The Nature of the Light Variation of the Unique Binary DK CVn
H. A. Dal A B , E. Sipahi A and O. Özdarcan AA Department of Astronomy and Space Sciences, University of Ege, Bornova, 35100 İzmir, Turkey
B Corresponding author. Email: ali.dal@ege.edu.tr
Publications of the Astronomical Society of Australia 29(1) 54-65 https://doi.org/10.1071/AS11039
Submitted: 2 August 2011 Accepted: 30 November 2011 Published: 22 December 2011
Abstract
We present BVR observations of DK CVn from 2007 and 2008. We analysed the BVR light curves of the system and obtained the system’s parameters. Using the ‘q-search’ method, we measured the mass ratio of the system (q) as 0.55. Taking the temperature of the primary component as 4040 K, the temperature of the secondary was found to be 3123 K. Several flares were detected, and the distributions of flare equivalent duration versus flare total duration were modelled using the One-Phase Exponential Association Function for these flares. The parameters of the model demonstrated that the flares are the same as those detected from UV Ceti stars. We also demonstrate that the variation at out-of-eclipse must be caused by some cool spot(s) on one of the components. The star is found to show two active longitudes in which the spots are mainly formed. Consequently, this study reveals that DK CVn should be a chromospherically active binary star.
Keywords: binaries: close — stars: activity — stars: individual: DK CVn — stars: flare — stars: spots
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