Mira

Mira, also known as Omicron Ceti, is the prototype of the long-period Mira-type variable stars. These stars pulsate over extended periods, dramatically changing their brightness over time.

Mira pulsates over a roughly 332-day cycle. During this cycle, its apparent magnitude fluctuates wildly, moving from naked-eye visibility to a level of telescopic faintness that makes it invisible to the unaided eye.

Mira is located approximately 420 light-years away from Earth. Its immense variations in brightness have made it one of the most closely observed stars in astronomical history.

Besides being a pulsating variable, Mira is a dying red giant star that is shedding its outer layers into space. Space telescope observations have revealed that it is traveling through space at a high velocity, creating a tail of shed material similar to a comet.