Doppler images of II Pegasi for 2004-2010
Abstract
Aims: We study the spot activity of
Methods: The observations were collected with the high-resolution SOFIN spectrograph at the Nordic Optical Telescope. The temperature maps were calculated using a Doppler imaging code based on Tikhonov regularization.
Results: We present 12 new temperature maps that show spots distributed mainly over high and intermediate latitudes. In each image, 1-3 main active regions can be identified. The activity level of the star is clearly lower than during our previous study for the years 1994-2002. In contrast to the previous observations, we detect no clear drift of the active regions with respect to the rotation of the star.
Conclusions: Having shown a systematic longitudinal drift of the spot-generating mechanism during 1994-2002, the star has clearly switched to a low-activity state for 2004-2010, during which the spot locations appear more random over phase space. It could be that the star is near to a minimum of its activity cycle.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- February 2012
- DOI:
- 10.1051/0004-6361/201117603
- arXiv:
- arXiv:1106.6237
- Bibcode:
- 2012A&A...538A.126H
- Keywords:
-
- stars: imaging;
- stars: activity;
- starspots;
- stars: individual: HD 224085;
- Astrophysics - Solar and Stellar Astrophysics
- E-Print:
- Accepted for publication in Astron. and Astrophys., 8 pages, 5 figures