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Comparative Pulsation Calculations with OP and OPAL Opacities

Published online by Cambridge University Press:  15 February 2018

S.M. Kanbur  and
N.R. Simon
S.M. Kanbur
Affiliation:
Department of Physics and Astronomy, University of Nebraska-Lincoln, NE 68588-0111
N.R. Simon
Affiliation:
Department of Physics and Astronomy, University of Nebraska-Lincoln, NE 68588-0111

Extract

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The OPAL opacities (Iglesias and Rogers 1991; Iglesias, Rogers and Wilson 1992) are recent revisions to the traditional Los Alamos (LA) opacities and have proven very successful in resolving the Cepheid beat mass, and to a lesser extent, the Cepheid bump mass discrepancies (Moskalik, Buchler and Marom 1991, hereafter MBM). MBM showed that for the beat Cepheids the P1/P0 period ratios, calculated with OPAL, yielded solar masses between 4 and 7, in agreement with other mass determinations. MBM also found that the P2/P0 period ratios were reduced, implying higher bump Cepheid masses, though the conflict with standard evolutionary masses was not completely eliminated. We have made linear nonadiabatic pulsation calculations with another set of recently computed opacities, namely those of the Opacity Project (Seaton 1987, 1992, hereafter OP). Since the two teams have employed different techniques in their calculations, it is of interest to compare pulsation results using the two sets of opacities.

Type
Theoretical Breakthroughs
Information
International Astronomical Union Colloquium , Volume 139: New Perspectives on Stellar Pulsation and Pulsating Variable Stars , 1993 , pp. 240
Copyright
Copyright © Cambridge University Press 1993

References

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