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Flares in T Tauri Stars

Published online by Cambridge University Press:  12 April 2016

Gösta F. Gahm
Gösta F. Gahm*
Affiliation:
Stockholm Observatory, S-133 36 Saltsjöbaden, Sweden

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This review concerns rapid variability, on time-scales of a few hours or less, occurring on T Tauri stars (TTS). There are several recent reviews on observed properties of TTS (e.g. Appenzeller & Mundt 1989, Bertout 1989, Gahm 1990a, Kuhi & Cram 1989), some with more emphasis on “flare-like” activity (Feigelson et al. 1991, Gahm 1990b, Montmerle 1991, Montmerle et al. 1993), and the ambition below has been to summarize more recent work. We will also give a compilation of published works on observations of optical variability on these time-scales and a related statistical overview. Some early, very interesting and extensive studies of this kind were made here at the Sonneberg Observatory, where for instance Götz & Wenzel (1967) concluded that the light-curve of RW Aurigae contains several components: quasi-periodic fluctuations over days, ‘waves’ over several hours, rapid outbursts with symmetric light-curves, rapid outbursts with asymmetric (flare-like) light-curves (see also Fürtig & Wenzel 1964) and small fluctuations with very small amplitudes, which they postulated could be due to changes in the emission line fluxes. Modern photometric results of higher sensitivity and time-resolution confirm the existence of these different types of rapid variations in classical TTS (CTTS), having strong emission (lines and continuous, so called veiling) superimposed on the photospheric absorption line spectrum. As described in the subsequent chapters there are new concepts for the interpretation of the short-lived fluctuations. Concerning the long-term quasi-periodic variations we can now usually relate them to the stellar rotational period (bright or dark spots), let be that RW Aur still is an uncertain case. There are other slow changes most likely related to variable circumstellar extinction in circumstellar dust in the line-of-sight to the star. The long-term optical changes were most recently discussed by Herbst et al. (1994).

Type
Flares in T Tauri Stars
Information
International Astronomical Union Colloquium , Volume 151: Flares and Flashes , 1995 , pp. 202 - 211
Copyright
Copyright © Springer-Verlag 1995

