APOD: Mira

Mira, or Omicron Ceti of Cetus the Whale (an autumn constellation), is an 11-month variable star 420 light-years away. Astronomer David Fabricus first discovered Mira as a new type of cool, pulsating, red giant. Mira A can become 100 times brighter than "normal" and is 700 times the diameter of our sun. Mira A siphons off its mass to its orbiting companion white dwarf. The White Dwarf's accretion disk is so hot it produces x-rays. The Chandra Observatory took this cool x-ray image.
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