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Spot activity of II Peg
Author(s) -
Hackman T.,
Mantere M.J.,
Jetsu L.,
Ilyin I.,
Kajatkari P.,
Kochukhov O.,
Lehtinen J.,
Lindborg M.,
Piskunov N.,
Tuominen I.
Publication year - 2011
Publication title -
astronomische nachrichten
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.394
H-Index - 63
eISSN - 1521-3994
pISSN - 0004-6337
DOI - 10.1002/asna.201111616
Subject(s) - photometry (optics) , starspot , dynamo , physics , light curve , doppler effect , hot spot (computer programming) , maxima and minima , astrophysics , peg ratio , doppler imaging , spectroscopy , astronomy , magnetic field , stars , biology , mathematics , mathematical analysis , finance , quantum mechanics , computer science , blood pressure , diastole , economics , endocrinology , operating system
Abstract We have studied the long‐term spot activity of the RS CVn star II Peg by means of Doppler imaging based on spectroscopy and time series analysis of photometry. We present 28 Doppler imaging temperature maps spanning the years 1994–2010, of which 14 were calculated for the present study. The longitudinal spot distribution, derived from the surface temperature maps, is compared with epochs of the light curve minima, derived from photometric observations. We detect a longitudinal drift in the major spot structure during 1995–2003. After this there is a clear decrease in the activity level and no clear drift can be seen. We conclude that the variations could be caused by a cyclic behaviour of the underlying magnetic dynamo (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)