References

Abuladze, O., Vardanian, R.A., Kovalenko, V.M., Kumsishvili, Ja., Melikian, N.D., Mironov, A.V., Oshchepkov, V.A., Stepanian, J.A., Totochava, A., Cherepashchuk, A.M., Shanin, G.I., Shpychka, I.V., Shcherbakov, A.G., 1975, Variable Stars 20, 47*Google Scholar
Alcala, J.M., Covino, E., Franchini, M., Krautter, J., Terranegra, L., Wichmann, R., 1993, A&A 272, 225*Google Scholar
Appenzeller, I., Mundt, R., 1989, A&AR 1, 291 Google Scholar
Basri, G., Batalha, C., 1990, ApJ 363, 654 CrossRefGoogle Scholar
Bastian, U., Mundt, R., 1979, A&AS 36, 57*Google Scholar
Bertout, C., 1989, ARA&A 27, 351 Google Scholar
Bertout, C., Basri, G., Bouvier, J., 1988, ApJ 330, 350 Google Scholar
Bieging, J.H., Cohen, M., Schwartz, P.R., 1984, ApJ 282, 699 CrossRefGoogle Scholar
Bouvier, J., Bertout, C., Bouchet, P., 1988, A&AS 75, 1*Google Scholar
Bouvier, J., Cabrit, S., Fernández, M., Martin, E.L., Matthews, J.M., 1993, A&A 272, 176 Google Scholar
Camenzind, M., 1990, in Reviews in Modem Astron. 3, Klare, G. (ed.), p. 234 Google Scholar
Cohen, M., Schwartz, R.D., 1976, MNRAS 174, 137*Google Scholar
Covino, E., Terranegra, L., Franchini, M., Chavarria, -K C., Stallo, R., 1992, A&AS 94, 273*Google Scholar
Edwards, S., Strom, S.E., Hartigan, P., Strom, K.M., Hillenbrand, A., Herbst, W., Attridge, J., Merrill, K.M., Probst, R., Gatley, I., 1993, AJ 106, 372 Google Scholar
Evans, L., 1987, South African Astron. Obs. Circ. No 11, p. 73*Google Scholar
Evans, L., Koen, M.C.J., 1987, South African Astron. Obs Circ. No 11, p. 21*Google Scholar
Feigelson, E.D., Giampapa, M.S., Vrba, F.J., 1991, in The Sun in Time, Sonett, C.P., Giampapa, M.S. Matthews, M.S. (eds.), Univ. of Arizona Press, p. 658 Google Scholar
Feigelson, E.D., Casanova, S., Montmerle, T., Guibert, J., 1993, ApJ 416, 647 CrossRefGoogle Scholar
Feigelson, E.D., Welty, A.D., Imhoff, C.I., Hall, J.C., Etzel, P.B., Phillips, R.B., Lonsdale, C.J., 1994, ApJ 432, 373 Google Scholar
Fürtig, W., Wenzel, W., 1964, Sterne 40, 35 Google Scholar
Gagné, M., Caillault, J.-P., 1995, ApJS, in pressGoogle Scholar
Gahm, G.F., 1990a, in Formation of Stars and Planets and the Evolution of the Solar System, Battrick, B. (ed.), ESA SP-315, p. 43 Google Scholar
Gahm, G.F., 1990b, in Flare Stars in Star Clusters, Associations and the Solar Vicinity, IAU Sym. 137, Mirzoyan, L.V., Pettersen, B.R., Tsvetkov, M.K. (eds.), Kluwer, Dordrecht, p. 193 CrossRefGoogle Scholar
Gahm, G.F., Gullbring, E., Fischerström, C., Lindroos, K.P., Lodén, K., 1993, A&AS 100, 371*Google Scholar
Gahm, G.F., Loden, K., Gullbring, E., Hartstein, D., 1995a, A&A, in pressGoogle Scholar
Gahm, G.F., Petrov, P., Tuominen, I., Gullbring, E., Ilyin, I., 1994b, in Proc. 4th MUSICOS Workshop, Multi-site Continuous Spectroscopy, Beijing June 1994, in pressGoogle Scholar
Gershberg, R.E., Shakhovskaya, N.I., 1983, Ap&SS 95, 235 Google Scholar
Götz, W., Wenzel, W., 1967, Mitteilungen über Veränderliche Sterne 4, 71 Google Scholar
Grinin, V.P., Efimov, Ju.S., Krasnobatsev, V.I., Shakovskaya, N.I., Shcherbakov, A.G., Zaitseva, G.V., Kolotilov, E.A., Shanin, G.I., Kiselev, N.N., Gjulaliev, Ch.G., Salmanov, I.R., 1980, Variable Stars 21, 247*Google Scholar
Guenther, E., Hessman, F.V., 1993, A&A 268, 192 Google Scholar
Gullbring, E., 1994, A&A 287, 131 Google Scholar
Hartigan, P., Kenyon, S.J., Hartmann, L., Strom, S.E., Edwards, S., Welty, A.D., Stauffer, J., 1991, ApJ 382, 617 CrossRefGoogle Scholar
Herbig, G.F., Goodrich, R.W. 1986, ApJ 309, 294*Google Scholar
Herbig, G.H., Bell, K.R., 1988, Lick Obs. Bull., No 1111 Google Scholar
Herbst, W., Holtzman, J.A., Klasky, R.S., 1983 AJ 88, 1648*Google Scholar
Herbst, W., Booth, J.F., Koret, D.L., Zajtseva, G.V., Shakovskaya, N.I., Vrba, F.J., Covino, E., Terranegra, L., Vittone, A., Hoff, D., Kelsey, L., Lines, R., Barksdale, W., 1987 AJ 94, 137*CrossRefGoogle Scholar
