Paper: astro-ph/0601130
Date: Fri, 6 Jan 2006 17:22:42 GMT (321kb)

Title: The origin and chemical evolution of carbon in the Galactic thin and
thick disks

Authors: T. Bensby (1), S. Feltzing (2) ((1) Dept. of Astronomy, University of
Michigan, Ann Arbor, USA, (2) Lund Observatory, Sweden)

Comments: 15 pages, accepted for publication in MNRAS
\\
[ABRIDGED] In order to trace the origin and evolution of carbon in the
Galactic disk we have determined carbon abundances in 51 nearby F and G dwarf
stars. The sample is divided into two kinematically distinct subsamples with 35
and 16 stars that are representative of the Galactic thin and thick disks,
respectively. The analysis is based on spectral synthesis of the forbidden [C
I] line at 872.7 nm using spectra of very high resolution (R~220000)and high
signal-to-noise (S/N>300) that were obtained with the CES spectrograph on the
ESO 3.6-m telescope on La Silla in Chile. We find that [C/Fe] versus [Fe/H]
trends for the thin and thick disks are totally merged and flat for sub-solar
metallicities. The thin disk that extends to higher metallicities than the
thick disk,shows a shallow decline in [C/Fe] from [Fe/H]=0 and up to
[Fe/H]=+0.4. The [C/O] versus [O/H] trends are well separated between the two
disks (due to differences in the oxygen abundances)and bear a great resemblance
to the [Fe/O] versus [O/H] trends. Our interpretation of our abundance trends
is that the sources that are responsible for the carbon enrichment in the
Galactic thin and thick disks have operated on a time-scale very similar to
those that are responsible for the Fe and Y enrichment (i.e., SNIa and AGB
stars, respectively)...... For the Galaxy we hence conclude that the carbon
enrichment at metallicities typical of the disk is mainly due to low and
intermediate mass stars, while massive stars are still the main carbon
contributor at low metallicities (halo and metal-poor thick disk).

\\ ( http://arXiv.org/abs/astro-ph/0601130 , 321kb)