Auriga Clusters

The bright yellow-orange star Capella stands about a quarter of the way up the northeastern sky at nightfall. It’s the leading light of Auriga the charioteer. Capella links with the constellation’s other major stars to form a hexagon, which spreads out below and to the right of Capella at that hour.

Several star clusters reside in or near the hexagon. These are families of scores to hundreds of stars. Each family is bound together by the stars’ mutual gravitational pull.

The best-known clusters are Messier 36, 37, and 38. They’re easy targets for binoculars.

M37 is the brightest of the three, even though it’s about 4500 light-years from Earth. It stands a little below the hexagon. The cluster contains more than 500 stars, all of which may be up to 500 million years old. M36 contains about half as many stars, and is only about 25 million years old. And M38 is smaller still, and about halfway between the ages of the other two.

Over the eons, all three clusters will lose some of their stars. Those at the edges of a cluster are more loosely bound than the ones near the center. The gravitational “fingers” of the rest of the galaxy’s stars and gas clouds eventually will drag the stars away. In fact, it’s possible that one or more of the clusters could completely disintegrate. All of their stars would then go their separate ways — leaving their stellar homes for the wide-open spaces of the galaxy.

Script by Damond Benningfield