First Extrasolar Planets Caught On Camera

Morning Edition, November 14, 2008 · Astronomers are getting their first real glimpses of planets in orbit around distant stars.

Over the past decade, more than 300 otherworldly worlds have been detected indirectly — typically their gravitational pull makes their host-stars wobble and astronomers can pick up that wobble. But the most recent planet discoveries are actual photo-ops.

For the first time, scientists have produced images of multiple planets orbiting a star other than our own sun. There have been three reports in the past two months purporting to show images of planets in solar systems around nearby stars.

Science Express published two of the new finds online Thursday. One involves a planet that appears to be orbiting just inside a giant ring of gas that encircles a star known as Fomalhaut, a mere 25 light-years from Earth. Paul Kalas of the University of California, Berkeley, suspects the planet is shepherding the star's massive gas ring and keeping it organized, much the way "shepherd moons" circle the rings of Saturn and keep them tidy.

The planet, dubbed Fomalhaut b, is a gas giant that is much bigger than Jupiter and apparently is surrounded by rings of its own. It's more than 100 times farther from its star than Earth is from the sun.

Meanwhile, an international team of astronomers say they've seen not just a single planet, but a small solar system around a star called HR 8799 (The name might sound like a personnel form, because astronomers sometimes can't decide whether to be scientific or romantic.)

These three planets in this system also appear to be gas giants, and all are at least five times bigger than Jupiter. Their orbits aren't too different from the orbits of our own outermost planets. And that makes this solar system somewhat like our own — though the star and its planets are much younger than our 5 billion-year-old solar system.

"Not only is it exciting just because we have pictures for the first time, but also because these pictures are revealing an entirely new population of planets that were not accessible to the previously used method for planet detection," says Ray Jayawardhana, an astronomer at the University of Toronto. He was part of a team that in September announced yet another image of what it claims is a planet at a nearby star.

But astronomers have not found what they would dearly like to see: an earth-like planet around a sun-like star.

"That's a little ways away, I'm afraid," Jayawardhana says.

We'll probably have to wait for the space telescope that will replace Hubble sometime in the coming decade.