|Title||Rotation and activity in low-mass stars|
We know from the Sun that stars can generate magnetic fields, which
cause sunspots, high-energy X-rays, UV emission, and a plethora of
other activity phenomena including mass ejections that can reach Earth.
On other stars, and perhaps the young Sun, activity is even believed to
handicap the development of life. The Sun's magnetic field is connected
to its rotation through a gigantic dynamo, of which only little is
understood. Other stars are known to rotate a lot faster than the Sun,
and rapid rotation generates higher magnetic field strengths in stars -
just as we know from our bicycles. Interestingly, stellar magnetic
fields back-react on rotation; rapid rotators are being braked very
efficiently by the field they generate.