EDP Sciences Journals List
Advanced Search
Subscriber Authentication Point
Home All issues Volume 400/1 Article
Free access article

Issue A&A
Volume 400, Number 1, March II 2003
Page(s) 21 - 30
Section Galactic structure and dynamics
DOI http://dx.doi.org/10.1051/0004-6361:20021653



A&A 400, 21-30 (2003)
DOI: 10.1051/0004-6361:20021653

The present-day chemical composition of the SMC from UVES spectra of the sharp-lined, B-type dwarf AV 304

W. R. J. Rolleston1, K. Venn2, E. Tolstoy3 and P. L. Dufton1

1  Department of Pure & Applied Physics, The Queen's University of Belfast, BT7 1NN, Northern Ireland, UK
2  University of Minnesota and Macalester College, 1600 Grand Avenue, Saint Paul, MN 55105, USA
3  Kapteyn Institute, University of Groningen, Postbus 800, 9700AV Groningen, The Netherlands

(Received 29 July 2002 / Accepted 12 November 2002 )

Abstract
High-resolution spectroscopic VLT/UVES observations are presented for the B-type main-sequence star, AV 304, in the Small Magellanic Cloud (SMC). These spectra have been analysed using LTE model-atmosphere techniques, to derive stellar atmospheric parameters and chemical compositions. As AV 304 is located within the hydrogen burning main-sequence band, its chemical composition should reflect that of the SMC interstellar medium (ISM). A detailed line-by-line differential analysis has been undertaken relative to a Galactic comparison star. A general metal deficiency for the $\alpha$-process elements O, Si & S of $-0.43\pm0.05$ dex is found for AV 304, with iron having a similar underabundance. Oxygen may be relatively overabundant by ~0.1 dex and carbon and aluminium underabundant by ~0.2 dex. A large nitrogen underabundance (of -1.2 dex relative to hydrogen and -0.7 dex relative to iron) is found. This is interpreted in terms of the CNO bi-cycle having been suppressed in the SMC. Furthermore, the large nitrogen deficiency is in excellent agreement with that found for SMC H II regions. Indeed, this represents a first for stellar astrophysics - confirming the low base-line nitrogen composition of the SMC ISM (viz. 12+log(N/H) ~ 6.66  $\pm$ 0.10 dex).


Key words: stars: abundances -- stars: atmospheres -- stars: early-type -- galaxies: individual: Small Magellanic Cloud

Offprint request: P. L. Dufton, P.Dufton@qub.ac.uk

SIMBAD Objects



© ESO 2003


What is OpenURL?

The OpenURL standard is a protocol for transmission of metadata describing the resource that you wish to access. An OpenURL link contains article metadata and directs it to the OpenURL server of your choice. The OpenURL server can provide access to the resource and also offer complementary services (specific search engine, export of references...). The OpenURL link can be generated by different means.
  • If your librarian has set up your subscription with an OpenURL resolver, OpenURL links appear automatically on the abstract pages.
  • You can define your own OpenURL resolver with your EDPS Account. In this case your choice will be given priority over that of your library.
  • You can use an add-on for your browser (Firefox or I.E.) to display OpenURL links on a page (see http://www.openly.com/openurlref/). You should disable this module if you wish to use the OpenURL server that you or your library have defined.