M50 is about 2,900 light-years away from Earth[2] and is near to but narrowly not estimated to be gravitationally tied to the Canis Major (CMa) OB1 association.[4] It has a core radius of 5.9ly (1.8pc)[7] and spans 17.8ly (5.46pc).[4] The cluster has 508 confirmed and 109 probable members – their combined mass is more than 285M☉, the mean stellar density would thus be 1.3 stars per cubic parsec.[4] It is around 140million years old,[1] with two high-mass white dwarfs[8] and two chemically peculiar stars.[9]
Traditionally considered to be a single star cluster, in 2025 it was found to consist of two separate sub-clusters (NGC 2323-a and NGC 2323-b), making it a binary cluster.[5]
Gallery
Open Messier 50 in Monoceros
Sirius and M41 (lower right), M50 (upper left), and NGC 2360 (lower left)
Messier 50 is found 8° north and 3° east of Sirius
↑Eight out of ninety degrees south of the celestial equator. Thus its light reaches all parts of the Earth, down to a good minimal cumulation 15° above the horizon, on the unobstructed southern horizons of the 67th parallel north. This rules out Iceland and the north coasts of the two northernmost continents.
