By CAITLIN LUKACS
There has been a recent discovery about a very well-known star, astronomers announced at a teleconference this summer. NASA’s spacecraft, the Galaxy Evolution Explorer, has found that Mira, a variable star, has a vast turbulent tail that stretches for 13 light years.
According to Mark Seibert, astronomer at the Observatories of the Carnegie Institution of Washington in Pasadena, Calif., Mira is a highly evolved cool red giant star that has been studied for hundreds of years.
Chris Martin, principal investigator of the Galaxy Evolution Explorer, said that the tail was discovered because the Galaxy Evolution Explorer is mapping the sky in the ultraviolet band for the first time.
One of the images that were obtained from this mapping included Mira and showed that the star had “a bit of curious fluff around it,” he said.
Seibert said that the tail was formed because Mira is moving at a very high speed. He said that the speed causes the compression of interstellar mediums, which give off extremely hot gases. These gases then mix with the cool wind coming off of the star and the mixture flows around behind Mira.
The reason why the tail has not been seen before, Seibert said, is that the processes creating the tail occur in the ultraviolet spectrum, which is invisible to human eyes. In order to see Mira’s tail, a space telescope and a very sensitive ultraviolet eye are needed, he said.
Professor Michael Shara, curator at the American Museum of Natural History in New York, said that Mira’s tail is shedding elements such as carbon, nitrogen and oxygen.
“These are materials that are going to help make new solar systems and, who knows, perhaps life in the future,” he said.
Shara also said that Mira is providing us with a “preview of what our own sun is going to be doing about four or five billion years from now.”
When asked if tails such as Mira’s might be a common feature of stars, Seibert said that Mira is a very common type of star and “we suspect that this phenomenon may actually be quite common … however, we’ve never actually seen this phenomena anywhere else.”
Seibert said Mira was first discovered because it appeared to turn on and off about every 332 days. This blinking out is due to the fact that the star physically expands and contracts over the 332 days, he said. The name Mira was chosen, Seibert said, because it stems from the word for wonderful in Latin.