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Line Profile Variations in Be Stars

Published online by Cambridge University Press:  26 May 2016

Douglas R. Gies
Douglas R. Gies*
Affiliation:
Department of Physics and Astronomy Georgia State University, Atlanta, GA 30303, U.S.A.

Abstract

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The periodic variations in the photospheric lines of Be stars could result from rotation or nonradial pulsations (NRP). Here I review the spectroscopic results on ten Be stars which have been targeted in recent multiwavelength campaigns. Most of the stars display variability consistent with an l = –m = 2 NRP mode with periods on the order of a day, and the associated light curves are consistent with the pulsation periods, amplitudes, and phases derived from spectroscopy. The variability is strongest in the line wings which only agrees with the NRP prediction that horizontal motions should exceed vertical motions for g-mode pulsations. High frequency, non-periodic variations are also observed, but I argue that these are of circumstellar origin and do not represent high-order NRP. The NRP periods are also found in variations of the Hβ emission line but these probably result from photospheric and not disk variations. However, the same periods occur in the C IV λ1550 P Cygni line, which strongly suggests that NRP modulates the local stellar wind.

Type
1. Pulsation and Rotation
Information
Symposium - International Astronomical Union , Volume 162: Pulsation, Rotation and Mass Loss in Early-Type Stars , 1994 , pp. 89 - 99
Copyright
Copyright © Kluwer 1994 

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