The constellation Auriga is high in the eastern sky as night falls. It’s usually drawn as a pentagon. The brilliant star Capella is at the top left corner, with fainter Elnath – a star that’s shared with Taurus – at the lower right.

A trail of three prominent star clusters winds through the pentagon – Messier 36, 37, and 38. M36 and 38 are inside the pentagon. M37 is just below it. All three are easy targets for binoculars.

M37 is about 4500 light-years away. And it’s the largest of the trio of clusters. It spans a few dozen light-years. Astronomers have cataloged more than 500 member stars, but the total population could be much higher. The cluster includes more than 50 dead stars known as white dwarfs. The details of such stars help reveal the cluster’s age – roughly 400 million to 550 million years.

And that’s a long time for a star cluster to hang together. M37 has orbited the center of the Milky Way Galaxy at least twice. As it orbits, the gravitational fingers of other stars and gas clouds pull away some of the stars on the fringes of the cluster.

So far, Messier 37 appears to be maintaining a firm grip on most of its stars. But that won’t last forever. More stars will be pulled away on each trip through the galaxy – whittling down this tight family of stars.

Script by Damond Benningfield