Metallicity of low-mass stars in Orion
Abstract
Context: Determining the metal content of low-mass members of young associations provides a tool that addresses different issues, such as triggered star formation or the link between the metal-rich nature of planet-host stars and the early phases of planet formation. The Orion complex is a well known example of possible triggered star formation and is known to host a rich variety of proto-planetary disks around its low-mass stars. Available metallicity measurements yield discrepant results.
Aims: We analyzed FLAMES/UVES and Giraffe spectra of low-mass members of three groups/clusters belonging to the Orion association. Our goal is the homogeneous determination of the metallicity of the sample stars, which allows us to look for [Fe/H] differences between the three regions and for the possible presence of metal-rich stars.
Methods: Nine members of the ONC and one star each in the λ Ori cluster and OB1b subgroup were analyzed. After the veiling determination, we retrieved the metallicity by means of equivalent widths and/or spectral synthesis using MOOG.
Results: We obtain an average metallicity for the ONC [{Fe/H}] =-0.01± 0.04. No metal-rich stars were detected and the dispersion within our sample is consistent with measurement uncertainties. The metallicity of the λ Ori member is also solar, while the OB1b star has an [Fe/H] significantly below the ONC average. If confirmed by additional [Fe/H] determinations in the OB1b subgroup, this result would support the triggered star formation and the self-enrichment scenario for the Orion complex.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- July 2009
- DOI:
- 10.1051/0004-6361/200811241
- arXiv:
- arXiv:0905.1840
- Bibcode:
- 2009A&A...501..973D
- Keywords:
-
- stars: pre-main sequence;
- stars: abundances;
- open clusters and;
- associations: individual: Orion;
- stars: planetary systems;
- Astrophysics - Solar and Stellar Astrophysics
- E-Print:
- 13 pages, accepted for publication in A&