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Wide-Field Photographic Versus Wide-Field CCD Techniques in the Activity Analysis of dM Stars

Published online by Cambridge University Press:  26 July 2016

G. Szécsényi-Nagy
G. Szécsényi-Nagy*
Affiliation:
Eötvös Loránd University, Department of Astronomy, Budapest, Ludovika tér 2. H - 1083, Hungary

Extract

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The Galaxy is abundant in red dwarf stars. According to statistical analyses, their majority is unstable. Simultaneously, more than 60% of the variable stars known in the solar vicinity (r < 20 pc) are flare stars and taking into account the number of BY Dra stars too the proportion of red dwarfs amongst local variables is superior to three quarters. Their absolute visual magnitudes range from +6 to +17.5 or even more (Szécsényi-Nagy 1986a). During flare events their brightness may reach a maximum corresponding to an enhancement of 1000–10,000 times. The amplitude of a large flare in the U band may be as high as 8–10 magnitudes. The events take place nonperiodically in unpredictable moments; no unquestionable periodicity has been found in the time distribution of stellar flares. However the activity level of various flare stars is considerably different. Some of them show observable flare ups with a mean frequency of 1 per hour whilst others produce only one event per annum. For the scarcity of the phenomenon, traditional photoelectric photometry of individual stars is not an adequate means to a better understanding of flare stars.

Type
Part One: Wide-Field Sky Surveys and Patrols
Information
Symposium - International Astronomical Union , Volume 161: Astronomy from Wide-Field Imaging , 1994 , pp. 61 - 64
Copyright
Copyright © Kluwer 1994 

References

Chen, J.-S., 1993. In ‘IAU Comm. 9 WG on WFI’ Newsletter 4, p. 9.Google Scholar
DALSA INC. Photonics Spectra, Vol. 27, Issue 4, p. 67.Google Scholar
Sekiguchi, M. 1993. In ‘IAU Comm. 9 WG on WFI’ Newsletter 4, p. 9.Google Scholar
Szécsényi-Nagy, G., 1986a. In ‘Star Clusters and Associations’, eds. Balázs, B.A. and Szécsényi-Nagy, G., Budapest, p. 59, and references therein.Google Scholar
Szécsényi-Nagy, G. 1986b. In ‘Star Clusters and Associations’, eds. Balázs, B.A. and Szécsényi-Nagy, G., Budapest, p. 101.Google Scholar
Szécsényi-Nagy, G., 1990a. Astrophysics and Space Science, 170, p. 63.CrossRefGoogle Scholar
Szécsényi-Nagy, G., 1990b. In ‘Star Clusters and Associations’, eds. Balázs, B.A. and Szécsényi-Nagy, G., Budapest 1993, p. 55.Google Scholar
Yanagisawa, K., 1993. In ‘IAU Comm. 9 WG on WFI’ Newsletter 4, p. 9.Google Scholar