AAS 197, January 2001
Session 111. Galaxy Morphology and Structure
Display, Thursday, January 11, 2001, 9:30-4:00pm, Exhibit Hall

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[111.06] The Maximum Asymptotic Giant Branch Luminosity of an Old, Metal-rich Stellar Population from NICMOS Observations of M32.

G. Worthey (St. Ambrose University), C. J. Grillmair (SIRTF Science Center, Caltech), T. R. Lauer (NOAO), S. M. Faber (UCO/Lick Observatories)

Hubble Space Telescope near infrared images were obtained of a well-studied field 2 arcmin southeast of the nucleus of local group elliptical galaxy M32 in order to better characterize the bright red giants of this stellar population, the bulk of which is thought to be older than 8 Gyr and to have about half the heavy metal abundance of the sun. Theoretical predictions of the maximum luminosity of low-mass asymptotic giant branch (AGB) stars vary strongly with the assumed mass-loss scheme. The M32 AGB stars ascend one magnitude above the first-ascent giants with a sharp cutoff, except for one star another half-magnitude brighter. This observation can be used to constrain theoretical mass-loss assumptions. This project is supported by STScI/NASA.

The author(s) of this abstract have provided an email address for comments about the abstract: gworthey@sau.edu

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