A modest but unusually attractive open star cluster in Canis Major, NGC2362 hosts some of the youngest-known stars, some of which are still contracting and settling onto the main sequence. This open cluster contains many faint stars centered on the bright star tau Canis Majoris; in a telescope, the cluster looks like a large diamond set among many smaller blue-white gems. Very pretty.
• With a diameter of 8 light years, NGC2362 is about the same size as the Pleiades. But it’s about 4,500 light years away, some 10x farther than the Pleiades, so it spans only 1/4 degree of sky and is much fainter.
• This cluster is fairly easy to find, below Sirius in the “hindquarter” of the Great Dog, Canis Major. Look for a triangle of stars below Sirius. The cluster is 3 degrees northeast of the top star, Wezen, in the triangle; it’s well positioned right now in the early evening for stargazers in most parts of the world except for the far north.
NGC 2362 (left middle)
• In binoculars, NGC2362 looks like a fuzzy appendage to tau CMa; use a small telescope at 50-60x to resolve the cluster into glittering blue-white suns.
A Deeper Look
• Most of the stars you see are massive O and B stars, all of which are 1000-1500x brighter in real terms than the sun.
• Because of their mass, O and B stars evolve quickly into red supergiants. But there are few such stars in this cluster, which means it is likely a very young cluster… less than 5 million years old.
• Astronomers have used the Chandra X-Ray space telescope to determine many stars in NGC2362 are still surrounded by primordial disks of gas and dust that fall onto the central stars, even after millions of years.
Good To Know
This pleasant-looking cluster will stay together longer than the Pleiades before its stars disperse into the galaxy. And like many stars in this part of the sky, several members of NGC 2362 will one day detonate as supernovae, putting on quite a show in our skies in the coming millenia.
Just a degree or two north of this cluster, you’ll find a fine double star that’s sometimes called “the Winter Albireo”. Known as Herschel 3945, this binary has reddish and golden-yellow components that look lovely in a telescope. Although this star is visually fainter than the real Albireo, it’s proximity to NGC 2362 makes it easy to find.