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CHARA
A lovely name for a northern star that vaults the heavens in northern spring, "Chara" from Greek meaning "joy." Not terribly bright, not quite making third magnitude, Chara (the Beta star of the constellation) is the fainter of the pair of stars that dominates the modern constellation Canes Venatici, the Hunting Dogs, invented by Hevelius in the mid- 1600s. The dogs are held by Bootes as he pursues Ursa Major around the pole, Chara and Cor Caroli (the Alpha star) helping make the "southern dog," the "northern dog" represented by a small group of stars to the northeast of Cor Caroli. Chara was originally the name for the southern dog itself, the northern called "Asterion" for "Little Star." But with the brighter of the those that make the southern dog called "Cor Caroli," little Chara got the name to itself. Chara's most interesting aspect is its similarity to the Sun. The principal component of Alpha Centauri, the third brightest star in the sky, is also similar, but it has a bright companion. Chara, on the other hand, like the Sun, seems to be single. The majority of bright naked eye stars are considerably more luminous than the Sun, some vastly so, a natural result of their intrinsic brilliance, such stars visible over great distances. However, our Sun, a modest star in the middle of the full range of stellar brightness, would be invisible to the eye if only 70 light years away. At a distance of 27 light years, Chara provides a good chance to see what the Sun would look like at stellar distances. It is a warm class G star with a temperature of 6,000 Kelvin (only 200 degrees hotter than the Sun), a mass only four percent smaller, and a radius but four percent larger, though it is 25 percent more luminous. Since main sequence hydrogen-fusing stars brighten and swell somewhat as they age, Chara may be one or two billion years older than the Sun. Chara is also detected in the X-ray part of the spectrum, implying that it too has a surrounding hot corona, as expected. Extending the solar similarity, Chara even rotates at a similar speed. The biggest difference, other than luminosity, seems to be a metal content less than solar, the star having only about 60 percent as much iron. So if you want to see the Sun from afar, take a look at Canes Venatici's "southern dog." Could Chara have planets too? We do not know, and for now is not on observing lists that will check the possibility. If it does, our Sun would look almost the same from there as Chara does to us.