Velocity Characteristics Of Rotating Sunspots
Abstract
A statistical study is carried out to investigate the detailed relationship between the rotating sunspots and the emergence of magnetic flux tubes. This paper presents the velocity characteristics of 132 sunspots in 95 solar active regions. The rotational characteristics of the sunspots are calculated from successive SOHO/MDI magnetograms by applying the Differential Affine Veloicty Estimator (DAVE) technique (Schuck, Astrophys. J. 646, 1358, 2006). Among 82 sunspots in active regions exhibiting strong flux emergence, 77% are rotating sunspots with rotational angular velocity larger than 0.4 deg/hr. Among 50 sunspots in active regions without well-defined flux emergence, 28% are rotating, and the sunspot rotation tend to be slower, even ceased, compared to those during the emergence. In addition, we investigated 11 rotating sunspot groups in which both polarities show evidence for contemporary rotation. In seven of these cases the two polarities co-rotate while the other four are found to be counter-rotating. Plausible reasons for the observed characteristics of the rotating sunspots are discussed.
- Publication:
-
AAS/Solar Physics Division Abstracts #42
- Pub Date:
- May 2011
- Bibcode:
- 2011SPD....42.1709Z