科研之友
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摘要
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 (114 <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 (Ieff, log q and [Fe/Ell), 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 T-eff in a more accurate and unbiased manner compared to those determined with the original interpolator. The validity range is extended downwards to about T-eff = 2900 K compared to 3500 K previously. The mean residual biases on Ten, log q, and [Fe/H], with respect to the literature compilation for the coolest stars (T-eff,11, <= 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 T-eff in the range 3800-4200 K, the determinations of T-eff 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.
- 出版日期2016-1
