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A Major Optical Flare on the Recently Discovered X-ray Active dMe Star G102-21

Published online by Cambridge University Press:  12 April 2016

I. Pagano ,
R. Ventura ,
M. Rodonò ,
G. Peres  and
G. Micela
I. Pagano
Affiliation:
Osservatorio Astrofisico di Catania and Istituto di Astronomia dell’Università degli Studi, viale A. Doria 6, I-95125 Catania, Italy
R. Ventura
Affiliation:
Osservatorio Astrofisico di Catania and Istituto di Astronomia dell’Università degli Studi, viale A. Doria 6, I-95125 Catania, Italy
M. Rodonò
Affiliation:
Osservatorio Astrofisico di Catania and Istituto di Astronomia dell’Università degli Studi, viale A. Doria 6, I-95125 Catania, Italy
G. Peres
Affiliation:
Istituto e Osservatorio Astronomico di Palermo, Palazzo dei Normanni, I-90134 Palermo, Italy
G. Micela
Affiliation:
Istituto e Osservatorio Astronomico di Palermo, Palazzo dei Normanni, I-90134 Palermo, Italy

Extract

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During UBV photoelectric measurements of G102-21 - a dM3 star recently discovered as a remarkably active X-ray source by Micela et al. (1995) - we have observed the flare shown in Fig. 1 (left panel). The observed flux increase at flare maximum and the energy output (cf. Table 1) make this event one of the largest amplitude and most energetic flares ever detected on UV Cet-type stars.

The ratios EU/EB (=8.9) and EU/EV (=3.9) are more than 7 and 2 times larger, respectively, than the mean values found for typical dMe flares by Lacy et al. (1976). Moreover, assuming the empirical relation between the absolute magnitude MV and the mean energy dissipation during a flare (Gurzadyan 1980), the energy released in the U band exceeds the predicted one by a factor of ∼ 3 · 103. Clearly, we observed a rather peculiar and rare event that does not appear to be a typical flare on red-dwarf stars.

Type
Flares in Late-type Stars: Radio and Optical
Information
International Astronomical Union Colloquium , Volume 151: Flares and Flashes , 1995 , pp. 95 - 96
Copyright
Copyright © Springer-Verlag 1995

References

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