HR 8799b: Unexpectedly Hot and Cloudy: And About 130 Light Years Away

"Big Alien Planet's Weather Forecast: Hot and Extra Cloudy "
Space.com (August 31, 2010)

"Astronomers peering at a large alien planet have found it to be covered by an atmosphere unlike that of any extrasolar planet yet seen.

"The planet, known as HR 8799b, is about seven times the mass of Jupiter and was discovered in 2008. Since then, astronomers have found little hint of the methane expected in the planet's atmosphere and evidence that it is hotter and cloudier than previously thought.

"The discovery suggests that young gas giants may be cloudier than previously imagined. HR 8799b is among a half-dozen exoplanets that have been directly imaged with telescopes, researchers said...."

Also remarkable: Astronomers used the Keck II Telescope's adaptive optics system to sort out HR 8779b's spectrum from that of its star.

This sort of technology makes it possible to analyze the atmospheres of planets orbiting other stars directly. And get really, really low-resolution pictures of them. The Space.com article includes an image of HR 8799b - that's about three pixels across.

Still: that three-pixel-wide dot is about 130 light-years away. Impressive.