Astron. Astrophys. 359, 191-212 (2000)

Abundance evolution of intermediate mass elements (C to Zn) in the Milky Way halo and disk

A. Goswami ¹ and N. Prantzos <sup>2

1</sup> Indian Institute of Astrophysics, Bangalore, 560034, India (aruna@iiap.ernet.in)
² Institut d'Astrophysique de Paris, C.N.R.S., 98 bis Bd. Arago, 75014 Paris, France (prantzos@iap.fr)

Received 25 January 2000 / Accepted 16 May 2000

Abstract

We present a comprehensive study of the evolution of the abundances of intermediate mass elements, from C to Zn, in the Milky Way halo and in the local disk. We use a consistent model to describe the evolution of those two galactic subsystems. The halo and the disk are assumed to evolve independently, both starting with gas of primordial composition, and in different ways: strong outflow is assumed to take place during the 1 Gyr of the halo formation, while the disk is built by slowly infalling gas. This description of the halo+disk evolution can correctly account for the main observational constraints (at least in the framework of simple models of galactic chemical evolution). We utilise then metallicity dependent yields to study the evolution of all elements from C and Zn. Comparing our results to an extensive body of observational data (including very recent ones), we are able to make a critical analysis of the successes and shortcomings of current yields of massive stars. Finally, we discuss qualitatively some possible ways to interpret the recent data on oxygen vs iron, which suggest that oxygen behaves differently from the other alpha-elements.

Key words: nuclear reactions, nucleosynthesis, abundances stars: abundances Galaxy: abundances Galaxy: evolution Galaxy: general Galaxy: halo

This article contains no SIMBAD objects.

Contents

• 1. Introduction
• 2. Yields of massive stars and supernova Ia
• 3. The model of galactic chemical evolution
  • 3.1. Stellar lifetimes and remnant masses
  • 3.2. Star formation rate and initial mass function
  • 3.3. Gaseous flows: infall and outflow
• 4. Evolution of the halo and the disk
  • 4.1. Metallicity distribution and O vs. Fe in the halo and the disk
  • 4.2. Evolution of the local disk
• 5. Abundance ratios in the halo and the local disk
  • 5.1. Carbon and Nitrogen
  • 5.2. - elements O, Mg, Si, S, Ca, Ti
  • 5.3. Sodium and Aluminium
  • 5.4. Potassium, Scandium, Vanadium
  • 5.5. Fe-peak elements: Cr, Mn, Co, Ni, Cu and Zn
  • 5.6. Fluorine, Neon, Phosphorous, Chlorine, Argon
  • 5.7. Chemical evolution with respect to Ca
• 6. Alternatives for Oxygen vs. Iron
• 7. Evolution of Mg isotopic ratios
• 8. Summary
• Acknowledgements
• References

© European Southern Observatory (ESO) 2000

Online publication: June 30, 2000
helpdesk.link@springer.de