Delta Trianguli

StarDate: November 26, 2009

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The Sun is special. It's the only star we know of that supports life on one of its planets. And the Sun's type is pretty rare: Only one star in 25 is the same type as the Sun.

Just 35 light-years away, though, is another star that's quite like the Sun. It's a member of a pair of stars. The system is known as Delta Trianguli. It's high in the east this evening, in the small constellation Triangulum. Delta Trianguli is so faint, though, that you need a starchart to help you pick it out.

The brighter of the two stars of Delta Trianguli is yellow, like the Sun. And it's a main-sequence star, also like the Sun, which means that it's steadily converting the hydrogen in its core into helium.

The two stars in this system are only 10 million miles apart. That's less than a third of the distance from the Sun to Mercury, the innermost planet in our own solar system.

Unfortunately, because the stars are so close together, astronomers can't see the fainter one. It may be another yellow star, like the Sun, or it may be slightly cooler, so it glows orange.

Because the two stars are so close together, planets could easily go around both. Inhabitants of such a planet would see a double sun in the sky -- and experience double sunrises and sunsets. They might even feel sorry for those who live around our Sun, who must content themselves with a single sunrise and a single sunset each day.

We'll have more about Triangulum tomorrow.

Script by Ken Croswell, Copyright 2009

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