This is the Cocoon Nebula in Cygnus. This is the summation of 6 x 10 minute images taken in the Ha band. Known as an Emission Nebula, the hydrogen gas in this area is energized by the central star, which cause it to glow in a vary narrow part of the spectrum centered at 656 nm. This is known as the Hydrogen alpha [or Ha] band. The hydrogen gas in this area was most likely caused by the explosion of a star(s) long ago. The explosion peppered the area with the hydrogen gas and the nearby stars make it glow. Because this nebula is quite old, it is now a place for the formation for new stars. This condition is known as a Stellar Nursery. Several stars have already formed in this cluster. Since the new stars in the cluster are all the same age [also the same color] we can calculate the distance to the Cocoon Nebula very accurately. The distance is 3,900 light years from earth.
Star Explodes...No One Injured
This story is inappropriate and should be flagged for moderation. Please choose from one of the following options: