Crescent Nebula

NGC 6888 in Cygnus is a wolf-rayet wind nebula — a shell of gas blown off and energised by the massive, rapidly evolving star WR 136 at its centre. Lying around 5,000 light-years away, the crescent shape is formed where the current fast stellar wind slams into slower material ejected during an earlier red giant phase. WR 136 will almost certainly end its life as a supernova within the next few hundred thousand years.