A new theoretical stellar library for stellar populaãtion applications

P. R. T. Coelho1,2*
1Núcleo de Astrofísica Teórica, Universidade Cruzeiro do Sul, R. Galvão Bueno 868, 01506-000, São Paulo, Brasil
2Insituto de Astronomia, Geofísica e Ciências Atmosféricas, Universidade de São Paulo, R. do Matão 1226, 05508-090, São Paulo, Brasil

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Theoretical libraries have been increasingly used to overcome limitations of empirical libraries, e.g. by exploring atmospheric parameter spaces not well represented in empirical libraries. This work presents a new synthetic library which covers 3000 ≤ Teff ≤ 25000 K, -0.5 ≤ log g ≤ 5.5, and 12 chemical mixtures covering 0.0017 ≤ Z ≤ 0.049 at both scaled-solar and α-enhanced compositions. This library complements previous ones by providing: homogeneous computations of opacity distribution functions, models atmospheres, statistical surface fluxes and high spectral resolution spectra; high resolution spectra with continua slopes corrected by the effect of predicted lines, and; two families of -enhanced mixtures for each scaled-solar iron abundance, to allow studies of the -enhancement both at ‘fixed iron’ and ‘fixed Z’ cases. Comparisons to observed spectra were performed and confirm that the synthetic spectra reproduce well the observations, although there are wavelength regions which should be further improved. The atmospheric parameter scale of the model library was compared to one derived from a widely used empirical library, and no systematic deviation between the scales was found. This is particularly reassuring for methods which use synthetic spectra for deriving atmospheric parameters of stars in spectroscopic surveys.

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Keywords :stars: atmosphere – stars: fundamental parameters – astronomical databases: miscellaneous