MY Camelopardalis

MY Camelopardalis (MY Cam) is a binary star system located in the Alicante 1 open cluster, some 13 kly away in the constellation Camelopardalis. It is one of the most massive known binary star systems and a leading candidate for a massive star merger. MY Cam is the brightest star in Alicante 1.

The system consists of two hot blue O-type stars with one component having a mass of 32 solar masses and the other 38 solar masses. MY Cam is a contact binary and eclipsing binary, with an orbital period of 1.2 days, and an orbital velocity of 1000000 kph. Both stars share a common envelope.