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On the evolutionary status and instability mechanism of the Luminous Blue Variables (LBV)

Published online by Cambridge University Press:  12 April 2016

André Maeder
André Maeder*
Affiliation:
Geneva ObservatoryCH-1290 Sauverny, Switzerland

Abstract

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Various evolutionary sequences leading to LBV are examined. The sequence O-Of-LBV-WR-SN is well supported by the models; some LBV with relatively lower luminosity may turn into OH/IR sources. The overall duration of the LBV phase depends mainly on the average mass loss rate; for < Ṁ > = 10−3M⊙y−1, it lasts about 104 y.

Very massive stars undergo, when they reach log Teff = 3.9, strong departure from hydrostatic equilibrium due to supra-Eddington luminosities at some depth in the outer layers. This results in heavy mass loss, as the growth rate of the instability is very fast. We suggest that the amount of mass ejected in a shell episode is mainly determined by the mass of such a layer that its thermal adjustment timescale is within an order of magnitude of the stellar dynamical timescale. Simulations of B-light curves due to shell ejections by LBV are performed and some sensitive properties are identified.

Type
Section I: Main Papers, General Discussions, and Two Panel Discussions
Information
International Astronomical Union Colloquium , Volume 113: Physics of Luminous Blue Variables , 1989 , pp. 15 - 26
Copyright
Copyright © Kluwer 1989

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