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Long-Duration Solar and Stellar Flares

Published online by Cambridge University Press:  12 April 2016

Giannina Poletto*
Affiliation:
Osservatorio Astrofisico di Arcetri, Firenze, Italy

Abstract

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According to one of the most popular classifications, solar flares may be assigned either to the category of small short-lived events, or to the category of large, long-duration two-ribbon (2-R) flares. Even if such a broad division oversimplifies the flare phenomenon, our knowledge of the characteristics of stellar flares is so poor, that it is worthwhile to investigate the possibility of adopting this classification scheme for stellar flares as well. In particular we will analyze Einstein observations of a long duration flare on EQ Peg to establish whether it might be considered as a stellar analogy of 2-R solar events. To this end we apply to EQ Peg data a reconnection model, developed originally for solar 2-R flares, and conclude that stellar observations are consistent with model predictions, although additional information is required to identify uniquely the physical parameters of the flare region. Application of the model to integrated observations of a 2-R solar flare, for which high spatial resolution data are also available, shows, however, that future integrated observations may allow us to solve the ambiguities of the model and use it as a diagnostic tool for a better understanding of stellar flares.

Type
Research Article
Copyright
Copyright © Kluwer 1989

References

Barr, P. and 15 co-authors: 1988, The High-Throughput X-Ray Spectroscopy Mission, ESA SP-1097.Google Scholar
Canfield, R. C., Cheng, C.-C., Dere, K. P., Dulk, G. A., Mc Lean, D. J., Robinson, R. D. Jr., Schmahl, E., Jr., and Schoolman, S. A.: 1980, in Sturrock, P. A. (ed.), Solar Flares, Colo. Assoc. Univ. Press, Boulder, p. 451.Google Scholar
Cargill, P. J. and Priest, E. R.: 1982, Solar Phys. 76, 357.CrossRefGoogle Scholar
Fisher, G. H. and Hawley, S. L.: 1989, in Haisch, B. M. and Rodonò, M. (eds.), IAU Colloq. 104, Solar and Stellar Flares, Poster Papers, Pubi. Catania Astrophys. Obs., Special Volume, p. 353.Google Scholar
Haisch, B. M, Linsky, J. L., Bornmann, P. L., Stencel, R. E., Antiochos, S. K., Golub, L., and Vaiana, G. S.: 1983, Astrophys. J. 267, 280.Google Scholar
Hirayama, T.: 1974, Solar Phys. 34, 323.CrossRefGoogle Scholar
Kane, S. R.: 1974, in Newkirk, G., Jr. (ed.), ‘Coronal Disturbances', IAU Symp. 57, 105.Google Scholar
Kopp, R. A. and Pneuman, G. W.: 1976, Solar Phys. 50, 85.CrossRefGoogle Scholar
Kopp, R. A. and Poletto, G.: 1984, Solar Phys. 93, 351.Google Scholar
Lin, R. P.: 1975, in Kane, S. R. (ed.), ‘Solar Gamma-, X- and EUV Radiation', IAU Symp. 68, 385.Google Scholar
Linsky, J. L.: 1987, Astrophys. Letters Com. 26, 385.Google Scholar
Martin, S. F.: 1979, Solar Phys. 64, 175.Google Scholar
Michalitsanos, A. G. and Kupferman, P.: 1974, Solar Phys. 36, 304.Google Scholar
Moore, R. L. and 15 co-authors: 1980, in Sturrock, P. A. (ed.), Solar Flares, Colo. Assoc. Univ. Press, Boulder, p. 341.Google Scholar
Nolte, J. T., Gerassimenko, M., Krieger, A. S., Petrasso, R. D., and Švestka, Z.: 1979, Solar Phys. 62, 123.Google Scholar
Pallavicini, R., Serio, S., and Vaiana, G. S.: 1977, Astrophys. J. 216, 108.Google Scholar
Peres, G.: 1989, Solar Phys. 121, 289 (this issue).Google Scholar
Petrasso, R. D., Nolte, J. T., Gerassimenko, M., Krieger, A. S., Krogstad, R., Seguin, F. H., and Švestka, Z.: 1979, Solar Phys. 62, 133.Google Scholar
Pneuman, G. W.: 1981, in Priest, E. R. (ed.), Solar Flare Magnetohydrodynamics, Gordon and Breach, New York, p. 379.Google Scholar
Pneuman, G. W.: 1982, Solar Phys. 78, 229.Google Scholar
Poletto, G., Pallavicini, R., and Kopp, R. A.: 1988, Astron. Astrophys. 201, 93.Google Scholar
Reale, F., Peres, G., Serio, S., Rosner, R., and Schmitt, J. H. M. M.: 1988, Astrophys. J. 328, 256.Google Scholar
Saar, S. A. and Linsky, J. L.: 1985, Astrophys. J. 299, L47.Google Scholar
Švestka, Z.: 1987, in Neidig, D. (ed.), The Lower Atmosphere of Solar Flares, NSO/Sac Peak, p. 332.Google Scholar
Švestka, Z., Dodson-Prince, H. W., Martin, S. F., Mohler, O. C., Moore, R. L., Nolte, J. T., and Petrasso, R. D.: 1982, Solar Phys. 78, 271.Google Scholar
Tanaka, K.: 1983, in Byrne, P. B. and Rodonò, M. (eds.), ‘Activity in Red Dwarfs', IAU Colloq. 71, 307.Google Scholar
Van den Oord, G. H. J., and Mewe, R.: 1988, Astron. Astrophys. (in press).Google Scholar
Webb, D. F., Cheng, C.-C., Dulk, G. A., Edberg, S. J., Martin, S. F., McKerma-Lawlor, S., and McLean, D. J.: 1980, in Sturrock, P. A. (ed.), Solar Flares, Colo. Assoc. Univ. Press, Boulder, p. 471.Google Scholar