This animation depicts a hot star whose strong magnetic field forms a thick ring of diffuse material around the star. As the star rotates, the ring periodically passes in front of the star, dimming the starlight. Particles traveling from the star along the magnetic field [represented as red lines] crash into particles in the ring, instigating minor explosions and adding more material to the ring.
Animation: Greg Bacon (STScI/AVL);
Source Model: Detlef Groote, University of Hamburg
Publication: July 12, 2001