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Evolution of Mira's Enormous Tail
08.15.07
 
timeline of Mira

This chart illustrates the length (top) and age (bottom) of a long comet-like tail of material trailing behind a speeding star called Mira (pronounced My-rah). Mira is located in the bulb-shaped structure at right, but it is very small compared to the tail and is difficult to distinguish. The large dot in the lower left corner is another star that is closer to us than Mira.

The unique tail, discovered by NASA's Galaxy Evolution Explorer in ultraviolet light, is startlingly long, as indicated at the top half of the chart. It stretches about 13 light-years through space, which means that light would take 13 years to travel from one end to the other. For reference, the nearest star to our sun, Proxima Centauri, is about four light-years away. If you could see Mira's tail in the night sky, it would span four full moons-worth of sky.

The bottom half of the chart demonstrates the age of material in the tail. The tail is made up of gas and dust that has been shed by Mira slowly over the past 30,000 years, with the oldest material being at the end (far left) and the newest material being closer to Mira (right). This material consists of oxygen and carbon and other elements that will ultimately make their way into new stars, planets and possibly even life.

The chart also lists a few historical events that happened at various points of time in the development of Mira's tail. For example, 26,000 years ago, when material near the end of Mira's tail was just being released, Neanderthals had recently died out.

Image credit: NASA/JPL-Caltech

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