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Overstability of nonradial pulsations in rotating early type stars

Published online by Cambridge University Press:  26 May 2016

Hideyuki Saio  and
Umin Lee
Hideyuki Saio
Affiliation:
Astronomical Institute, Faculty of Science, Tohoku University, Sendai 980, Japan
Umin Lee
Affiliation:
Department of Physics and Astronomy, University of Rochester, Rochester, NY 14627, USA

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We present the result of nonadiabatic analysis for nonradial pulsations in uniformly rotating main sequence models.

The angular dependence of the amplitude of a nonradial pulsation mode with an azimuthal order m in a rotating star is represented by a sum of terms proportional to spherical harmonics Ylm(θ, ø) with l = |m|, |m| + 2,… (even mode) or l = |m| + 1, |m| + 3,… (odd mode; see e.g. Saio and Lee 1991 for detail). (In this paper we consider only even modes.) This property makes the analysis complex compared with the case without rotation, in which a single Ylm expresses the angular dependence of a given mode. In our numerical analysis the summation is truncated, in which only first two terms are taken into account. Lee and Saio (1987) give the differential equations for nonadiabatic nonradial pulsations in a uniformly rotating star. Treating the angular frequency of rotation as a free parameter, we applied the nonadiabatic analysis to a main-sequence evolutionary model, for which the effect of rotation is neglected.

Type
1. Pulsation and Rotation
Information
Symposium - International Astronomical Union , Volume 162: Pulsation, Rotation and Mass Loss in Early-Type Stars , 1994 , pp. 128 - 129
Copyright
Copyright © Kluwer 1994 

References

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