Astronomy and Astrophysics, volume 585A, 64-64 (2016/1-1)
New atmospheric parameters and spectral interpolator for the MILES cool stars.
SHARMA K., PRUGNIEL P. and SINGH H.P.
Abstract (from CDS):
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. 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<4800K), and we refine the determination of the parameters of the cool MILES stars. We use the ULySS package to determine the atmospheric parameters (Teff, logg 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. 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=2900K compared to 3500K previously. The mean residual biases on Teff, logg, and [Fe/H], with respect to the literature compilation for the coolest stars (Teff≤3800K) computed using the new interpolator, are -15K, -0.02dex, and 0.02dex respectively. The corresponding estimations of the external precision are 63K, 0.23dex, and 0.15dex respectively. For the stars with Teff in the range 3800-4200K, 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.
methods: data analysis - techniques: spectroscopic - stars: fundamental parameters
VizieR on-line data:
<Available at CDS (J/A+A/585/A64): table1.dat table7.dat table10.dat table11.dat miles_tgm2.fits>
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