Plaskett's Star is one of the most massive binary discovered: the primary has a mass of about forty suns, the companion about sixty suns.
J. S. Plaskett, director of The Dominion Astrophysical Observatory near Victoria, B.C., discovered the star's properties in 1922. Plaskett's Star is very probably a member of the close-by cluster NGC 2244.
The star's visual magnitude of 6.05 means that the system isn't terribly difficult to study, although the companion won't be visible. It orbits the primary every 14.396 days.
Plaskett's Star is found southeast of 13 Monocerotis in the same field of view: binoculars.