Messier 50

Messier 50 or M 50, also known as NGC 2323 or the Heart-shaped Cluster, is an open cluster of stars in the constellation Monoceros. It was recorded by G. D. Cassini before 1711 and independently discovered by Charles Messier in 1772 while observing Biela's Comet. It is sometimes described as a 'heart-shaped' figure or a blunt arrowhead.

M50 is about 2,900 light-years away from Earth and is near to but narrowly not estimated to be gravitationally tied to the Canis Major (CMa) OB1 association. It has a core radius of 1.8 pc and spans 5.46 pc. The cluster has 508 confirmed and 109 probable members – their combined mass is more than $16 arcminute$, the mean stellar density would thus be 1.3 stars per cubic parsec. It is around 140 million years old, with two high-mass white dwarfs and two chemically peculiar stars.