"It's amazing to discover such a startlingly large and important feature of an object that has been known and studied for over 400 years," says James D. GALEX is very sensitive to ultraviolet light and also has an extremely wide field of view, allowing it to scan the sky for unusual ultraviolet activity. The fact that Mira's tail only glows with ultraviolet light might explain why other telescopes have missed it. The process is similar to a speeding boat leaving a choppy wake, or a steam train producing a trail of smoke.
This glowing material then swirls around behind the star, creating a turbulent, tail-like wake. Astronomers think hot gas in the bow shock is heating up the gas blowing off the star, causing it to fluoresce with ultraviolet light. In addition to Mira's tail, GALEX also discovered a bow shock, a type of buildup of hot gas, in front of the star, and two sinuous streams of material coming out of the star's front and back. The pair, also known as Mira A (the red giant) and Mira B (the white dwarf), orbit slowly around each other as they travel together through the constellation Cetus 350 light-years from Earth. Racing along with Mira is a small, distant companion thought to be a white dwarf. It now plows along at 130 kilometers per second, or 291,000 miles per hour. Ĭompared to other red giants, Mira is traveling unusually fast, possibly due to gravitational boosts from other passing stars over time.
Right: Click on the image to play an animated artist's concept of red giant Mira evolving its comet-like tail. The nebula will fade with time, leaving only the burnt-out core of the original star, which will then be called a white dwarf. Mira will eventually eject all of its remaining gas into space, forming a colorful shell called a planetary nebula. Over time, it began to swell into what's called a variable red giant - a pulsating, puffed-up star that periodically grows bright enough to see with the naked eye. "We hope to be able to read Mira's tail like a ticker tape to learn about the star's life."īillions of years ago, Mira was similar to our sun. "This is an utterly new phenomenon to us, and we are still in the process of understanding the physics involved," says co-author Mark Seibert of the Observatories of the Carnegie Institution of Washington in Pasadena. This tail material, visible now for the first time, has been released over the past 30,000 years. As Mira hurtles along, its tail sheds carbon, oxygen and other important elements needed for new stars, planets and possibly even life to form. Mira is an older star called a red giant that is losing massive amounts of surface material. Sign up for EXPRESS SCIENCE NEWS deliveryĪstronomers say Mira's tail offers a unique opportunity to study how stars like our sun die and ultimately seed new solar systems.
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