Mira

Article By:

Henden, Arne A. American Association of Variable Star Observers, Cambridge, Massachusetts.

Mattei, Janet Akyüz American Association of Variable Star Observers, Cambridge, Massachusetts.

Last reviewed:January 2020

DOI:https://doi.org/10.1036/1097-8542.427500

The first star recognized to have a periodic brightness variation. Mira (officially designated Omicron Ceti, in the constellation Cetus, the Whale) was discovered in 1596 by David Fabricius (or Fabricus), a clergyman and an amateur astronomer from Esens in East Friesland (now in Germany), while he was searching for Mercury. He mistook it for a nova because it later faded from view. However, he saw it reappear 14 years later. Not until 1638 was it recognized to be the first known variable star, when Johann Holwarda, from Franeker, also in Friesland (now in the Netherlands), rediscovered it, and in 1639 determined its period to be 11 months. In 1642, Johannes Hevelius of Danzig, who also observed the star, called it Mira, meaning The Wonderful. Mira is the prototype of an entire class of Mira-type pulsating long-period variables. Although it once resembled the Sun, Mira has evolved into a cool red giant star that is at the end of its life. See also: Giant star; Stellar evolution

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