Hostname: page-component-cd9895bd7-dzt6s Total loading time: 0 Render date: 2024-12-13T11:37:18.316Z Has data issue: false hasContentIssue false

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
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

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

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
Copyright
Copyright © Springer-Verlag 1995

References

Cristaldi, S., Rodonò, M., 1970, A&AS 2, 223 Google Scholar
Cristaldi, S., Rodonò, M., 1975, in IAU Symp. 67, 75 Google Scholar
Foing, B.H. et al., 1994, A&A, 292, 543 Google Scholar
Gershberg, R.E. et al., 1991, SvA 35, 269 Google Scholar
Gliese, W., Jahreiss, H., 1991, 3th Catalogue of Nearby Stars, ADC, GSFCGoogle Scholar
Gurzadyan, G.A., 1980, Flare Stars, Pergamon, Oxford Google Scholar
Henry, G.W., Hall, D.S., 1991, ApJ 373, L9 CrossRefGoogle Scholar
Lacy, C.H., Moffett, T.J., Evans, D.S., 1976, ApJS 30, 85 CrossRefGoogle Scholar
Micela, G., Favata, F., Pye, J., Sciortino, S., 1995, A&A, in pressGoogle Scholar
Minikulov, N.Kh., 1987, Izv. Krym. Astrofiz. Obs. 76, 43 Google Scholar
Pagano, I., Ventura, R., Rodono, M., Peres, G., Micela, G., 1995, A&A, submittedGoogle Scholar