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On the Excitation Mechanism for the Nonradial Pulsations in ϵ Persei

Published online by Cambridge University Press:  12 April 2016

Eiji Kambe
Affiliation:
Dept. of Geoscience, Nat’l Defence Acad., Yokosuka, Kanagawa 239-8686, Japan
Hideyuki Saio
Affiliation:
Astron.Inst., School of Sci., Tohoku Univ. Sendai980-8578, Japan
Umin Lee
Affiliation:
Astron.Inst., School of Sci., Tohoku Univ. Sendai980-8578, Japan

Abstract

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We have examined whether the kappa-mechanism at the ”Z” opacity bump can excite overstable nonradial pulsation (NRP) modes such as those responsible for the line-profile variations (lpv) observed for ϵ Persei (Gies et al. 1999).

From the lpv modeling with realistic stellar parameters and the state-of-the-art codes, we confirmed that the observed lpv can generally be explained by the modes with l values suggested by Gies et al. (1999). We have also found that some tesseral modes, which have smaller m than those of sectoral modes, can reproduce the observed lpv well for the periods of 3.51hr/3.84 hr and 4.06hr/4.54 hr. Our linear non-adiabatic nonradial pulsation analysis applied to massive (13M––14M) stars shows that the periods of higher |m| values in the co-rotating frame are too long to be excited by the Z-bump kappa-mechanism while the smaller |m| values give marginal consistency.

Type
3. Periodic Variations
Copyright
Copyright © Astronomical Society of the Pacific 2000

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