Fekel, Francis C.

Contact Email: fekel@evans.tsuniv.edu
Institute: Center of Excellence in Info Systems,
Tennessee State University, Nashville, TN 37203
First Coauthor: Kenneth H. Hinkle
Institute: NOAO, P.O. Box 26732, Tucson, AZ 85726
Second Coauthor: Thomas Lebzelter
Institute: Institute for Astronomy, University of Vienna, Vienna, Austria
Subject Area: Stellar Atmospheres
Waveband: Infrared
Technique: Spectroscopy
Other: Stellar Variability
Presentation: Poster Display
Title: Velocity Observations of Multiple Mode AGB Variable Stars
Abstract: A sample of nine AGB field M giants with multiple photometric periods has been studied spectroscopically. These stars typically have one period of a few months and another of a few years. For all the stars the short period is typical of pulsation on the AGB. For six of the nine giants our radial- velocity periods confirm the long-period photometric variability. Such periods are significantly longer than the predicted fundamental-mode pulsations for these stars. Nevertheless, we conclude that the long-period velocity changes in most of the giants likely result from pulsation rather than duplicity. The location of these stars in the AGB period-luminosity relation is discussed.