Feeds

Stargazers spy retrograde planetary bloater

Bigger than Jupiter, and orbiting backwards

Next gen security for virtualised datacentres

Astronomers have spotted what they claim is the first exoplanet in a retrograde orbit around a star - a bloated body which is also the "least-dense planet currently known".

Dubbed WASP-17b, the body measures 1.5-2 Jupiter radii but weighs in at just half its mass, meaning it's about a dense as polystyrene and "if you could place it in a bathtub, it would bob like a beach ball", as New Scientist nicely puts it.

It's orbiting its star every 3.7 days at a distance of just 7 million kilometres, or "eight times as close as Mercury is to the sun".

What's got the stargazer's excited, though, is that WASP-17b is orbiting in the opposite direction to the star's spin, at an angle of 150 degrees with respect to the plane in which it was born from the cloud of dust and gas which formed the system.

WASP-17b was identified by researchers led by David Anderson of the UK's Keele University, who observed from the South African Astronomical Observatory how it dimmed the star's light as it transited.

Further observations revealed the retrograde orbit. New Scientist elaborates: "If the planet had orbited the star in the same direction as the star spins, it would have blocked some of the light from the approaching side first." The team, however, found the reverse was true.

Three other exoplanets with severely tilted orbits have been discovered, but WASP-17b is the first showing backwards tendencies.

Quite what caused this aberration is unclear. The scientists suggest it may be the result of a near miss with another planet in the system. Team member Coel Hellier of Keele University offered: "A near-collision with the right trajectories can make a gravitational slingshot that flings one of the planets into a retrograde orbit."

Regarding the planet's size, Adam Burrows of Princeton University suggested to New Scientist that tidal forces may be the cause, prompting WASP-17b to "puff up" under the influence of the star's gravity. He said: "It doesn't require too much of this sort of effect to give you radii similar to Jupiter's."

New Scientist has further info here, and the team's findings are published in the Astrophysical Journal here. ®

Secure remote control for conventional and virtual desktops

More from The Register

next story
Our LOHAN spaceplane ballocket Kickstarter climbs through £8000
Through 25 per cent but more is needed: Get your UNIQUE rewards!
LOHAN tunes into ultra long range radio
And verily, Vultures shall speak status unto distant receivers
NASA to reformat Opportunity rover's memory from 125 million miles away
Interplanetary admins will back up data and get to work
SpaceX prototype rocket EXPLODES over Texas. 'Tricky' biz, says Elon Musk
No injuries or near injuries. Flight stayed in designated area
EOS, Lockheed to track space junk from Oz
WA facility gets laser-eyes out of the fog
Volcanic eruption in Iceland triggers CODE RED aviation warning
Lava-spitting Bárðarbunga prompts action from Met Office
LOHAN Kickstarter breaks NINETEEN THOUSAND of your EARTH POUNDS
That's right, OVER 9,000 beer tokens - and counting
prev story

Whitepapers

Endpoint data privacy in the cloud is easier than you think
Innovations in encryption and storage resolve issues of data privacy and key requirements for companies to look for in a solution.
Implementing global e-invoicing with guaranteed legal certainty
Explaining the role local tax compliance plays in successful supply chain management and e-business and how leading global brands are addressing this.
Advanced data protection for your virtualized environments
Find a natural fit for optimizing protection for the often resource-constrained data protection process found in virtual environments.
Boost IT visibility and business value
How building a great service catalog relieves pressure points and demonstrates the value of IT service management.
Next gen security for virtualised datacentres
Legacy security solutions are inefficient due to the architectural differences between physical and virtual environments.