The Big Dipper Gains a Star
EmailThe Big Dipper — part of Ursa Major in astronomy — may be one of the most recognized features of the night sky, but that doesn't mean it can't stand an occasional improvement.
A team from New York's American Museum of Natural History, NASA's Jet Propulsion Lab, Caltech, and the University of Cambridge in England reports that Alcor, the bright star that forms the bend in the dipper's "handle," has a dim red dwarf star orbiting it. They've put out this very pretty image, in which Alcor is renamed Alcor A, and its newly-found satellite star is called Alcor B. Click on the image to enlarge.
Neil Zimmerman, a Columbia Ph.D. student, spotted it with the 200-inch telescope at Mount Palomar in California (which used to be the world's largest).
“No one had reported this object before, and it was very close to Alcor, so we realized it was probably an unknown companion star,” said Zimmerman in a statement.
He had to wait a hundred days to see if the interloper was, in fact, moving along with Alcor, or just juxtaposed in the sky much farther away. The second observation sealed the deal. The results are reported in the new edition of The Astrophysical Journal.
The two Alcors are about 80 light-years from us, and Alcor B takes more than 90 years to complete one orbit of its larger companion. In the meantime, they make for a colorful picture.
(Image credit: AMNH/Project 1640)
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The drawing exaggerates the distance between Mizar and Alcor. Telling them apart with the naked eye is a test of excellent eyesight. Showing people that the single “star” they usually see next to the end of the handle is really (at least) two stars is one of the sights in a quick telescopic tour of the sky for beginners.
It’s amazing how many people have no clue of the night sky. Someone writing to one of the major astronomy magazines said he showed his real estate agent the moon through his telescope. Astonished, she said, “Does the government know about this?”
Posted by: The_Mick | December 10, 2009, 11:10 am 11:10 am
That’s not what they’re talking about Mick. Anyone that doesn’t live in a light pulluted area can see the two starts in the handle bend quite clearly. What they’re saying is that there are actually three starts in that bend, with this “new” star orbiting the top star.
Posted by: moderateguy | December 10, 2009, 12:00 pm 12:00 pm
Demonstrating astronomy to Cub scouts, not many parents have any other understanding of the universe except maybe naming planets of our system and even then I don’t think they understand what a planetary system is. I would think that anybody growing up since the space program became big in the U.S. should know more than that merely through absorption.
Posted by: rwsmith | December 10, 2009, 2:55 pm 2:55 pm
I am sure that some non serious UFO researches will talk about Alcor B as an UFO object.Congratulations to Mr Zimmerman.
Posted by: Manuel Berggrun | December 21, 2009, 2:07 pm 2:07 pm
Well, this is a pretty neat find, but I’ve been an astronomy fan since I was a kid — going back to the 1950′s (Yes, I remember Sputnik — electrifying stuff!), so of course this interests me. regarding the comments how little people know about the skies, I’ve found that so true. I married a native of Beijing when I lived there in the late 1980′s, and one dusk, aware Venus or Jupiter (I forget which) was very near the crescent Moon, I mentioned it to my wife and said she ought to walk outside with me to see it. She did — but was dumbfounded we could see the crescent Moon while the Sun was still above the horizon. And she was *educated* and herself a university teacher, though in language, not the sciences. Some years later, I pointed out the rising Moon to a friend while the Sun was still visible, and she was equally dumbfounded, and didn’t really believe it until her [farmer] Father confirmed it to her, himself incredulous she didn’t already know that. But really taking the cake was the otherwise intelligent man who absolutely refused to believe there is no “dark side” of the Moon, not in the sense people believe it. He had the good fortune to witness a total eclipse while traveling abroad — and came home, triumphantly announcing he could PROVE there was a dark side of the Moon — he PHOTOGRAPHED it. (He indeed got some lovely photos, but just couldn’t grasp the plot of why the Moon was dark on the earthward side at that moment.) Sigh . . .
Posted by: Mekhong Kurt | February 2, 2010, 1:55 pm 1:55 pm