Astronomy and Astrophysics – Astrophysics
Scientific paper
2003-07-25
Mon.Not.Roy.Astron.Soc.345:1187,2003
Astronomy and Astrophysics
Astrophysics
14 pages, 4 figures
Scientific paper
10.1046/j.1365-2966.2003.07101.x
This paper reports positive detections of surface differential rotation on two rapidly rotating cool stars at several epochs, by using stellar surface features (both cool spots and magnetic regions) as tracers of the large scale latitudinal shear that distorts the convective envelope in this type of stars. We also report definite evidence that this differential rotation is different when estimated from cool spots or magnetic regions, and that it undergoes temporal fluctuations of potentially large amplitude on a time scale of a few years. We consider these results as further evidence that the dynamo processes operating in these stars are distributed throughout the convective zone rather than being confined at its base as in the Sun. By comparing our observations with two very simple models of the differential rotation within the convective zone, we obtain evidence that the internal rotation velocity field of the stars we investigated is not like that of the Sun, and may resemble that we expect for rapid rotators. We speculate that the changes in differential rotation result from the dynamo processes (and from the underlying magnetic cycle) that periodically converts magnetic energy into kinetic energy and vice versa. We emphasise that the technique outlined in this paper corresponds to the first practical method for investigating the large scale rotation velocity field within convective zones of cool active stars, and offers several advantages over asteroseismology for this particular purpose and this specific stellar class.
Collier Cameron Andrew
Donati Jean-Francois
Petit Pacal
No associations
LandOfFree
Temporal fluctuations in the differential rotation of cool active stars does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Temporal fluctuations in the differential rotation of cool active stars, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Temporal fluctuations in the differential rotation of cool active stars will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-444722