1. Hαemission line spectroscopy in NGC 330
- Author
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Immo Appenzeller, G. Conti, Harald Nicklas, W. Gassler, Stefan Keller, H. Schink, Karl Tarantik, Gero Rupprecht, K. H. Mantel, Walter Seifert, Otmar Stahl, W. Hummel, B. Muschielok, and E. Mattaini
- Subjects
Physics ,010308 nuclear & particles physics ,Be star ,Metallicity ,Astronomy ,Astronomy and Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,Herbig Ae/Be star ,01 natural sciences ,Spectral line ,Density wave theory ,Stars ,Space and Planetary Science ,0103 physical sciences ,Astrophysics::Solar and Stellar Astrophysics ,Astrophysics::Earth and Planetary Astrophysics ,Emission spectrum ,010303 astronomy & astrophysics ,Astrophysics::Galaxy Astrophysics ,Open cluster - Abstract
We perform an observational test on global oscillations in Be star circumstellar disks in the metal deficient environment of the SMC. According to the hybrid model of disk oscillations early-type Be stars require an optically thin line force to establish a density wave. The low metallicity in the SMC should therefore diminish or prevent the formation of disk oscillations in early-type Be stars. We present short wavelength range spectra around H α of 48 Be stars in the young open cluster NGC 330 in the SMC. We find that the fraction of early-type Be stars in NGC 330 which host a global disk oscillation does not differ from the known fraction of Galactic field Be stars. This observational result is in contradiction to the theoretical prediction. We discuss several interpretations and propose a further observational test.
- Published
- 2001
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