NGC6888, Crescent Nebula
| H alpha image from 20 x 5 min exposures, binned 1:1, SBIG ST10XME/AO8/ Celestron 9.25 f/4.9 |
The Crescent Nebula (NGC6888) appears to have been created by the bright star in its
center. An hypothesis has the Crescent Nebula beginning to form about 250,000 years ago.
At that time, the massive central star had evolved to a Wolf-Rayet star (WR 136), shedding its
outer envelope in a strong stellar wind. This star is thought to eject the equivalent of our Sun's
mass every 10,000 years. This wind impacts surrounding gas left over from a previous phase,
compacting it into a series of complex shells, and lighting it up. The Crescent Nebula lies
about 4,700 light-years away in the constellation of Cygnus. Star WR 136 will probably
undergo a supernova explosion sometime in the next million years.
center. An hypothesis has the Crescent Nebula beginning to form about 250,000 years ago.
At that time, the massive central star had evolved to a Wolf-Rayet star (WR 136), shedding its
outer envelope in a strong stellar wind. This star is thought to eject the equivalent of our Sun's
mass every 10,000 years. This wind impacts surrounding gas left over from a previous phase,
compacting it into a series of complex shells, and lighting it up. The Crescent Nebula lies
about 4,700 light-years away in the constellation of Cygnus. Star WR 136 will probably
undergo a supernova explosion sometime in the next million years.
