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Analysis and modeling of high temporal resolution spectroscopic observations of flares on AD Leonis

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Crespo Chacón, I. and Montes Gutiérrez, David and García Álvarez, D. and Fernández Figueroa, María José and López Santiago, J. and Foing, B. H. (2006) Analysis and modeling of high temporal resolution spectroscopic observations of flares on AD Leonis. Astronomy & Astrophysics, 452 (3). pp. 987-1000. ISSN 0004-6361

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Official URL: http://dx.doi.org/10.1051/0004-6361:20053615


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Abstract

We report the results of a high temporal resolution spectroscopic monitoring of the flare star AD Leo. During 4 nights, more than 600 spectra were taken in the optical range using the Isaac Newton Telescope (INT) and the Intermediate Dispersion Spectrograph (IDS). We observed a large number of short and weak flares occurring very frequently (flare activity > 0.71 h^-1). This is consistent with the very important role that flares can play in stellar coronal heating. The detected flares are non white-light flares and, although most solar flares are of this kind, very few such events have been observed previously in stars. The behaviour of different chromospheric lines (Balmer series from H_α to H_11, Ca II H & K, Na I D_1 and D_2, He I 4026 angstrom and He i D_3) was studied in detail for a total of 14 flares. We estimated the physical parameters of the flaring plasma by using a procedure that assumes a simplified slab model of flares. All the obtained physical parameters are consistent with previously derived values for stellar flares, and the areas - less than 2.3% of the stellar surface - are comparable with the size inferred for other solar and stellar flares. We studied the relationships between the physical parameters and the area, duration, maximum flux and energy released during the detected flares.


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© ESO 2006. This work has been supported by the Universidad Complutense de Madrid and the Ministerio de Educación y Ciencia (Spain), under the grants AYA2004-03749 and AYA2005-02750 (Programa Nacional de Astronomía y Astrofísica). Research at Armagh Observatory is grant-aided by the Department of Culture, Arts and Leisure for N. Ireland. I.C.C. acknowledges support from MEC under AP2001-0475. J.L.S. acknowledges support by the Marie Curie Fellowship Contract No. MTKD-CT-2004-002769. We thank the referee for useful comments which have contributed to

Uncontrolled Keywords:Differential emission measure; Extreme-ultraviolet explorer; White-light flares; Late-type stars; X-ray; Rotational modulation; Stellar flares; XMM-Newton; DME stars; UV ceti
Subjects:Sciences > Physics > Astrophysics
Sciences > Physics > Astronomy
ID Code:31463
Deposited On:03 Aug 2015 12:11
Last Modified:10 Dec 2018 15:05

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