Journal article
The hydrogen Lyman-alpha emission of Capella
The Astrophysical journal, Vol.402(2), pp.710-720
01/10/1993
DOI: 10.1086/172171
Abstract
We describe the hydrogen Lyα emission of the spectroscopic binary Capella (G8 III + G0 III) recorded at 0.1 Å resolution by the International Ultraviolet Explorer. The overt changes in the composite line shape with orbital phase are controlled by the active G0 III star and permit a dissection of the stellar components despite the obliteration of the central portion of the profile by atomic hydrogen and deuterium absorption along the 12.5 pc sightline. The Lyα line shape of the active G0 III star is surprisingly asymmetric and possibly is variable. Both characteristics suggest a stellar wind of moderate excitation (2 × 104-1 × 105 K), a key component of the coronal evolution scenario of Simon & Drake for the Hertzsprung-gap giants. In a companion paper Linsky et al. use the intrinsic Lyα line shape of Capella to derive the interstellar hydrogen column density and the cosmologically significant D/H ratio based on a comparison with a 0.015 Å resolution profile obtained by the Goddard High Resolution Spectrograph of the Hubble Space Telescope.
Details
- Title: Subtitle
- The hydrogen Lyman-alpha emission of Capella
- Creators
- Thomas R. AyresA. Brown - University of Colorado BoulderK. G. GayleyJeffrey L. Linsky
- Resource Type
- Journal article
- Publication Details
- The Astrophysical journal, Vol.402(2), pp.710-720
- DOI
- 10.1086/172171
- ISSN
- 0004-637X
- eISSN
- 1538-4357
- Language
- English
- Date published
- 01/10/1993
- Academic Unit
- Physics and Astronomy
- Record Identifier
- 9984428679202771
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