Mira

Mira is a red giant star in Cetus whose brightness changes dramatically over a cycle of about 11 months. It is the prototype of the long-period variable stars known as Mira variables.

Long-period variable star: A pulsating star whose brightness varies over periods of weeks to years. Mira is the prototype of this class of variable stars.
David Fabricius: A German pastor and astronomer who recorded the first known observation of Mira’s variability in 1596. Fabricius discovered that Mira’s brightness changed over time.
Asymptotic giant branch: A late stellar-evolution phase in which a star develops an inert core and extended shells of nuclear burning. Mira is an evolved star in this phase, approaching substantial envelope loss.
Mira’s light curve: A record of Mira’s measured brightness over time, showing recurring peaks and troughs. Its roughly 11-month cycle is visible in the star’s light curve.
Stellar pulsation: A star’s repeated expansion and contraction caused by oscillations in its interior. Pulsation drives Mira’s recurring changes in radius, temperature, and luminosity.
Johannes Holwarda: A Dutch astronomer who identified Mira’s recurring variability in 1638. Holwarda established that Mira’s changes followed a repeating cycle.
Stellar wind: A continuous outflow of gas from a star into surrounding space. Mira’s wind carries material away from its pulsating atmosphere.
Mira’s ultraviolet tail: A far-ultraviolet feature extending roughly 13 light-years behind Mira, detected by the GALEX space telescope. This observation exposed an enormous trail of material lost by the star.
Mira variable: A pulsating red giant with a large visual brightness range and a period typically longer than 100 days. Mira gives this subgroup of long-period variables its name.
Hevelius: A seventeenth-century Polish astronomer who named the star Mira, meaning “wonderful.” His name captured the striking variability that distinguished Mira.

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