The above image is a newly re-processed version from same data set
Taken from DGRO Rancho Hidalgo Animas, New Mexico
14.5" RCOS F8, Apogee U16M High Cooling
Luminance 360, Red 180, Green 140, Blue 180
Calibrated,combined in CCD Stack all other processing done using PS5.
The starburst galaxy NGC 2782 lies about 110 million light years away toward the Lynx constellation. This shows the result when two galaxies of unequal mass collided about 200 million years ago. Their gravitational pull ripped out two tails of debris with very different properties.
The optically bright eastern tail has some neutral hydrogen gas and molecular gas at the base of the tail, and an optically bright, but gas-poor concentration at the end of the tail. The optically faint western tail is rich in neutral hydrogen gas, but has no molecular gas, yet astronomers have recently found blue star clusters younger than 100 million years along both tails, indicating that those stars formed within both tails after the galaxy collision occurred.
Current star-formation theory suggests that star clusters are formed from the collapse of giant molecular gas clouds, but if this were the case, astronomers would expect to see remnants of the molecular gas which helped give birth to the stars in both of the tails of NGC 2782.
Finding unexpected young star clusters in the western tail could help explain why stars form in other places where there is little molecular gas, like the outer edges of the Milky Way galaxy or in the debris of other galaxy collisions.