Evolution of interstellar dust and stardust in the solar neighbourhood^*

¹ Center for Astronomy, Institute for Theoretical Astrophysics, University of Heidelberg, Albert-Überle-Str. 2, 69120 Heidelberg, Germany e-mail: gail@ita.uni-heidelberg.de
² Mineralogical Institute, University of Heidelberg, Im Neuenheimer Feld 236, 69121 Heidelberg, Germany

Received: 4 May 2007
Accepted: 25 September 2007

Abstract

Aims.We studied the evolution of the abundance in interstellar dust species that originate in stellar sources and from condensation in molecular clouds in the local interstellar medium of the Milky Way. We determined from this the input of dust material to the Solar System.

Methods.A one-zone chemical evolution model of the Milky Way for the elemental composition of the disk combined with an evolution model for its interstellar dust component similar to that of Dwek (1998) is developed. The dust model considers dust-mass return from AGB stars as calculated from synthetic AGB models combined with models for dust condensation in stellar outflows. Supernova dust formation is included in a simple parametrised form that is gauged by observed abundances of presolar dust grains with a supernova origin. For dust growth in the ISM, a simple method is developed for coupling this with disk and dust evolution models.

Results.A chemical evolution model of the solar neighbourhood in the Milky Way is calculated, which forms the basis for calculating a model of the evolution of the interstellar dust population at the galactocentric radius of the Milky Way. The model successfully passes all standard tests for the reliability of such models. In particular the abundance evolution of the important dust-forming elements is compared with observational results for the metallicity-dependent evolution of the abundances for G-type stars from the solar neighbourhood. It is found that the new tables of Nomoto et al. (2006) for the heavy element production give much better results for the abundance evolution of these important elements than the widely used tables of Woosley & Weaver (1995). The time evolution for the abundance of the following dust species is followed in the model: silicate, carbon, silicon carbide, and iron dust from AGB stars and from supernovae, as well as silicate, carbon, and iron dust grown in molecular clouds. It is shown that the interstellar dust population is dominated by dust accreted in molecular clouds; stardust only forms a minor fraction. Most of the dust material entering the Solar System at its formation does not show isotopic abundance anomalies of the refractory elements, i.e., inconspicuous isotopic abundances do not point to a Solar System origin for dust grains. The observed abundance ratios of presolar dust grains formed in supernova ejecta and in AGB star outflows requires that, for the ejecta from supernovae, the fraction of refractory elements condensed into dust is 0.15 for carbon dust and is quite small (~10^-4) for other dust species.