MODELING THE NEAR-ULTRAVIOLET BAND OF GK STARS. I. LOCAL THERMODYNAMIC EQUILIBRIUM MODELS

Abstract

We present a grid of LTE atmospheric models and synthetic spectra that covers the spectral class range from mid-G to mid-K, and luminosity classes from V to III, that is dense in T{sub eff} sampling ({Delta}T {sub eff} = 62.5 K), for stars of solar metallicity and moderately metal-poor scaled solar abundance ([A/H]=0.0 and -0.5). All models have been computed with two choices of atomic line list: (1) the 'big' line lists of Kurucz that best reproduce the broadband solar blue and near-UV f{sub {lambda}} level, and (2) the 'small' lists of Kurucz and Peytremann that provide the best fit to the high-resolution solar blue and near-UV spectrum. We compare our model spectral energy distributions to a sample of stars carefully selected from the large catalog of uniformly re-calibrated spectrophotometry of Burnashev with the goal of determining how the quality of fit varies with stellar parameters, especially in the historically troublesome blue and near-UV bands. We confirm that our models computed with the 'big' line list recover the derived T {sub eff} values of the PHOENIX NextGen grid, but find that the models computed with the 'small' line list provide greater internal self-consistency among different spectral bands, and closer agreementmore » with the empirical T{sub eff} scale of Ramirez and Melendez, but not to the interferometrically derived T{sub eff} values of Baines et al. We find no evidence that the near-UV band discrepancy between models and observations for Arcturus ({alpha} Boo) reported in two works by Short and Hauschildt is pervasive, and that Arcturus may be peculiar in this regard.« less