POSTER PAPER 9.10
Velocity Observations of Multiple Mode AGB Variable Stars
Francis C. Fekel, Kenneth H. Hinkle, Richard R. Joyce, and Thomas Lebzelter
Institute: Tennessee State University, Center of Excellence in
Information Systems, 330 10th Avenue North, Nashville, TN 37203
Institute: National Optical Astronomy Observatory, P.O.
Box 26732, Tucson, AZ 85726-6732
Institute: Institute for Astronomy, Turkenschanzstrasse 17, A1180
Vienna, Austria
Contact Email: fekel@evans.tsuniv.edu
Abstract:
Numerous infrared spectroscopic observations were obtained of eight
AGB field M giants that have multiple periods of light variability. Each
semiregular variable has light changes with a short period of several
months, which is typical of low-amplitude pulsation for stars on the AGB,
as well as a long period of 1-3 years. For six of the eight giants we found
radial-velocity periods that confirm the long-period light variability.
Those periods are significantly longer than the predicted fundamental-mode
pulsations for these stars. Although we consider the possibility that
the velocity variations result from orbital motion, we conclude that the
long-period velocity changes in most, if not all of our sample stars, likely
result from pulsation rather than duplicity. The location of these stars
in the AGB period-luminosity relation is discussed.
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Manuscript submitted: 2001-Sep-14
"The Future of Cool-Star Astrophysics", 2003, Eds. A. Brown,
G. M. Harper, & T. R. Ayres.
Proceedings of 12th Cambridge Workshop on Cool Stars, Stellar Systems,
& The Sun,
© 2003 University of Colorado.