Abstract
Echelle spectrograms of the flaring red dwarf EV Lac obtained on the Nordic Optical Telescope are used to study the chromosphere of the star during the impulsive flare of 23:19 UT on August 30, 1994, and in two nearby time intervals when UBV RI photometry showed the star to be in a quiescent state. The high spectral resolution of the observations enabled the detection of broad Balmer emission wings in the nonflaring state, which are interpreted as evidence for microflares. Semiempirical models for active regions in the chromosphere, flares, and microflares are constructed and used to compare the main physical characteristics of these structures. The place of the detected microflares in the overall energetics of flare events in EV Lac is discussed.
Similar content being viewed by others
References
R. Kandel, Ann. Astrophys. 30, 999 (1967).
W. L. Kelch, J. L. Linsky, and S. P. Worden, Astrophys. J. 229, 700 (1979).
M. S. Giampapa, S. P. Worden, and J. L. Linsky, Astrophys. J. 258, 740 (1982).
P. J. D. Mauas and A. Falchi, Astron. Astrophys. 281, 129 (1994).
D. Jevremovic, J. G. Doyle, and C. J. Butler, in Proc. 11th Cambridge Workshop on Cool Stars, Stellar Systems, and the Sun, Ed. by R. J. Garcia Lopez, R. Rebolo, and M. R. Zapatero Osorio, Astron. Soc. Pac. Conf. Ser. 223, 815 (2001).
E. A. Baranovskii, R. E. Gershberg, and D. N. Shakhovsko\(\overset{\lower0.5em\hbox{$\smash{\scriptscriptstyle\smile}$}}{l}\), Astron. Zh. 78(1), 78 (2001) [Astron. Rep. 45, 67 (2001)].
E. A. Baranovskii, R. E. Gershberg, and D. N. Shakhovsko\(\overset{\lower0.5em\hbox{$\smash{\scriptscriptstyle\smile}$}}{l}\), Astron. Zh. 78(4), 359 (2001) [Astron. Rep. 45, 309 (2001)].
E. P. Abranin, I. Yu. Alekseev, S. Avgoloupis, et al., Astron. Astrophys. Trans. 17, 221 (1998).
E. A. Baranovskii, E. V. Malanushenko, and A. V. Shumko, Astron. Zh. 74, 454 (1997) [Astron. Rep. 41, 399 (1997)].
V. G. Lozitskii and E. A. Baranovskii, Izv. Krym. Astrofiz. Obs. 88, 67 (1993).
I. Tuominen, I. V. Ilyin, and P. P. Petrov, in Astrophysics with the NOT, Ed. by H. Karttunen and V. Piirola (Univ. of Turku, 1999), p. 47.
I. V. Ilyin, Licentiate dissertation (University of Oulu, 1996).
I. Yu. Alekseev, Astron. Zh. 73, 81 (1996) [Astron. Rep. 40, 69 (1996)].
B. W. Bopp, Mon. Not. R. Astron. Soc. 168, 255 (1974).
P. J. D. Mauas and A. Falchi, Astron. Astrophys. 310, 245 (1996).
C. J. Butler and M. Rodonó, Ir. Astron. J. 17, 131 (1985).
C. J. Butler, M. Rodonó, and B. H. Foing, Astron. Astrophys. 206, L1 (1988).
M. Mathioudakis and J. G. Doyle, Astron. Astrophys. 240, 357 (1990).
J. L. Linsky and B. E. Wood, Astrophys. J. 430, 342 (1994).
B. E. Wood, J. L. Linsky, and T. R. Ayres, Astrophys. J. 478, 745 (1997).
S. H. Saar, M. R. Morgan, J. A. Bookbinder, et al., in Cool Stars, Stellar Systems, and the Sun, Ed. by J.-P. Caillault, Astron. Soc. Pac. Conf. Ser. 64, 471 (1994).
S. H. Saar and J. A. Bookbinder, in Proc. Tenth Cambridge Workshop on Cool Stars, Stellar Systems, and the Sun, Ed. by R. A. Donahue and J. A. Bookbinder, Astron. Soc. Pac. Conf. Ser. 154, 1560 (1998).
R. E. Gershberg and N. I. Shakhovskaya, Astrophys. Space Sci. 95, 235 (1983).
Author information
Authors and Affiliations
Additional information
__________
Translated from Astronomicheski\(\overset{\lower0.5em\hbox{$\smash{\scriptscriptstyle\smile}$}}{l} \) Zhurnal, Vol. 80, No. 4, 2003, pp. 342–356.
Original Russian Text Copyright © 2003 by Alekseev, Baranovski\(\overset{\lower0.5em\hbox{$\smash{\scriptscriptstyle\smile}$}}{l} \), Gershberg, Il’in, Pettersen, Shakhovsko\(\overset{\lower0.5em\hbox{$\smash{\scriptscriptstyle\smile}$}}{l} \), Jablonsky.
Rights and permissions
About this article
Cite this article
Alekseev, I.Y., Baranovskii, É.A., Gershberg, R.E. et al. Modeling of emission spectra of the flaring red dwarf EV Lac: Active regions, flares, and microflares. Astron. Rep. 47, 312–325 (2003). https://doi.org/10.1134/1.1568135
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1134/1.1568135