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Paper: |
The Evolutionary and Pulsational Characteristics of Alpha Virginis Including Turbulent Diffusive Mixing |
Volume: |
135, A Half Century of Stellar Pulsation Interpretations: a Tribute to Arthur N. Cox |
Page: |
22 |
Authors: |
Pesnell, W. D.; Odell, A. P. |
Abstract: |
The best-observed star (besides the sun) for comparison to stellar evolution and pulsation theory is Alpha Virginis, a double-line spectroscopic and "visual" binary which shows apsidal motion and Beta Cephei-type pulsation. Unfortunately, it is impossible to fit simultaneously all of the observed properties of this star with one model that also exhibits an unstable pulsation mode of the correct period (see Odell and Pesnell, 32nd Liege Colloquium 1995 procedings), even with new opacities computed by the OPAL group of Rogers and Iglesias (Ap. J. Suppl. 79, 507, 1992).Lyubimkov et al. (Astronomicheskii Zhurnal 72, 212, 1995) have observed that the composition of Alpha Vir A differs from Alpha Vir B in that the helium abundance in the atmosphere of the primary star is significantly higher than the secondary, by approximately a factor of two. Denissenkov (A&A 287, 113, 1994) has suggested that this and other abundance anomolies (CN-cycle processed material) can be explained by Turbulent Diffusive Mixing in early B-stars near the main sequence. Thus it is of interest to determine the effects of this helium abundance change on the properties and stability of models of Alpha Virginis. |
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