Herbst, W., Herbst, D.K., Grossman, E., Weinstein, D., 1994, AJ 108, 1906 Google Scholar
Kardopolov, V.I., Filipev, G.K., 1985, Variable Stars 22, 103*Google Scholar
Kilkenney, D., Whittet, D.C.B., Davies, J.K., Evans, A., Bode, M.F., Robson, E.I., Banfield, R.M., 1985, South African Astron. Obs. Circ. No 9, p. 55*Google Scholar
Kilyachkov, N.N., Shevchenko, V.S., 1976, AZh Lett. 2, 494*Google Scholar
Kolotilov, E.A., 1986, AZh 63, 298*Google Scholar
Königl, A., 1991, ApJ 370, L39 Google Scholar
Koyama, K., Asaoka, I., Kuriyama, T., Tawara, Y., 1992, PASJ 44, L255 Google Scholar
Kuhi, L.V., Cram, L.E., 1989, In: Cram, L.E. & Kuhi, L.V. (eds.) FGK stars and T Tauri stars, NASA SP-502, p. 99 Google Scholar
Lindroos, K.P., 1989, private comm.*Google Scholar
Montmerle, T., 1991, in The Physics of Star Formation and Early Stellar Evolution, NATO ASI Ser. C 392, Lada, C.J. Kylafis, N.D. (eds.), p. 675 Google Scholar
Montmerle, T., André, P., 1988, in Formation and Evolution of Low Mass Stars, NATOASI Ser. C 241, Dupree, A.K., M.T.V.T., (eds.), p. 225 Google Scholar
Montmerle, T., Koch-Miramond, L., Falgarone, E., Grindlay, J.E., 1983, ApJ 269, 182 CrossRefGoogle Scholar
Montmerle, T., Feigelson, E.D., Bouvier, J., André, P., 1993, in Protostars and Planets III, Levy, E.H., Lunine, J.I. (eds.), Univ. of Arizona Press, p. 68 Google Scholar
Mundt, R., 1979, A&A 74, 21*Google Scholar
Neuhäuser, R., Sterzik, M.F., Schmitt, J.H.M.M., Wichmann, R., Krautter, J., 1995, A&A, in pressGoogle Scholar
O’Neal, D., Feigelson, E.D., Mathieu, R.D., Myers, P.C., 1990, AJ 100, 1610 Google Scholar
Pakull, M.W., 1981, A&A 104, 33 Google Scholar
Panagia, N., Felli, M., 1975, A&A 39, 1 Google Scholar
Phillips, R.B., Lonsdale, C.J., Feigelson, E.D., 1991, ApJ 382, 261 Google Scholar
Phillips, R.B., Lonsdale, C.J., Feigelson, E.D., 1993, ApJ 403, L 43 CrossRefGoogle Scholar
Preibisch, Th., Zinnecker, H., Schmitt, J.H.M.M., 1993, A&A 279, L 33 Google Scholar
Pugach, A.F., 1975, Variable StarsS. 2, 195*Google Scholar
Rucinski, S.M., 1983, A&AS 52, 281*Google Scholar
Rucinski, S.M., 1988, Inf. Bull. Variable Stars (IAU), No 3146*Google Scholar
Rucinski, S.M., Krautter, J., 1983, A&A 121, 217*Google Scholar
Rydgren, A.E., Vrba, F.J., 1983, ApJ 267, 191*Google Scholar
Rydgren, A.E., Zak, D.S., Vrba, F.J., Chugainov, P.F., Zaitseva, G.V., 1984, AJ 89, 1015*Google Scholar
Shaimeva, A.F., Shutiomova, N., 1985, Variable Stars 22, 176*Google Scholar
Shevchenko, V.S., Shutiomova, N.A., 1981, Afz 17, 286*Google Scholar
Simon, T., Vrba, F.J., Herbst, W., 1990, AJ 100, 1957*Google Scholar
Skinner, S.L., 1993, ApJ 408, 660 Google Scholar
Stine, P.C., Feigelson, E.D., André, P., Montmerle, T., 1988, AJ 96, 1394 CrossRefGoogle Scholar
Tagliaferri, G., Giommi, P., Angelini, L., Osborne, J.P., Pallavicini, P., 1988, ApJ 331, L 113 Google Scholar
Ushida, Y., Shibata, K., 1984, PASJ 36, 105 Google Scholar
Ushida, Y., Shibata, K., 1985, PASJ 37, 515 Google Scholar
Valenti, J.A., Basri, G., Johns, C.M., 1993, AJ 106, 2024 CrossRefGoogle Scholar
Vrba, F.J., Rydgren, A.E., Chugainov, P.F., Shakhovskaya, N.I., Zak, D.S., 1986, ApJ 306, 199*Google Scholar
Vrba, F.J., Herbst, W., Booth, J.F., 1988, AJ 96, 1032*CrossRefGoogle Scholar
Vrba, F.J., Rydgren, A.E., Chugainov, P.F., Shakovskaya, N.I., Weaver, W.B., 1989, AJ 97, 483*Google Scholar
Vrba, F.J., Chugainov, P.F., Weaver, Wm.B., Stauffer, J.S., 1993, AJ 106, 1608*Google Scholar
White, S.M., Pallavicini, R., Kundu, M.R., 1992, A&A 259, 149 Google Scholar
Zaitseva, G.V., 1978, Afz 14, 17*Google Scholar
Zaitseva, G.V., 1982, Afz 18, 67*Google Scholar
Zaitseva, G.V., 1988, Afz 31, 489*Google Scholar
Zaitseva, G.V., Lyuti, V.M., 1976, Variable Stars 20, 255*Google Scholar
Zaitseva, G.V., Lyuti, V.M., 1976, Variable Stars 20, 266*Google Scholar
Zaitseva, G.V., Kolotilov, E.A., Petrov, P.P., Tarasov, A.E., Shenavrin, V.I., Shcherbakov, A.G., 1985, AZh Lett. 11, 271 Google Scholar