EDP Sciences
Free access
Volume 498, Number 1, April IV 2009
Page(s) 273 - 279
Section Stellar structure and evolution
DOI http://dx.doi.org/10.1051/0004-6361/200911666
Published online 05 March 2009
A&A 498, 273-279 (2009)
DOI: 10.1051/0004-6361/200911666

Deneb's variability: a hint of a deep-lying convection zone?

A. Gautschy

ETH-Zürich, ETH-Bibliothek, Rämistrasse 101, 8092 Zürich, Switzerland
    e-mail: alfred@gautschy.ch

Received 15 January 2009 / Accepted 22 February 2009

During their post – main-sequence evolution, massive star models harbor a convection zone on top of their hydrogen burning shell. This physical property helps, under suitable circumstances, to destabilize low-degree nonradial modes that might explain the cyclic light variability of $\alpha$ Cygni variables. The results of first exploratory computations demonstrate that modes with periods ranging from about one dozen to several dozen days can be overstable in star models at about the position on the HR diagram where the prototype of the class, Deneb, is observed.

Key words: stars: supergiants -- stars: oscillations -- stars: evolution

© ESO 2009