Starspot activity on the RS CVn-type binary II Pegasi during 1999-2001

National Astronomical Observatories/Yunnan Observatory, Joint Laboratory for Optical Astronomy, Chinese Academy of Sciences, Kunming, PR China

Corresponding author: S.-H. Gu, shenggu@public.km.yn.cn

Received: 19 September 2002
Accepted: 6 May 2003

Abstract

By means of Doppler imaging, new high-resolution spectroscopic observations of II Peg, carried out in three observing seasons from 1999 to 2001, were analyzed. The lines FeI6430.844 Å and CaI6439.075 Å were chosen as map lines, and three surface maps of II Peg were obtained. The results demonstrate that the main features of these surface maps are high-latitude active regions around 60° and no polar cap is seen in the maps. The surface patterns of II Peg show large changes, the largest scale active regions appear in July-Aug. 1999 and then they become small and separated in Feb. 2000. The active longitude switches to another hemisphere in Nov.-Dec. 2001 from the one in Feb. 2000. Such spot evolution is not consistent with the activity cycle derived previously.