Volume 585, January 2016
|Number of page(s)||27|
|Section||Catalogs and data|
|Published online||18 December 2015|
New atmospheric parameters and spectral interpolator for the MILES cool stars⋆
Université de Lyon, Université Lyon 1,
2 CRAL, Observatoire de Lyon, CNRS UMR 5574, 69561 Saint-Genis Laval, France
3 Department of Physics and Astrophysics, University of Delhi, 110007 Delhi, India
e-mail: email@example.com; firstname.lastname@example.org
Received: 17 March 2015
Accepted: 18 October 2015
Context. The full spectrum fitting of stellar spectra against a library of empirical spectra is a well-established approach to measure the atmospheric parameters of FGK stars with a high internal consistency. Extending it towards cooler stars still remains a challenge.
Aims. We address this question by improving the interpolator of the Medium-resolution INT Library of Empirical Spectra (MILES) library in the low effective temperature regime (Teff < 4800 K), and we refine the determination of the parameters of the cool MILES stars.
Methods. We use the ULySS package to determine the atmospheric parameters (Teff, log g and [Fe/H]), and measure the biases of the results with respect to our updated compilation of parameters calibrated against theoretical spectra. After correcting some systematic effects, we compute a new interpolator that we finally use to redetermine the atmospheric parameters homogeneously and assess the biases.
Results. Based on an updated literature compilation, we determine Teff in a more accurate and unbiased manner compared to those determined with the original interpolator. The validity range is extended downwards to about Teff= 2900 K compared to 3500 K previously. The mean residual biases on Teff, log g, and [Fe/H], with respect to the literature compilation for the coolest stars (Teff ≤ 3800 K) computed using the new interpolator, are −15 K, −0.02 dex, and 0.02 dex respectively. The corresponding estimations of the external precision are 63 K, 0.23 dex, and 0.15 dex respectively. For the stars with Teff in the range 3800−4200 K, the determinations of Teff and [Fe/H] have been slightly improved. At higher temperatures, the new interpolator is comparable to the original one. The new version of the interpolator is publicly available.
Key words: methods: data analysis / techniques: spectroscopic / stars: fundamental parameters
The model as a FITS file is only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (126.96.36.199) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/585/A64
© ESO, 2015
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