70 Ophiuchi

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The summer sky features the large but inconspicuous constellation Ophiuchus, the serpent bearer. It fills a large wedge of the southwestern sky at nightfall. It's tough to pick out, though, because none of its stars is all that impressive -- to look at, anyway. But one of its star systems is intriguing because conditions there could be just right for life.

It's known as 70 Ophiuchi. It's a binary system that's just 17 light-years away. Both of its stars are orange dwarfs, which means they're a little cooler and fainter than the Sun.

Their orbit around each other is stretched out by quite a bit. At their farthest, they're nearly as far apart as Pluto is from the Sun. At their closest, they're only about a third of that distance.

That means there's room for each star to have several planets with orbits similar to those of Earth and its neighboring worlds. And recent research indicates that 70 Ophiuchi is older than the Sun. That means that life has had plenty of time to establish itself.

The new research examined how the surfaces of the stars vibrate up and down. Just as earthquakes probe Earth's interior, stellar vibrations probe a star's interior. A star's interior changes as it ages, so studying these vibrations lets astronomers measure the stars' ages: about six billion years -- a billion and a half years older than our own solar system.

So who knows? Maybe when you look at Ophiuchus tonight, someone else might be looking back.

Script by Ken Croswell, Copyright 2008

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