| Issue |
A&A
Volume 526, February 2011
|
|
|---|---|---|
| Article Number | A99 | |
| Number of page(s) | 11 | |
| Section | Stellar atmospheres | |
| DOI | https://doi.org/10.1051/0004-6361/201015646 | |
| Published online | 05 January 2011 | |
Spectroscopic characterization of a sample of metal-poor solar-type stars from the HARPS planet search program⋆
Precise spectroscopic parameters and mass estimation⋆⋆
1
Centro de Astrofísica, Universidade do Porto,
Rua das Estrelas,
4150-762
Porto,
Portugal
e-mail: sousasag@astro.up.pt
2
Instituto de Astrofísica de Canarias, 38200 La Laguna, Tenerife, Spain
3
Geneva Observatory, Geneva University,
51 Ch. des Mailletes,
1290
Sauverny,
Switzerland
4 Departamento de Física e Astronomia, Faculdade de Ciências da
Universidade do Porto, Portugal
5
Departamento de Astrofisica, Universidade de La
Laguna, 38205
La Laguna, Tenerife,
Spain
Received: 26 August 2010
Accepted: 3 November 2010
Stellar metallicity strongly correlates with the presence of planets and their properties. To check for new correlations between stars and the existence of an orbiting planet, we determine precise stellar parameters for a sample of metal-poor solar-type stars. This sample was observed with the HARPS spectrograph and is part of a program to search for new extrasolar planets.
The stellar parameters were determined using an LTE analysis based on equivalent widths (EW) of iron lines and by imposing excitation and ionization equilibrium. The ARES code was used to allow automatic and systematic derivation of the stellar parameters.
Precise stellar parameters and metallicities were obtained for 97 low metal-content stars. We also present the derived masses, luminosities, and new parallaxes estimations based on the derived parameters, and compare our spectroscopic parameters with an infra-red flux method calibration to check the consistency of our method in metal poor stars. Both methods seems to give the same effective temperature scale.
Finally we present a new calibration for the temperature as a function of B − V and [Fe/H]. This was obtained by adding these new metal poor stars in order to increase the range in metallicity for the calibration. The standard deviation of this new calibration is ~50 K.
Key words: stars: fundamental parameters / planetary systems / stars: abundances / stars: statistics
Based on observations collected at the La Silla Parana Observatory, ESO (Chile) with the HARPS spectrograph at the 3.6-m telescope (ESO runs ID 72.C-0488, 082.C-0212, and 085.C-0063).
Tables 1–3 are only available in electronic form at http://www.aanda.org
© ESO, 2011
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.