A&A 527, A136 (2011) Astronomy DOI: 10.1051/0004-6361/201015454 & c ESO 2011 Astrophysics The continuous period search method and its application to the young solar analogue HD 116956 J. Lehtinen1, L. Jetsu1, T. Hackman1,2,P.Kajatkari1, and G.W. Henry3 1 Department of Physics, Gustaf Hällströmin katu 2a (PO Box 64), 00014 University of Helsinki, Finland e-mail:
[email protected] 2 Finnish Centre for Astronomy with ESO, University of Turku, Väisäläntie 20, 21500 Piikkiö, Finland 3 Center of Excellence in Information Systems, Tennessee State University, 3500 John A. Merritt Blvd., Box 9501, Nashville, TN 37209, USA Received 22 July 2010 / Accepted 14 December 2010 ABSTRACT Aims. We formulate an improved time series analysis method for the analysis of photometry of active stars. This new continuous period search (CPS) method is applied to 12 years of V band photometry of the young solar analogue HD 116956 (NQ UMa). Methods. The new method is developed from the previous three stage period analysis (TSPA) method. Our improvements are the use of a sliding window in choosing the modelled datasets, a criterion applied to select the best model for each dataset and the computation of the time scale of change of the light curve. We test the performance of CPS with simulated and real data. Results. The CPS has a much improved time resolution which allows us to better investigate fast evolution of stellar light curves. We can also separate between the cases when the data is best described by periodic (i.e. rotational modulation of brightness) and aperiodic (e.g.