dipper@utastro.UUCP (Debbie Byrd) (08/22/84)
The star Deneb is one of the most powerful stars in our galaxy. More about Deneb -- right after this. August 15: The Hen's Tail Of all the stars in the sky, Deneb is one of the most intrinsically luminous. That doesn't mean it's the brightest star visible. A star's appearance depends on two things -- its intrinsic brightness -- and its distance. Deneb doesn't look as bright as the star Vega, located near it in the August sky. But Vega is located only 26 light-years away -- while Deneb shines over a vast space of 16 hundred light-years. To be this far away and this bright, Deneb must be a gigantic star. And so it is. It's what's known as a supergiant star. If Deneb were as nearby as Vega -- only 26 light-years away -- it would be bright enough to cast a shadow and to rival the full moon! If it were as close to us as our sun, we'd be blinded by its light and vaporized by its heat. This magnificent star Deneb, by the way, has a pretty unspectacular name. It's located at one end of the constellation Cygnus the swan -- and its name comes from an Arabic word which means "the tail of the hen." Deneb belongs to the star pattern known as the Summer Triangle. You can probably find the Triangle just by looking for it -- without even consulting a star chart. The triangle is a large star pattern consisting simply of Deneb and Vega -- and of a third star called Altair. It's now located overhead each evening -- and we'll be talking more about it tomorrow. Script by Deborah Byrd. (c) Copyright 1983, 1984 McDonald Observatory, University of Texas at Austin