Title of article :
Starspot activity on the RS CVn-type binary II Pegasi during 1999-2001
Author/Authors :
Gu، S.-H. نويسنده , , Tan، H.-S. نويسنده , , Wang، X.-B. نويسنده , , Shan، H.-G. نويسنده ,
Issue Information :
روزنامه با شماره پیاپی سال 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 A and CaI6439.075 A 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.
Keywords :
imaging , II Peg , starspots , stars , late-type , Individual , activity
Journal title :
Astronomy and Astrophysics
Journal title :
Astronomy and Astrophysics