Latest observations conducted with the NASA's Galaxy Evolution Explorer UV space telescope reveal young stars forming in the outer regions of the galaxy, some 100,000 light years away from the galactic nucleus. The galaxy in question is known as M83, a spiral galaxy located about 15 million light-years away, south to the Hydra constellation, with the outer arms orbiting loosely in space, where new stars are being created.

"It is absolutely stunning that we find such an enormous number of young stars up to 140,000 light years away from the center of M83," said Max Planck Institute for Astronomy and lead investigator of the Galaxy Evolution Explorer, Frank Bigiel. M83 is only 40,000 light years in diameter, while the Milky Way is about 100,000 light years across.

Although it is not the first time when astronomers discover stars so far away from the galactic nucleus, the scientists were not expecting to find stars forming in such particular regions of space, knowing the fact that the concentration of matter in these remote areas of the galaxies is especially low. Because the new observations were conducted over a greater period of time, the Galaxy Evolution Explorer was able to reveal that there are more young stars and star clusters in the outer reach of M83 than previously thought to be possible.

Hydrogen, the raw material for stars, appears visible in the electromagnetic spectrum only in the radio wavelengths, thus investigators from the Galaxy Evolution Explorer space telescope had to use the Very Large Array radio observatory to determine the concentration of the gaseous hydrogen atoms in the extremities of the galaxy. By corroborating the UV and radio observations, astronomers realized that the two match precisely.

"The degree to which the ultraviolet emission and therefore the distribution of young stars follows the distribution of atomic hydrogen gas out to the largest distances is absolutely remarkable," said Fabian Walter from the Max Planck Institute for Astronomy, leader of the radio observations. It is likely that the stars in the vicinity of M83 may have formed in a cloud of matter with a low metallicity, like that found in the early universe.

"Even with today's most powerful telescopes, it is extremely difficult to study the first generation of star formation. These new observations provide a unique opportunity to study how early generation stars might have formed," says Mark Seiber of the Observatories of the Carnegie Institution of Washington.