Deneb's variability: a hint of a deep-lying convection zone?A. Gautschy
ETH-Zürich, ETH-Bibliothek, Rämistrasse 101, 8092 Zürich, Switzerland
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 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