A new image from NASA’s Galaxy Evolution Explorer shows baby stars being spawned in a desolate region of space more than 100,000 light years from the Southern Pinwheel galaxy’s central nursery, providing a unique opportunity to study the formation of early generation stars.
The Southern Pinwheel galaxy, M83, is located 15 million light years away in the constellation Hydra. "It is absolutely stunning that we find such an enormous number of young stars up to 140,000 light-years away from the centre of M83," said Frank Bigiel of the Max Planck Institute for Astronomy in Germany and lead investigator of the new Galaxy Evolution Explorer observations.
Composite image from NASA's Galaxy Evolution Explorer and the National Science Foundation's Very Large Array in New Mexico. The blue and pink pinwheel in the centre is the galaxy's main stellar disc and the stronger red structures are its extended arms. The Galaxy Evolution Explorer is an ultraviolet survey telescope and shows the young stars in blue and green. The Very Large Array observations show radio emission in red, which reveals that the location of hydrogen atoms in the galaxy's lengthy arms matches up with clusters of the baby stars. Image: NASA/JPL-Caltech/VLA/MPIA.
The discovery came as a surprise to the astronomers because the outlying regions of a galaxy are generally assumed to be relatively barren, lacking in the high concentrations of the ingredients needed for stars to form. Some of M83’s youthful stars were first spotted in the galactic wilderness in 2005, and remote stars were also discovered around other galaxies by the Galaxy Evolution Explorer over subsequent years. The latest ultraviolet images were taken over a longer period of time and reveal many more young clusters of stars at the farthest reaches of the galaxy. Using the Very Large Array, the astronomers made follow-up radio observations in an attempt to locate the raw materials of stars, gaseous hydrogen atoms, and found that the data matched that from the Galaxy Evolution Explorer.
"The degree to which the ultraviolet emission and therefore the distribution of young stars follows the distribution of the atomic hydrogen gas out to the largest distances is absolutely remarkable," said Fabian Walter, also of the Max Planck Institute for Astronomy.
The researchers speculate that the young stars of M83 could have formed under similar conditions to those of the early Universe, a time when space was not yet enriched with dust and heavier elements. "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," said co-investigator Mark Seibert of the Observatories of the Carnegie Institution of Washington in Pasadena.