High-Resolution Spectroscopic Observations of Hipparcos Red Clump Giants: Metallicity and Mass Determinations
Abstract
We obtain high-resolution and high signal-to-noise ratio spectra of 39 red clump giants selected from the Hipparcos Catalogue. We determine their atmospheric parameters, iron abundances, α-element enhancements, and masses. We find that the sample can be divided into a metal-poor group and a metal-rich group. The majority of the stars are metal-rich (Z>0.3 Zsolar) with mass around 2 Msolar, while the metal-poor group has lower surface gravity and lower mass. The variation of α-element abundances with [Fe/H] agrees with that of local G and K disk dwarfs. We also show that the metallicity is weakly correlated with the I-band absolute magnitude and the V-I color, in agreement with Udalski's recent findings. We make the high-resolution spectra available over the internet for interested readers.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- April 2001
- DOI:
- 10.1086/319832
- Bibcode:
- 2001ApJ...551L..85Z
- Keywords:
-
- Stars: Abundances;
- Stars: Distances;
- Stars: Late-Type