Messier 41 (also known as
M41 or
NGC 2287) is an
open cluster in the
Canis Major constellation. It was discovered by
Giovanni Batista Hodierna before 1654 and was perhaps known to
Aristotle about 325 BC. M41 lies about four degrees almost exactly south of
Sirius, and forms a triangle with it and
Nu2 Canis Majoris—all three can be seen in the same field in binoculars. The cluster itself covers an area around the size of the full moon. It contains about 100 stars including several
red giants, the brightest being a
spectral type K3 giant of apparent magnitude 6.3 near the cluster's center, and a number of white dwarfs. The cluster is estimated to be moving away from us at 23.3 km/s. The
diameter of the cluster is between 25 and 26
light years. It is estimated to be 190 million years old, and cluster properties and dynamics suggest a total life expectancy of 500 million years for this cluster, before it will have disintegrated.