S Orionis

S Orionis is a red giant star on the verge of death.

S Orionis pulsates with a period of 420 days. During this cycle, it changes in brightness by a factor of 500%, and changes diameter by 20%. This ranges from 1.9 to 2.3 AUs.

During these pulsations, the star releases a tremendous amount of dust, which form into concentric rings around the star and expand outward at a speed of 10 km/s. During the star's minimum size, there's more dust production and coronial mass ejections, and then the shell expands, releasing the material into space.