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Paper: A Strong Flare on the K Dwarf LQ Hya
Volume: 154, Cool Stars, Stellar Systems and the Sun: Tenth Cambridge Workshop
Page: 1508
Authors: Montes, D.; Saar, S. H.; Collier Cameron, A.; Unruh, Y. C.
Abstract: We present high resolution optical echelle spectra and IUE SWP observations during a strong flare on 1993 December 22 in the very active, young, rapidly rotating, single K2 dwarf LQ Hya. The temporal evolution of the flare consists of an initial impulsive phase, characterized by strong continuum enhancement, which started between 02:42 UT (quiescent spectrum) and 04:36 UT (first spectrum with a strong increase in the chromospheric lines). The chromospheric lines reached their maximum intensity ~55 min later, by which time the continuum enhancement had sharply decreased. Thereafter, the line emission slowly decreased in a gradual phase that lasted at least until the end of the observation (07:29 UT). IUE data indicate that quiescent C iv flux levels were not recovered after ~4 UT on the following day. We describe the variation of the continuum enhancement, the optical and the UV lines during the flare. In addition to the emission lines that show strong flare enhancement (e.g., Hα and Hβ), we observe He i D3 going into emission. After subtraction of the quiescent spectrum, we also observe excess emission in He i lines at 4921.9, 5015.7, and 6678.1AA, and in other metal lines such as the Na i D1 and D2, the Mg i b triplet and several Fe i and Fe ii lines. We estimate the energy release during the flare, and analyze the broad components and asymmetries seen in some of the emission lines.
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