The Celestial Crown

East of Arcturus (arc - of the Big Dipper's handle - to Arcturus) is a beautiful semicircle of stars. This is the Northern Crown, Corona Borealis. The blazing centerpiece of the crown is the star Alphecca, the "Jewel in the Crown." In Greek mythology this crown was given by the god Dionysus to his mortal bride Ariadne.

Ariadne was the daughter of King Minos of Crete. Her mother Pasiphae was also the mother of the Minotaur, a creature half man, half bull. Ariadne fell in love with and saved the hero Theseus from this rampaging man-bull. Alas, she was later abandoned by Theseus.

On the island of Naxos, she met and was comforted by the god Dionysus They fell in love and were married. To seal their love, he gave her a golden crown.

But they were not destined to grow old together. Dionysus, being a god, stayed forever young. But as the years passed, Ariadne, being a mortal, grew old and died. And when she died, in despair, he threw her crown up to the sky.

Modern science also has a fascinating story to tell us. At the center of the crown is the dim star R- Coronae Borealis. It can be seen by the unaided eye, but just barely. Periodically, though, this star grows even dimmer, and is lost to the naked eye. What has happened?

Astronomers discovered it is really a very bright star, but very far away -- thousands of light years. They discovered, too, that its atmosphere was largely carbon: ordinary soot! Most stars, like our own Sun, slowly convert hydrogen to helium. But in their last stages of their lives, when their hydrogen fuel has been depleted, they convert the helium into carbon.

That's what R is now doing. And as it converts the helium in its core to carbon, eruptions in its atmosphere release great clouds of soot, obscuring the star. As the soot dissipates, the star returns to its regular brightness.

Brilliant gems can be covered by the cheapest dust. So can stars.

(02/22/08)