Moon and Pleiades

Two beautiful objects team up this evening: the Moon and the Pleiades. The little star cluster is close above the Moon. Binoculars will help you pick out some of its brighter stars through the moonlight.

The Pleiades has more than a thousand stars. They were born from the same cloud of gas and dust. But that doesn’t mean the stars are all alike. They come in many varieties. The brightest of them are much more impressive than the Sun.

The brightest of all is Alcyone. It’s about six times the mass of the Sun, and about 2,000 times brighter. And it spins in a hurry — so fast that it bulges outward at its middle. That makes it much wider through the equator than through the poles.

Alcyone is an oddball. The overall cluster is more than 100 million years old. Yet Alcyone appears to be only about 70 million years old. That could mean that it’s been reborn in a way — from the merger of two stars. That would make it look brighter, hotter — and a good bit younger.

The second-brightest member of the cluster is Atlas. It’s actually a triple system — three stars bound by gravity. Two of the stars are quite close together, while the third is far away — it takes about 260 years to orbit the other two.

Again, look for the Pleiades, which marks the shoulder of the bull, above the Moon this evening. Aldebaran, the bull’s bright eye, is to the upper left of the Moon, with the brilliant planet Jupiter well below the Moon.

Script by Damond Benningfield