Do red giants have short mode lifetimes?

Abstract

We show evidence that the red giant star ksi Hya has an oscillation mode lifetime, tau, of about 2 days significantly shorter than predicted by theory (tau = 17 days, Houdek & Gough 2002). If this is a general trend of red giants it would limit the prospects of asteroseismology on these stars because of poor coherence of the oscillations.

4 pages, 6 figures. Meeting on Stellar Pulsation and Evolution, June 2005, Rome. Proceedings to appear in "Memorie della Societa' Astronomica Italiana", Vol 76/4 eds. A.R. Walker & G. Bono