Research Note

Periodicity in some light curves of the solar analogue V352 Canis Majoris^⋆

¹ Department of Physics, Gustaf Hällströmin katu 2a (PO Box 64), University of Helsinki, 00014 Helsinki, Finland
e-mail: lauri.jetsu@helsinki.fi
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
⁴ Nordic Optical Telescope, 38700 Santa Cruz de la Palma, Spain

Received: 14 October 2013
Accepted: 24 March 2015

Abstract

Aims. We applied the Continuous Period Search (CPS) method to 14 yr of V-band photometry of the active G6.5 solar analog V352 CMa. Our aim was to show that CPS can successfully model the presence or absence of periodicity in low-amplitude light curves.

Methods. CPS computes values for the mean brightness, photometric period, amplitude and minimum of selected datasets. We also applied the Power Spectrum Method (PSM) to these datasets and compared the performance of this frequently applied method to that of CPS.

Results. We found an apparent 11.7 ± 0.5 yr cycle in the mean brightness. The mean of the individual photometric rotation periods is 7.24 ± 0.22 days. The lower limit for the differential rotation coefficient is |k| > 0.12, assuming that period changes in V352 CMa follow the solar pattern. The Kuiper method detected stable, active longitudes rotating with a period of 7.157 ± 0.002 days, from the epochs of light minimum, but these structures vanished after the year 2009. CPS performed better than the traditional PSM, because the latter assumes a sinusoidal model for the data even when this was not correct.