Procyon
By human standards, the stars are eternal. Yet every star eventually dies. And the death of one generation of stars has an impact on the generations that follow.
As an example, consider Procyon, in Canis Minor, the little dog. It's in the southeast this evening, to the left of Sirius, the brightest star in the night sky. Procyon actually consists of TWO stars, but only one is visible to the unaided eye -- Procyon A.
Procyon A is one of the brightest stars in the sky, in part because it's only 11 light-years away. Because of that, astronomers from the University of Texas and elsewhere have studied it in great detail. Their observations show that the star contains small amounts of oxygen, carbon, nitrogen, and even iron. These elements tell astronomers that the star is of a fairly recent generation.
The FIRST generation of stars had none of these elements. They were made almost entirely of hydrogen and helium, which were created in the Big Bang. These early stars forged heavier elements in their cores. When the stars died, they expelled some of these elements into space, where they could be incorporated into NEW stars. Each generation of stars has more of these heavy elements than the one before it.
Procyon A is nearing the end of its life -- a stage when IT will begin to make some of these heavier elements. When it dies, it, too will cast many of these elements into space -- elements that will enrich future generations of stars.
Script by Damond Benningfield, Copyright 2003
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