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Barnard's Menagerie

August 28, 2010

Few astronomers have a star named after them. Fewer still have an entire galaxy named for them. But one astronomer has both: Edward Emerson Barnard.

Although he was born in Tennessee just before the Civil War, Barnard did most of his astronomical work at Lick Observatory in California, and then at Yerkes Observatory in Wisconsin.

In 1916, Barnard compared a new photographic plate of the constellation Ophiuchus with an old one. He discovered that one star had shifted position from the old plate to the new. That shift indicated that the star is moving across the sky in a hurry, which means that it must be quite close -- just six light-years away. That makes it the second-closest star system to our own, after Alpha Centauri.

Now named Barnard's Star, it's a red dwarf -- a stellar ember that produces far less light than the Sun does. That's why it wasn't discovered until the twentieth century.

South of Ophiuchus is the constellation Sagittarius, which houses Barnard's galaxy. Just as Barnard's Star is one of our nearest stellar neighbors, so Barnard's Galaxy is one of our nearest galactic neighbors. It belongs to the Local Group -- a small cluster of galaxies that includes our own Milky Way. It's an irregular galaxy -- an oddly shaped galaxy with lots of gas and dust, which are spawning new stars.

Barnard's Star -- and Galaxy -- both honor one of the greatest observers astronomy has ever known: Edward Emerson Barnard.


Script by Ken Croswell, Copyright 2010.

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