High-Resolution Spectroscopic Observations of [ITAL]Hipparcos[/ITAL] Red Clump Giants: Metallicity and Mass Determinations
2001; IOP Publishing; Volume: 551; Issue: 1 Linguagem: Inglês
10.1086/319832
ISSN1538-4357
AutoresGong‐Bo Zhao, Han Qiu, Shude Mao,
Tópico(s)Astronomy and Astrophysical Research
ResumoWe 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 Z☉) with mass around 2 M☉, 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.
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