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Optical and H-Alpha Emission from Unresolved Red Dwarf Stars in the Galaxy

Published online by Cambridge University Press:  08 February 2017

G. Szécsényi-Nagy
G. Szécsényi-Nagy*
Affiliation:
Eötvös University of Budapest, Department of Astronomy Kun Béla tér 2 1083 Budapest Hungary

Extract

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Although many of the nearest dim and cool stars (the red dwarfs) were catalogued in the early sixties, the majority of the astronomers did not realize that these objects provide almost nine tenths of all the stars in our Galaxy. In fact 90-95% of the stars in the solar vicinity (r ≤ 25 pc) are main sequence stars, and at least 80% of them are M dwarfs. Outside the main sequence (MS) one can find a few subdwarfs and somewhat more white dwarfs, but the contribution of this latter type is not known precisely. Estimates range between 4% and 8%. The relative frequency of giants and supergiants can not be determined from the census of the local star population because they are not represented in a statistically meaningful number. But investigations of much greater cosmic volumes demonstrate that luminosity classes Ia, Ib, II, III, and IV altogether contribute fewer than 1% of the stellar content of the Galaxy.

Type
II. Galactic Background Starlight from UV to IR: Observations and Models
Information
Symposium - International Astronomical Union , Volume 139: The Galactic and Extragalactic Background Radiation , 1990 , pp. 107 - 109
Copyright
Copyright © Kluwer 1990 

References

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