Moon and Virgo

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The Moon is passing through the constellation Virgo this week. Tonight, Virgo's brightest star, Spica, is a little to the lower left of the Moon.

A star that's below the Moon is a lot more interesting, though. That's because it has a family of planets -- at least three of them. It's also surrounded by a broad band of dust, which could be concealing more planets.

61 Virginis is a lot like our own star, the Sun. It's about the same size, mass, and temperature. It's a little fainter than the Sun, and it's probably around a billion-and-a-half years older.

And like the Sun, it has a system of planets.

One of the planets is only about five times as massive as Earth. That makes it one of the most Earth-like planets yet discovered. But it's so close to the star that its surface is scorching hot -- too hot for life.

The other planets are a little farther out, but they're still closer than Earth is to the Sun, so they're boiling hot, too. And both of these worlds are much bigger than Earth -- comparable to Neptune in our own solar system. So they, too, are poor prospects for life.

The band of dust around the star is so thick that it could conceal even more planets. But they would also be poor prospects for life -- they're so far out that they're probably ice balls.

61 Virginis rises directly below the Moon, and to the lower right of Spica. Binoculars will help you pluck this tidy but probably barren star system from the Moon's glow.

Script by Damond Benningfield, Copyright 2010

For more skywatching tips, astronomy news, and much more, read StarDate magazine.