Vega

One of the most brilliant stars in the night sky is a dominant presence from late spring through autumn. Vega is the fifth-brightest star in all the night sky. It’s about a third of the way up in the east-northeast at nightfall now, and climbs high overhead later on.

Vega is just 25 light-years away — a close neighbor. That’s one reason it appears so bright. But it really is an impressive star. It’s more than twice as big and heavy as the Sun, and about 40 times brighter.

Vega is encircled by a disk of dust. Such disks can provide the raw materials for planets. Vega is already about 450 million years old, though, which is well beyond the expected planet-birthing years. So the disk isn’t likely to spawn any new planets.

But Vega might already have a planet.

Astronomers looked at a decade of observations of Vega. The observations ruled out many possible types of planets — including one that was hinted at in some earlier work. But they did suggest that a planet about 20 times the mass of Earth orbits Vega every two and a half days.

The discovery isn’t especially solid. But if the planet’s really there, it orbits Vega roughly around its poles, not around the equator, as Earth orbits the Sun. And it’s so close to Vega — a hot, bright star — that it would be one of the hottest planets yet seen: roughly 5400 degrees on its dayside — a broiling planet around a hot star.

More about super-hot planets tomorrow.
 

Script by Damond Benningfield