Infrared Echelle Spectroscopy of Palomar 6 and M71
Abstract
We present high-resolution infrared echelle spectroscopy for the globular clusters Palomar 6 and M71. Our mean heliocentric radial velocity of Pal 6 is +180.6+/-3.2 km s-1 and is 20 km s-1 lower than that found by Minniti in 1995. Contrary to the previous metallicity estimates using low-resolution spectroscopy, our results show that Pal 6 has an intermediate metallicity, with [Fe/H]=-1.0+/-0.1, and is slightly more metal poor than M71. Reasonable changes in the surface temperature or the microturbulent velocity of the model atmospheres do not affect [Fe/H] at more than +/-0.2 dex. In spite of its high metallicity, on the basis of the spectrum of a single cluster member the [Si/Fe] and [Ti/Fe] ratios of Pal 6 appear to be enhanced by 0.4 and 0.5 dex, respectively, suggesting that the Galactic inner halo may have experienced a very rapid chemical enrichment history.
Based on observations made with the Infrared Telescope Facility, which is operated by the University of Hawaii under contract to the National Aeronautics and Space Administration.- Publication:
-
The Astronomical Journal
- Pub Date:
- November 2004
- DOI:
- 10.1086/425047
- arXiv:
- arXiv:astro-ph/0408269
- Bibcode:
- 2004AJ....128.2388L
- Keywords:
-
- Galaxy: Bulge;
- Galaxy: Globular Clusters: Individual: Name: Palomar 6;
- Galaxy: Globular Clusters: Individual: Messier Number: M71;
- Infrared: Stars;
- Stars: Abundances;
- Astrophysics
- E-Print:
- Accepted for publication in AJ (Nov. 2004)