Mira

Mira (ο Cet / 68 Ceti / HD14386 / HIP10826 / ADS 1778 AP / Omicron Ceti) is a binary star in the constellation Cetus consisting of the red giant, Mira A or just Mira, and a white dwarf, Mira B or VZ Ceti. Mira A is also an oscillat

Mira (ο Cet / 68 Ceti / HD14386 / HIP10826 / ADS 1778 AP / Omicron Ceti) is a binary star in the constellation Cetus consisting of the red giant, Mira A or just Mira, and a white dwarf, Mira B or VZ Ceti. Mira A is also an oscillating variable star and was the first non-supernova variable star discovered, with the possible exception of Algol. Apart from the odd Eta Carinae, Mira is the brightest periodic variable in the sky that is not visible during part of its cycle. Its distance is uncertain; pre-Hipparcos estimates centered around 220 light-years,(1) while Hipparcos data suggests a distance of 417 light-years, albeit with a margin of error of ~14%.

The companion star was resolved by the Hubble Space Telescope in 1995, when it was 70 astronomical units from the primary; results were announced in 1997. The HST ultraviolet images and later X-ray images by the Chandra space telescope show a spiral of gas rising off Mira in the direction of Mira B. The companion's orbital period around Mira is approximately 400 years.