Long-Duration Solar and Stellar Flares

  • Giannina Poletto
Conference paper


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.


Magnetic Field Strength Solar Phys Solar Flare Reconnection Model Flare Energy 
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  1. Barr, P. and 15 co-authors: 1988, The High-Throughput X-Ray Spectroscopy Mission,ESA SP-1097.Google Scholar
  2. 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 P. A. Sturrock (ed.), Solar Flares, Colo. Assoc. Univ. Press, Boulder,p. 451.Google Scholar
  3. Cargill, P. J. and Priest, E. R.: 1982, Solar Phys. 76, 357.ADSCrossRefGoogle Scholar
  4. Fisher, G. H. and Hawley, S. L.: 1989, in B. M. Haisch and M. Rodonò (eds.), IAU Colloq. 104, Solar and Stellar Flares, Poster Papers, Publ. Catania Astrophys. Obs., Special Volume, p. 353.Google Scholar
  5. 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.ADSCrossRefGoogle Scholar
  6. Hirayama, T.: 1974, Solar Phys. 34, 323.ADSCrossRefGoogle Scholar
  7. Kane, S. R.: 1974, in G. Newkirk, Jr. (ed.), `Coronal Disturbances’, IAU Symp. 57, 105.Google Scholar
  8. Kopp, R. A. and Pneuman, G. W.: 1976, Solar Phys. 50, 85.ADSCrossRefGoogle Scholar
  9. Kopp, R. A. and Poletto, G.: 1984, Solar Phys. 93, 351.ADSCrossRefGoogle Scholar
  10. Lin, R. P.: 1975, in S. R. Kane (ed.), `Solar Gamma-, X- and EUV Radiation’, IAU Symp. 68, 385.Google Scholar
  11. Linsky, J. L.: 1987, Astrophys. Letters Com. 26, 385.Google Scholar
  12. Martin, S. F.: 1979, Solar Phys. 64, 175.ADSGoogle Scholar
  13. Michalitsanos, A. G. and Kupferman, P.: 1974, Solar Phys. 36, 304.CrossRefGoogle Scholar
  14. Moore, R. L. and 15 co-authors: 1980, in P. A. Sturrock (ed.), Solar Flares, Colo. Assoc. Univ. Press, Boulder, p. 341.Google Scholar
  15. Nolte, J. T., Gerassimenko, M., Krieger, A. S., Petrasso, R. D., and Svestka, Z.: 1979, Solar Phys. 62, 123.ADSCrossRefGoogle Scholar
  16. Pallavicini, R., Serio, S., and Vaiana, G. S.: 1977, Astrophys. J. 216, 108.ADSCrossRefGoogle Scholar
  17. Peres, G.: 1989, Solar Phys. 121, 289 (this issue).ADSCrossRefGoogle Scholar
  18. Petrasso, R. D., Nolte, J. T., Gerassimenko, M., Krieger, A. S., Krogstad, R., Seguin, F. H., and Svestka, Z.: 1979, Solar Phys. 62, 133.ADSCrossRefGoogle Scholar
  19. Pneuman, G. W.: 1981, in E. R. Priest (ed.), Solar Flare Magnetohydrodynamics, Gordon and Breach, New York, p. 379.Google Scholar
  20. Pneuman, G. W.: 1982, Solar Phys. 78, 229.ADSCrossRefGoogle Scholar
  21. Poletto, G., Pallavicini, R., and Kopp, R. A.: 1988, Astron. Astrophys. 201, 93.ADSGoogle Scholar
  22. Reale, F., Peres, G., Serio, S., Rosner, R., and Schmitt, J. H. M. M.: 1988, Astrophys. J. 328, 256.ADSCrossRefGoogle Scholar
  23. Saar, S. A. and Linsky, J. L.: 1985, Astrophys. J. 299, L47.ADSCrossRefGoogle Scholar
  24. Svestka, Z.: 1987, in D. Neidig (ed.), The Lower Atmosphere of Solar Flares,NSO/Sac Peak, p. 332.Google Scholar
  25. Svestka, 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.ADSCrossRefGoogle Scholar
  26. Tanaka, K.: 1983, in P. B. Byrne and M. Rodonò (eds.), `Activity in Red Dwarfs’, IAU Colloq. 71, 307.Google Scholar
  27. Van den Oord, G. H. J., and Mewe, R.: 1988, Astron. Astrophys. (in press).Google Scholar
  28. Webb, D. F., Cheng, C.-C., Dulk, G. A., Edberg, S. J., Martin, S. F., McKenna-Lawlor, S., and McLean, D. J.: 1980, in P. A. Sturrock (ed.), Solar Flares, Colo. Assoc. Univ. Press, Boulder, p. 471.Google Scholar

Copyright information

© Kluwer Academic Publishers 1989

Authors and Affiliations

  • Giannina Poletto
    • 1
  1. 1.Osservatorio Astrofisico di ArcetriFirenzeItaly

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