Beit Algueze (from Ibt al Jauzah)
Armpit of the Giant
"It's that one, the red one." Leslie seemed baffled by my confusion. Together over a quarter century, and I could still amaze her with what I didn't know.
"Red? Stars are just white dots, no?" Until that moment, I had thought so. I looked again.
And just like that, what once was just another star now blazed orange-red.
Betelgeuse glows in the winter sky here in the northern hemisphere, in the constellation Orion. A red supergiant, it is the largest single object I can see naked-eye. Its size varies, the diameter falling somewhere between the diameters of the orbits of Mars and Jupiter.
The light from Betelgeuse travels about 520 years to reach us; we are seeing light generated around the time Martin Luther was born. (An alternate source puts its distance at 425 light years; if so, the photons lighting up our retinas formed about when Sir Francis Drake sailed along the California coast.)
Yad al-Jawza'
The forefoot of the white-belted sheep
Betelgeuse is the 7th brightest star seen on this side of the Earth. When at its brightest, it has the light of 14,000 suns. Most of the star's radiant energy, however, is not in our visible range; if it were, Betelgeuse would be the brightest star in our skies. If honeybees charted stars, this might be their brightest.
Just about all stars we can see (besides the sun) are points of light; in 1995 the Hubble telescope was able to see the star as a disc. A mysterious hot spot, at least 2000 degrees K hotter than the rest of the star, was seen on the star's surface.
Alpha Orionis
Betelgeuse is a variable star, changing its luminosity as it expands and contracts. Its brightest state is twice that of its dimmest. The star appears to have a 420 day cycle of luminosity (though Burnham reports a cycle just over 5 years); one astronomer noted back in 1931 that "there is no law or order in the rapid changes of Betelgeuse."
Jack Horkheimer, host of "Star Gazer" on PBS, a show that specializes in naked-eye astronomy (and was previously known as the Star Hustler until internet search engines gave children a naked-eyeful of starlets), describes the star's fluctuations:
A great big humongous Valentine, a red star slowly beating like a heavenly heart for your sweetheart, courtesy of our local galaxy. And to see it simply go outside any clear Valentine's Night between 8 and 9 p.m., look due south and there you'll see it at its very highest above the horizon. But just to play it safe, and so as not to look like a cheapskate, I still recommend that you purchase that traditional box of chocolates.
Borgil, or Fire-Star
The Hobbits of Middle Earth (Tolkien)
Betelgeuse can be found easily on a clear winter night (or summer for those on the southern half of our planet); "because it hovers almost directly over Earth's equator...it's hidden only from the questionably sane community of scientists who willingly reside at the South Pole." (Berman)
Up high in the southern sky is a band of three stars, known as Orion's belt. Up to the left of the belt is our orange-red giant. To the lower right of the belt is Rigel, a brilliant blue-white star that contrasts nicely with Betelgeuse.
As far as pronunciation, "Beetlejuice" (as in the movie) is close. Indeed the author of the script wrote a letter to Sky & Telescope assuring us his intent:
I'd like to assure all Sky and Telescope readers that the film Beetlejuice, currently in videocassette release from Warner Bros., Inc., does indeed take its title from the red-giant star in Orion. In fact, where the name appears in writing in the film it is rendered in its official form rather than its phonetic one. I should know— I wrote the original script!
Michael McDowell, April, 1989
Tonight my wife is a hundred miles away, and the skies are mostly clear. It is 15 degrees F (-9 C). I will poke my head out briefly. Betelgeuse will glow a warm orange-red as it has done since a cold winter's night not that long ago. My middle-aged eyes can still see what my younger eyes missed.
Sources:
Robert Burnham, Jr., Burnham's Celestial Handbook, Volume Two, Dover Publications, 1978.
Guy Consolmagno and Dan M. Davis, Turn Left at Orion, Cambridge University Press, 1995.
Variable Stars, http://www.aavso.org/vstar/vsots/1200.shtml
Bob Berman, Secrets of the Night Sky,HarperPerennial, 1996.
Jack Horkheimer, "STAR GAZER THE INTERNATIONAL EDITION," http://www.jackstargazer.com/scripts_feb2000.html.