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Norman R. Simon Papers
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Document Type
Article
Date of this Version
1990
Citation
Bulletin of the American Astronomical Society, Vol. 22 (1990), p.1222
Abstract
We re-examine the double-mode RR Lyrae (RRd) mass determination using both new and previously existing linear pulsation models. The independently written Los Alamos (Cox, et al. 1983. Ap. J. 266, 94) and Aikawa (Aikawa and Simon 1983, Ap. J. 273, 346) pulsation codes both yield "canonical" values for the RRd masses, i.e., 0.55 Mʘ for 0o I clusters, and 0.65 Mʘ for 0o II clusters. These results are essentially independent of reasonable changes in helium abundance, the treatment of convection and the formulation of standard opacities. 'We show that recent contrary results by Petersen (1990. preprint) are almost certainly due' to the use of an adiabatic approximation and inappropriate metallicity. Given this, it is further argued that earlier disorepant results due to Kovacs (1985; Acta Astr. 35. 37) ought not to be given a high weight. Finally, we concur with Petersen's (1990) assertion that the 0o I RRd masses could be increased provided that Population II metal opacities turn out to be very high.
Comments
Copyright 1990 American Astronomical Society. Provided by the NASA Astrophysics Data System