Washington, Sept 21: Astronomers have found evidence of star formation in a long gas tail extending well outside its parent galaxy.

Scientists say the discovery suggests that such “orphan” stars might be more prevalent than previously thought.

The team led by Ming Sun of Michigan State University, observed the comet like tail in X-ray light with NASA's Chandra X-ray Observatory and in optical light with the Southern Astrophysical Research (SOAR) telescope in Chile.

Sun said the team found the feature extending more 200,000 light years.

"This is one of the longest tails like this we have ever seen, and, it turns out that this is a giant wake of creation, not of destruction,” said Sun, adding that the tail was created as gas was stripped from a galaxy called ESO 137-001, which is now plunging toward the centre of Abell 3627, a giant cluster of galaxies.

He said observations have further shown that the gas in the tail formed millions of stars.

Large amount of gas and dust needed to form stars and it is typically found only within galaxies. As such, astronomers thought it was unlikely that large numbers of stars would form outside a galaxy.

“This isn't the first time that stars have been seen to form between galaxies. But the number of stars forming here is unprecedented,” said team member Megan Donahue, also of MSU.

The scientists say the evidence for star formation in this tail includes 29 regions of ionized hydrogen glowing in optical light, thought to be from newly formed stars.

These regions are all downstream of the galaxy, located in or near the tail. Two Chandra X-ray sources are near these regions, another indication of star formation activity.

The researchers believe the orphan stars formed within the last 10 million years or so.

They further said that the stars in the tail of this fast-moving galaxy, which is some 220 million light years away, would be much more isolated than the vast majority of stars in galaxies.

“By our galactic standards, these are extremely lonely stars. If life was to form out there on a planet a few billion years from now, they would have very dark skies,” said Mark Voit, another team member from MSU.

The study is scheduled for publication in the December 10 issue of The Astrophysical Journal. (With inputs form ANI)