Collinder 69

Collinder 69 is a very young open star cluster in the constellation Orion, also known as Cr 69 and the Lambda Orionis Cluster. It marks the head of Orion, centred on the star Meissa (Lambda Orionis). It is about 1,300 light-years away, and its core spans just over half a degree. A cluster census found about 170 candidate members. It stands out for its extreme youth: only about 5 million years old (estimates range from 1 to 10 million), with many pre-main-sequence stars and brown dwarfs. A giant molecular ring about 9° across, the Lambda Orionis ring (Sh2-264), surrounds it, and it is probably the remnant of a supernova explosion that blew away the parent gas. The ring contains the dark clouds Barnard 30 and 35, where star formation is still going on. In the Collinder list it has magnitude 2.8, though it is a loose group and the individual stars are faint, so it is best seen in binoculars or a small telescope.