Asked by: Tallie Blanshard, Honiton
Magnetic fields are created by the motion of electrically conductive material. In some stars, the ionised plasma of their interior undergoes convection. It rises and falls through the outer layers of the star, due to the heating from the stellar core. This, combined with the rotation of the star, creates a ‘dynamo’ that constantly regenerates the star’s magnetic field. The most magnetic stars are those with faster rotation and deeper convection. Other compact and fast-rotating stars, such as pulsars, magnetars and white dwarfs, retain a significant magnetic field from the original star that is increased dramatically when the object collapses under gravity.
Subscribe to BBC Focus magazine for fascinating new Q&As every month and follow @sciencefocusQA on Twitter for your daily dose of fun science facts.
