Astronomers are reporting that they have successfully taken the first-ever photographs of planets outside of our solar system. Photographs of extrasolar planets have been attempted before, but yielded no firm results. This time, they’ve captured images of four planets in two systems: there’s a visible-light snapshot of a single-planet system, and an infrared picture of a triple-planet system.
From Space.com, regarding the triple-planet system:
The trio of worlds orbits a star named HR 8799, which is about 130 light-years away in the constellation Pegasus and about 1.5 times as massive as the sun. The planets are located at distances from their star of 24, 38 and 68 astronomical units (AU). (An astronomical unit equals the average Earth-sun distance of 93 million miles, or about 150 million km.) Other planet-finding techniques work out to only about 5 AU from a star.
The planet closest to the star weighs in at 10 times the mass of Jupiter, followed by another 10 Jupiter-mass planet and then, farther out, a world seven times the heft of Jupiter.
And regarding the single-planet system:
University of California, Berkeley, astronomer Paul Kalas led the team of astronomers who took the visible-light snapshot of the single-planet system. The exoplanet has been named Fomalhaut b, and is estimated to weigh no more than three Jupiter masses.
The Hubble Space Telescope’s Advanced Camera for Surveys was used to make the image. The camera is equipped with a coronagraph that blocks out the light of the host star, allowing astronomers to view a much fainter planet.
Fomalhaut b is about 25 light-years from Earth. Photos taken in 2004 and 2006 show the planet’s movement over a 21-month period and suggest the planet likely orbits its star Fomalhaut every 872 years at a distance of 119 astronomical units (AU), or 11 billion miles (nearly 18 billion km). That’s about four times the distance between Neptune and the sun.