M37

M37 is the brightest and also the richest of the 3 open clusters in southern Auriga, containing about 150 stars brighter than mag 12.5, and perhaps a total of over 500 stars. Due to the fact that the cluster contains a considerable number of red giants, and that the hottest main sequence star is of spectral type B9V, this cluster has an estimated age of about 300 million years. Its distance is not known very accurately, and estimates range from 3,600 light years to 4,700 light years. Its apparent diameter of 24' corresponds to a linear extension of about 20 to 25 light years, according to which distance is taken.

Image taken January, 2006.