Abstract
Radio observations provide the most direct information on nonthermal electrons in stellar flares and in the coronae of late-type stars. Radio emissions of single main-sequence F, G, and of many K stars have recently been discovered, in addition to the well-known dwarf M stars. Their long-duration radio flares with low circular polarization, slow variations and broad bandwidth can be attributed to gyrosynchrotron emission of mildly relativistic electrons. The same holds for the low-level (‘quiescent’) radio emission. On the other hand, highly polarized radio flares of M stars have been interpreted by coherent emissions from loss-cone instabilities of magnetically trapped electrons. These conjectures are consistent with recent VLBI observations. The identification of the radio emission process allows to estimate the high-energy component of the flare and compare it to the total flare energy. The weakly polarized radio emission may serve as a proxy for hard X-ray signatures of relativistic electrons. The fraction of primary energy released into energetic electrons then appears to be large and similar to solar flares.
Preview
Unable to display preview. Download preview PDF.
References
Bastian T.S., 1990, Solar Phys. 130, 265
Benz A.O., 1993, Plasma Astrophysics, Kluwer, Dordrecht, Holland
Benz A.O., Alef W., Güdel M., 1995, A&A, in press
Benz A.O., Güdel M., 1994, A&A 285, 621
Drake S.A., Simon T., Linsky J.L., 1989, ApJS 71, 905
Drake S.A., Simon T., Brown A., 1993, ApJ 406, 247
Duijveman A., Hoyng P., Machado M., 1982, Solar Phys. 81, 137
Fox D.C. et al., 1994, A&A 284, 91
Gary D.F., Linsky J.L., 1981, ApJ 250, 284
Gary D.F., Linsky J.L., Dulk G.A., 1982, ApJ 263, L79
Güdel M., 1992, A&A 264, L31
Güdel M., Benz A.O., 1993, ApJ 405, L63
Güdel M., Schmitt J.H.M.M., Bookbinder J.A., Fleming T., 1993, ApJ 415, 236
Güdel M., Schmitt J.H.M.M., Benz A.O., 1994, Science 265, 933
Güdel M., Schmitt J.H.M.M., Benz A.O., 1995a, A&A 293, L49
Güdel M., Schmitt J.H.M.M., Benz A.O., Elias N.M., 1995b, A&A, in press
Kahler S. et al., 1982, ApJ 252, 239
Karpen J. et al., 1977, ApJ 216, 479
Kellermann I.I., Pauliny-Toth I.I.K., 1969, ApJ 155, L71
Kuijpers J., 1989, Solar Phys. 121, 163
Kundu M.R., Pallavicini R., White S.M., Jackson P.D., 1988, A&A 195, 159
Lang K.R., 1994, ApJSS 90, 753
Lang K.R., Bookbinder J., Golub L., Davis M.M., 1983, ApJ 272, L15
Lim J., White S.M., Nelson G.J., Benz A.O., 1994, ApJ 430, 332
Lim J., White S.M., 1995, ApJ, in press
Linsky J.L., Gary D., 1983, ApJ 274, 776
Melrose D.B., 1986, Instabilities in space and laboratory plasmas, Cambridge Univ. Press, Cambridge
Pallavicini R., Willson R.F., Lang K.R., 1985, A&A 149, 95
Petrosian V., McTiernan J.M., Marschhäuser H., 1994, ApJ 434, 747
Readhead A.C., 1994, ApJ 426, 51
Slee O.B. et al., 1986, Proc. ASA 6, 312
Strong K.T. et al., 1984, Solar Phys. 91, 321
Trigilio C., Umana G., Migenes V., 1993, MNRAS 260, 903
Vilmer N., 1994, ApJS 90, 611
Author information
Authors and Affiliations
Editor information
Rights and permissions
Copyright information
© 1995 Springer-Verlag
About this paper
Cite this paper
Benz, A.O. (1995). Radio emission from flares in single late-type stars. In: Greiner, J., Duerbeck, H.W., Gershberg, R.E. (eds) Flares and Flashes. Lecture Notes in Physics, vol 454. Springer, Berlin, Heidelberg. https://doi.org/10.1007/3-540-60057-4_223
Download citation
DOI: https://doi.org/10.1007/3-540-60057-4_223
Published:
Publisher Name: Springer, Berlin, Heidelberg
Print ISBN: 978-3-540-60057-2
Online ISBN: 978-3-540-49420-1
eBook Packages: Springer Book Archive