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Moon and Scorpius

July 27, 2012

Although the Sun is a star, just like all those twinkling points of light in the night sky, not many stars closely resemble it. Most stars are much fainter than the Sun, while a few are much brighter; most stars are cooler, while a few are hotter; and most stars are a good bit younger or older. But a few stars are near twins to the Sun, including one that’s visible in the southwestern sky tonight: 18 Scorpii, which is faintly visible to the unaided eye.

Astronomers in Brazil reported the star’s remarkable similarity to the Sun in 1997. They found that its light output was nearly identical to the Sun’s, as were its color, temperature, and mass. It’s also about the same age as the Sun, with a similar abundance of heavy, planet-forming materials, so it could have a planetary system like ours. So far, no one has actually discovered planets orbiting 18 Scorpii, but the search continues. And if any planets orbit the star at about the same distance that Earth is from the Sun, conditions could be just right for life.

18 Scorpii is just 45 light-years away, so it’s visible to the unaided eye — if you have a dark sky and know just where to look. As darkness falls tonight, it’s high above the lineup of the Moon and the beautiful orange star Antares to its left or lower left. A good star map should show you the way from Antares to 18 Scorpii — a near neighbor to our Sun in more ways than one.

We’ll have more about the Moon and Antares tomorrow.


Script by Ken Croswell, Copyright 2012


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