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Stellar Spectra in the H Band

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Robert F. Wing

Department of Astronomy, Ohio State University, Columbus, OH 43210

Uffe G. Jørgensen

Niels Bohr Institute, and Astronomical Observatory, University of Copenhagen, DK-2100 Copenhagen, Denmark

Presented at the 91st Annual Meeting of the AAVSO, October 26, 2002

[Ed. note: Since this paper was given, the AAVSO has placed 5 near-IR SSP-4 photometers with observers around the world; J and H observations of program stars are being obtained and added to the AAVSO International Database.]

Abstract  The H band is a region of the infrared centered at wavelength 1.65 microns in a clear window between atmospheric absorption bands. Cool stars such as Mira variables are brightest in this band, and the amplitudes of the light curves of Miras are typically 5 times smaller in H than in V. Since the AAVSO is currently exploring the possibility of distributing H-band photometers to interested members, it is of interest to examine the stellar spectra that these photometers would measure. In most red giant stars, the strongest spectral features in the H band are a set of absorption bands due to the CO molecule. Theoretical spectra calculated from model atmospheres are used to illustrate the pronounced flux peak in H which persists over a wide range of temperature. The models also show that the light in the H band emerges from deeper layers of the star’s atmosphere than the light in any other band.

Link to ADS abstract, article and citation information [5]