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Cor Caroli

May 6, 2011

Few stars are named for real people. One of the exceptions is in good view on spring evenings, not far from the handle of the Big Dipper.

Cor Caroli is the brightest star of Canes Venatici, the hunting dogs. German astronomer Johannes Hevelius created the constellation in the 17th century to fill in a fairly barren patch of sky. Its stars represent a pair of hounds held on a leash by nearby Bootes, the herdsman.

The star is actually a binary -- two stars locked in a mutual orbit. Both are bigger, hotter, and heavier than the Sun, and a good bit brighter. They make the system easy to see even though it's more than a hundred light-years away.

The star has lots of names. Most are designations in various catalogs that are used by professional astronomers. For casual skywatchers, though, it's best known by two names. One is Alpha Canum Venaticorum. In this case, the Greek letter "alpha" indicates that it's the brightest star of its constellation.

The other name is Cor Caroli -- a name that means "Charles's Heart." It honors King Charles the Second of England. The name was bestowed by England's Astronomer Royal, Edmund Halley, in 1725. A court official convinced Halley to add the name because he said the star glowed brilliantly at the king's return to London in 1660.

Look for the star in the crook of the Big Dipper's handle. The dipper is high in the sky at nightfall, with the "heart of Charles" to its right, standing almost due east.


Script by Damond Benningfield, Copyright 2011


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