Using Cepheids to determine the galactic abundance gradient. II. Towards the galactic center
Abstract
Based on spectra obtained at the Anglo-Australian Observatory, we present a discussion of the metallicity of the galactic disc derived using Cepheids at galactocentric distances of 4-6 kpc. Our new results together with previous gradient determination (Paper I) show that the overall abundance distribution within the galactocentric distances 4-11 kpc cannot be represented by a single gradient value. The distribution is more likely bimodal: it is flatter in the solar neighbourhood with a small gradient, and steepens towards the galactic center. The steepening begins at a distance of about 6.6 kpc. Based on spectra collected at AAO-Australia.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- March 2002
- DOI:
- 10.1051/0004-6361:20020016
- arXiv:
- arXiv:astro-ph/0112513
- Bibcode:
- 2002A&A...384..140A
- Keywords:
-
- STARS: ABUNDANCES;
- STARS: CEPHEIDS;
- GALAXY: ABUNDANCES;
- GALAXY: EVOLUTION;
- Astrophysics
- E-Print:
- 8 pages, 6 postscript figures, LaTeX, uses Astronomy and Astrophysics macro aa.cls, graphicx package, to be published in Astronomy and Astrophysics (2002) also available at http://www.iagusp.usp.br/~maciel/index.html