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Moon and Hyades

January 5, 2012

The Moon stares into the face of the bull tonight — the V-shaped pattern of stars that outlines the face of Taurus. It’s below the Moon as night falls.

The brightest star in the V is Aldebaran, the bull’s orange eye. But it’s not “attached” to the rest of the face. Instead, it’s only about half as far as the other stars in the V, which are members of a cluster known as the Hyades.

The cluster contains a few hundred stars, and is centered about 150 light-years away. Its stars are about 650 million years old.

All of its stars were born from a single giant cloud of gas and dust. Today, they move through the galaxy as a family. But as happens with many families, a few of its members are moving out — pulled away by the gravitational tug of the rest of the galaxy. Eventually, much of the Hyades will break up, forming a stream of stars instead of a cluster.

The most prominent members of the cluster are known as Theta 1 and Theta 2 Tauri. They form a close pair about half-way between Aldebaran and the point of the V.

Although the stars look close together, they probably just happen to line up in the same direction in the sky. But both members of the pair are binaries on their own — two stars that are tightly bound to each other. And they’ll probably stick together — whirling through the galaxy as close twins long after they’ve parted company with their other stellar siblings.

More about Taurus tomorrow.


Script by Damond Benningfield, Copyright 2011


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