APOD
Mira: The Wonderful Star
May 5, 2005
About This Image
To seventeenth century astronomers, Omicron Ceti or Mira was known as a wonderful star - a star whose brightness could change dramatically in the course of about 11 months. Modern astronomers now recognize an entire class of long period Mira-type variables as cool, pulsating, red giant stars, 700 or so times the diameter of the Sun. Only 420 light-years away, red giant Mira (Mira A, right) itself co-orbits with a companion star, a small white dwarf (Mira B). Mira B is surrounded by a disk of material drawn from the pulsating giant and in such a double star system, the white dwarf star's hot accretion disk is expected to produce some x-rays. But this sharp, false-color image from the Chandra Observatory also captures the cool giant star strongly flaring at x-ray energies, clearly separated from the x-ray emission of its companion's accretion disk. Placing your cursor over the Chandra x-ray image of Mira will reveal an artist's vision of this still wonderful interacting binary star system.
On This Day in Space History
On May 5, 1961, Alan Shepard became the first American in space on a 15-minute suborbital flight aboard Freedom 7.
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