European Space Agency
Bon Voyage, WASP 18b!
Astronomers say they have detected a planet orbiting another star that appears to be on the verge of plunging into its sun (within the next million years).
The amount of time it has left in the land of the orbiting is far shorter than for any known planet, according to University of Maryland astronomer Douglas Hamilton. If the team reporting the discovery is correct about the planet's future, astronomers should begin to see evidence of a long, very lazy plunge into the star within the next decade, he estimates.
The planet -- WASP-18b -- has 10 times Jupiter's mass, squeezed into an orb about Jupiter's size. The planet is orbiting its star at a distance of just under 2 million miles (Earth is 93 million miles from the sun). That means it's orbiting at an enormous pace: It makes one swing around the star, WASP-18, every 22.6 hours. Surface temperature? Don't even ask! But if you did anyway, the team would tell you it's about 3,800 degrees Fahrenheit. Steel melts at around 2,500 degrees F.
As for the star, WASP-18, it is 326 light years away. It has roughly the same mass and diameter as the sun. But at 630 million years old, it's a young turk. The sun is 4.6 billion years old.
The planet was discovered by an international team of scientists led by Coel Hellier, an astrophysicist at Keele University in Britain. The members are part of the Wide Angle Survey for Planets, an effort that is hunting for planets orbiting other stars using the transit approach. Their network of telescopes looks for the changes in a star's light as a planet passes in front of it, as viewed from Earth. A formal report of their discovery appears in the current issue of the journal Nature.