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Synthetic Template Spectra

Published online by Cambridge University Press:  30 March 2016

Robert L. Kurucz
Robert L. Kurucz*
Affiliation:
Harvard-Smithsonian Center for Astrophysics 60 Garden Street, Cambridge, MA 02138, U.S.A.

Extract

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I will compute representative spectra for all spectral types for which my model calculations (Kurucz 1992; 1993a; 1994a) are valid. High-resolution zero-rotation fluxes and intensities will be distributed on CD-ROMS together with programs (Kurucz 1993B) for broadening the spectra to arbitrary rotation velocities, macroturbulent velocities, and instrumental profiles, and for transmitting the spectrum through an atmosphere.

Since the line data are still not well determined, I actually have to make two calculations, one with only the lines with good wavelengths to preserve wavelength detail, and one with all lines, including predicted, to preserve the energy distribution for photometric calibration. In the first case the spectrum is usable as a radial velocity, abundance, or classification template. Even though the line list is incomplete, its signal-to-noise can be higher than that of observed spectra for cross-correlating.

The models are plane parallel, LTE, in hydrostatic equilibrium, and have no triatomic opacities. Therefore, M stars and supergiants cannot be computed realisticly. The abundances available now are scaled-solar and alpha-enhanced scaled-solar. Individual abundances can be changed for the spectrum calculation. My new model atmosphere program, ATLAS 12 (Kurucz 1993c), which does not yet work, will allow arbitrary abundances.

I have made test calculations for Arcturus, the sun, Vega, Sirius, and a17000K B. star. Figure 1 shows the effect of resolution on the appearance of the spectrum. Figure 2 shows the effect of rotation. The spectrum for Arcturus is displayed in Kurucz (1994b) with the molecular bands labelled.

Type
II. Joint Discussions
Information
Highlights of Astronomy , Volume 10: Highlights of Astronomy. As presented at the XXIInd General Assembly of the IAU, 1994 , 1995 , pp. 407 - 410
Copyright
Copyright © Kluwer 1995

References

Kurucz, R.L. (1992) Model atmospheres for populationsynthesis. in Stellar Population of Galaxies, eds. Baibuy, B. and Renzini, A., Kluwer, Dordrecht, pp. 225–232.Google Scholar
Kurucs, R.L. (1993a) ATLAS9 Stellar Atmosphere Programs and 2 km/s grid, Kuiucz CD-ROM No.13.Google Scholar
Kurucz, R.L. (1993b) SYNTHE Spectrum Synthesis Programs and Line Data, Kurucz CD-ROM No.18.Google Scholar
Kurucz, R.L. (1993c) A new opacity-sampling model atmosphere program for arbitrary abundances, in Peculiar venus Normal Phenomena in A-type and Related Stars, eds. Dworetsky, M.M., Castelli, F., and Faraggiana, R., A.S.P. Conference Series vol. 44, San Francisco, Astronomical Society of the Pacific, pp. 87–97.Google Scholar
Kurucz, R.L. (1994a) Solar abundance model atmospheres for 0, 1,2,4,8 km/s, Kurucz CD-ROM No. 19.Google Scholar
Kurucz, R.L. (1994b) Computation of opacities for diatomic molecules, in IAU Colloquium 146: Molecules in the Stellar Environment, ed. Jorgensen, U.G.. Springer-Verlag, Berlin, pp. 282–295.Google Scholar