A standard stellar library for evolutionary synthesis

A standard library of theoretical stellar spec- tra intended for multiple synthetic photometry appli- cations including spectral evolutionary synthesis is pre- sented. The grid includes M dwarf model spectra, hence complementing the rst library version established in Paper I (Lejeune et al. 1997). It covers wide ranges of fundamental parameters: Te: 50 000 K 2000 K, logg: 5.5 1 :02, and (M=H): +1:0 5 :0. A correction pro- cedure is also applied to the theoretical spectra in or- der to provide color-calibrated flux distributions over a large domain of eective temperatures. For this purpose, empirical Te{color calibrations are constructed between 11500 K and 2000 K, and semi-empirical calibrations for non-solar abundances ((M=H )= 3 :5 to +1.0) are estab- lished. Model colors and bolometric corrections for both the original and the corrected spectra, synthesized in the (UBV)J(RI)CJHKLL 0 M system, are given for the full range of stellar parameters. We nd that the corrected spectra provide a more realistic representation of empiri- cal stellar colors, though the method employed is not com- pletely adapted to the lowest temperature models. In par- ticular the original dierential colors of the grid implied by metallicity and/or luminosity changes are not preserved below 2500 K. Limitations of the correction method used are also discussed.