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The fraction of O-type supergiants in our galaxy in the LMC and in the SMC: an evidence of the correlation between mass loss rate and chemical abundance

Published online by Cambridge University Press:  12 April 2016

G.F. Bisiacchi
Affiliation:
Istituto di Astronomía, Universidad Nacional Autónoma de México
C. Firmani
Affiliation:
Istituto di Astronomía, Universidad Nacional Autónoma de México

Extract

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The distribution of the spectral types of the WR stars in our galaxy is different at different distances from the galactic center. This distribution is also different in all three galaxies, in our, in the LMC and in the SMC. These results have been interpreted as due to the dependence of the mass loss rate from the original chemical abundace which is known to be different in these objects.

On the other hand it has been proposed by Chiosi et al. (1974) and confirmed by Bisiacchi et al. (1978) that most of the 0 supergiants should be stars in the hydrogen burning phase. These authors also find evidence that the large relative number of supergiants among th 0 and early B type stars must be related to the longer time spent by the evolutionary tracks with mass loss at the low gravity region. Recently, a new empirical formula has been proposed by Chiosi (1980) for the mass loss rate as function of the luminosity and temperature of the stars.

Type
Session V - Mass Loss and Stellar Evolution: Massive Stars
Copyright
Copyright © Reidel 1981

References

Bislacchi, G.F., Carrasco, L., Costero, R., Firmani, C., and Rayo, J.F. 1978, in‘Mass Loss and Evolution of O-Type Stars’, IAU Symp. No. 83, eds. Conti, P.S. and De Loore, C.W.H., 301, Dordrecht, Reidel.Google Scholar
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