Spraying operation for control of the black-headed budworm, Vancouver Island, British Columbia, 1957

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A standard stellar library for evolutionary synthesis: I. Calibration of theoretical spectra

A comprehensive hybrid library of synthetic stellar spectra based on three original grids of model atmosphere spectra by Kurucz (1995), Fluks et al. (1994), and Bessell et al. (1989, 1991) is presented. The combined library is intended for multiple-purpose synthetic photometry applications and is constructed in order (i) to cover the largest possible ranges in Teff, log g, and [M/H]), (ii) to provide flux spectra with useful resolution on the uniform grid of wavelengths, and (iii) to provide realistic synthetic broad-band colors for the largest possible parameter and wavelength ranges. For each value of the effective temperature and for each wavelength, we calculate the correction function that must be applied to a (theoretical) solar-abundance model flux spectrum which yields synthetic UBVRIJHKL colors matching the (empirical) color-temperature calibrations derived from observations. The calibration algorithm is designed to preserve the original differential grid properties implied by metallicity and/or luminosity changes in the new library. The corresponding color calibration is described in some detail.Comment: 17 pages, Latex, 19 Figures (postscript), accepted for publication in A&A. Also available with figures as ps-file at http://www.astro.unibas.ch/structure/papers.htm

Spraying operation for control of the black-headed budworm, Vancouver Island, British Columbia, 1957

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A standard stellar library for evolutionary synthesis: II. The M dwarf extension

A standard library of theoretical stellar spectra intended for multiple synthetic photometry applications including spectral evolutionary synthesis is presented. The grid includes M dwarf model spectra, hence complementing the first library version established in Paper I (Lejeune, Cuisinier & Buser 1997). It covers wide ranges of fundamental parameters: Teff : 50,000 K to 2000 K, log g : 5.5 to -1.02, and [M/H] : +1.0 to -5.0. A correction procedure is also applied to the theoretical spectra in order to provide color-calibrated flux distributions over a large domain of effective temperatures. For this purpose, empirical Teff-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 established. Model colors and bolometric corrections for both the original and the corrected spectra, synthesized in the UBVRcIcJHKLL'M system, are given for the full range of stellar parameters. We find that the corrected spectra provide a more realistic representation of empirical stellar colors, though the method employed is not completely adapted to the lowest temperature models. In particular the original differential 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.Comment: Accepted for publication in A&A Supplement Series (LaTex); 22 pages, including 8 postscript figures and 10 tables. Also available at http://www.astro.unibas.ch/~lejeune