Coudé-feed stellar spectral library – atmospheric parameters^⋆

¹ Université de Lyon, Université Lyon 1, 69622 Villeurbanne, France ; CRAL, Observatoire de Lyon, CNRS UMR 5574, 69561 Saint-Genis Laval, France
e-mail: prugniel@obs.univ-lyon1.fr
² National Astronomical Observatories, Chinese Academy of Sciences, 20A Datun Road, Chaoyang District, Beijing 100012, PR China ; Key Laboratory of Optical Astronomy, NAOC, Chinese Academy of Sciences; Graduate University of the Chinese Academy of Sciences, 19A Yuquan Road, Shijingshan District, Beijing 100049, PR China
e-mail: wuyue@lamost.org
³ Department of Physics and Astrophysics, University of Delhi, India
e-mail: hpsingh@physics.du.ac.in
⁴ IUCAA, Post Bag 4, Ganeshkhind, Pune 411007, India
e-mail: rag@iucaa.ernet.in
⁵ Instituto de Astrofísica de Canarias, La Laguna, E-38200 Tenerife, Spain ; Departamento de Astrofísica, Universidad de La Laguna, 38205 La Laguna, Tenerife, Spain
e-mail: koleva@iac.es

Received: 18 May 2010
Accepted: 19 August 2010

Abstract

Context. Empirical libraries of stellar spectra play an important role in different fields. For example, they are used as reference for the automatic determination of atmospheric parameters, or for building synthetic stellar populations to study galaxies. The CFLIB (Coudé-feed library, Indo-US) database is at present one of the most complete libraries, in terms of its coverage of the atmospheric parameters space (T_eff, log g and [Fe/H]) and wavelength coverage 3460–9464 Å at a resolution of  ~1 Å FWHM. Although the atmospheric parameters of most of the stars were determined from detailed analyses of high-resolution spectra, for nearly 300 of the 1273 stars of the library at least one of the three parameters is missing. For the others, the measurements, compiled from the literature, are inhomogeneous.

Aims. In this paper, we re-determine the atmospheric parameters, directly using the CFLIB spectra, and compare them to the previous studies.

Methods. We use the ULySS program to derive the atmospheric parameters, using the ELODIE library as a reference.

Results. Based on comparisons with several previous studies we conclude that our determinations are unbiased. For the 958 F, G, and K type stars the precision on T_eff, log g, and [Fe/H] is respectively 43 K, 0.13 dex and 0.05 dex. For the 53 M stars they are 82 K, 0.22 dex and 0.28 dex. And for the 260 OBA type stars the relative precision on T_eff is 5.1%, and on log g, and [Fe/H] the precision is respectively 0.19 dex and 0.16 dex. These parameters will be used to re-calibrate the CFLIB fluxes and to produce synthetic spectra of stellar populations.