Artist's concept of Fomalhaut, its ring of debris and the Jupiter-type planet observed by Hubble. The planet, called Fomalhaut b, orbits the 200-million-year-old star every 872 years. Click 'play' or scroll above to see second image.
Credit: ESA, NASA, and L. Calcada (ESO for STScI)
This visible-light image from the Hubble shows the newly discovered planet, Fomalhaut b, orbiting its parent star. The image also shows an enormous debris field surrounding the star.
Credit: NASA, ESA, P. Kalas, J. Graham, E. Chiang, and E. Kite (University of California, Berkeley).
WASHINGTON DC: After an eight-year quest for images, the Hubble space telescope has snapped the first visible light images of a planet outside our Solar System.
Found orbiting the star Fomalhaut – 25 light-years away in the constellation Piscus austrinus ('southern fish') – the planet is similar in mass to Jupiter and sits at roughly four times the distance between Neptune and our Sun.
"Our Hubble observations were incredibly demanding. [The planet] is one billion times fainter than the star," said U.S. astronomer Paul Kalas. "We began this program in 2001, and our persistence finally paid off."
Wobbling stars
To date most of our evidence for exoplanets is indirect, and comes from the minute wobble in a star caused by the gravity of an orbiting planet.
But, as they report in the U.S. journal Science today, astronomers including Kalas at the University of California, Berkeley, have now succeeded in capturing the first visible-light images of an exoplanet.
They argue that the planet, dubbed Fomalhaut b, could have a system of rings similar in dimension to the rings Jupiter is predicted to have had, before dust and debris coalesced to form its four main moons.
"Every planet has a chaotic zone, which is basically a swath of space that encloses the planet's orbit and from which the planet ejects all particles," said lead author Eugene Chiang. "This zone increases with the mass of the planet, so, given the size of the chaotic zone around Fomalhaut b, we can estimate that its likely mass is in the vicinity of one Jupiter mass."
See a NASA video here, simulating the erratic orbit of the planet around its star.
Direct proof
Kalas said he suspected the planet's existence back in 2005, when images he took with the Hubble Space Telescope's Advanced Camera for Surveys showed a defined inner edge to the dust belt around Fomalhaut. The edge and "off-centre belt" suggested a planet was in an elliptical orbit around the star.
"The gravity of Fomalhaut b is the key reason that the vast dust belt surrounding Fomalhaut is cleanly sculpted into a ring and offset from the star," Kalas added. "We predicted this in 2005, and now we have the direct proof."
"It will be hard to argue that a Jupiter-mass object orbiting a star like Fomalhaut is anything other than a planet," added co-author James Graham. "That doesn't mean it's exactly what we expected when we went hunting for planets in this system."
The report in Science will be followed by an article to appear in The Astrophysical Journal evaluating interaction between the planet and the dust belt surrounding Fomalhaut.
With AFP.
