structure of isolated X-ray line profiles. Our analysis for zeta Pup has shown blue-shifted and skewed line profiles, providing the most direct evidence that the X-ray source is embedded in the stellar wind. The sensitivity of the He-like fir (forbidden-intercombination-resonance) lines to a strong UV radiation field is used to estimate the radial distances at which lines of O VII, Ne IX, Mg XI, Si XIII, and S XV originate.
Document ID
20010032280
Acquisition Source
Goddard Space Flight Center
Document Type
Other
Authors
MacFarlane, Joseph J. (Prism Computational Sciences Madison, WI United States)
Date Acquired
September 7, 2013
Publication Date
January 1, 2001
Subject Category
Astronomy
Funding Number(s)
CONTRACT_GRANT: NAG5-9461
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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