13 light year tail

A distant star that hurtles through space at extraordinary speeds has a huge, comet-like tail trailing in its wake, astronomers say.

The appendage, which measures a colossal 13 light years in length, was spotted by Nasa's Galaxy Evolution Explorer (Galex) space telescope.

The researchers said that nothing like it had ever been spotted around a star. They believe the star, known as Mira, will help them to study what happens as stars meet their demise.

Mark Seibert, a co-author of the paper, which was published in the journal Nature, and a scientist at the Carnegie Observatories in Pasadena, said: "This is an utterly new phenomenon to us, and we are still in the process of understanding the physics involved."

Mira (also called Mira A) has captivated astronomers for more than 400 years. It sits about 350 light-years from Earth in a constellation known as Cetus, and is accompanied in orbit by a smaller secondary star, called Mira B, forming a binary system.

Billions of years ago, Mira would have been much like our Sun, but as it now enters its death-throes it has swollen into a type of star known as a red giant. As it races through space at 130km/s (80 miles per second) it sheds vast amounts of material.