Feeds

Super-SVELTE BLUSH-PINK planet goes too far with star

Low-mass Jupiter-like exoplanet challenges planetary formation theory

The smart choice: opportunity from uncertainty

Astronomers have detected a low-mass giant planet that challenges existing theories about how bigger worlds are formed.

Jupiterlike low mass exoplanet GJ 504b

Artist's impression ... the Jupiter-like low-mass exoplanet GJ 504b

The Jupiter-sized world, dubbed GJ 504b, was found much further out in its star's orbit than a planet its size should have been, if you go by existing planet-formation theory.

GJ 504b weighs in at around four times Jupiter's mass, and is the lowest mass exoplanet* to be imaged orbiting a Sun-like star using direct imaging techniques.

Given its similarity to Jupiter's size, NASA boffins were surprised to find that it was much much further away than Jupiter is in the solar system's setup: nearly nine times as far, to be exact.

According to existing theory, planets of this size are formed in the gas-rich debris field around a young star. Collisions between asteroids and comets in the disk around the star provide a core seed, which pulls in gas to form a planet when the core reaches sufficient mass to have gravity.

But this model - called "core-accretion" theory - only works well for worlds out as far as Neptune in our solar system, around 30 times further out than the Earth, and not so well once the world is even more distant from its star.

"This is among the hardest planets to explain in a traditional planet-formation framework," said team member Markus Janson, a Hubble postdoctoral fellow at Princeton University.

"Its discovery implies that we need to seriously consider alternative formation theories, or perhaps to reassess some of the basic assumptions in the core-accretion theory."

The team spotted GJ 504busing direct imaging techniques with infrared data from the Subaru Telescope in Hawaii. Direct imaging gives researchers lots of data about exoplanets, but is arguably one of the hardest techniques to manage.

"Imaging provides information about the planet’s luminosity, temperature, atmosphere and orbit, but because planets are so faint and so close to their host stars, it's like trying to take a picture of a firefly near a searchlight," explained Masayuki Kuzuhara at the Tokyo Institute of Technology, who led the discovery team.

GJ 504b orbits the G0-type star GJ 504, which is slightly hotter than our Sun and faintly visible to the naked eye in the constellation Virgo, 57 light years away.

The team estimates that the system is around 160 million years old, with the star at just one-thirtieth its age, compared to the Sun, which is around halfway through its energy-producing life.

"If we could travel to this giant planet, we would see a world still glowing from the heat of its formation with a colour reminiscent of a dark cherry blossom, a dull magenta," said Michael McElwain, a member of the discovery team at NASA's Goddard Space Flight Centre.

"Our near-infrared camera reveals that its colour is much more blue than other imaged planets, which may indicate that its atmosphere has fewer clouds." ®

* Planet which orbits a star other than our Sun

The Power of One Infographic

More from The Register

next story
World Solar Challenge contender claims new speed record
One charge sees Sunswift travel 500kms at over 100 km/h
SMELL YOU LATER, LOSERS – Dumbo tells rats, dogs... humans
Junk in the trunk? That's what people have
The Sun took a day off last week and made NO sunspots
Someone needs to get that lazy star cooking again before things get cold around here
Boffins discuss AI space program at hush-hush IARPA confab
IBM, MIT, plenty of others invited to fill Uncle Sam's spy toolchest, but where's Google?
Bad back? Show some spine and stop popping paracetamol
Study finds common pain-killer doesn't reduce pain or shorten recovery
Forty-five years ago: FOOTPRINTS FOUND ON MOON
NASA won't be back any time soon, sadly
Jurassic squawk: Dinos were Earth's early FEATHERED friends
Boffins research: Ancient dinos may all have had 'potential' fluff
prev story

Whitepapers

Top three mobile application threats
Prevent sensitive data leakage over insecure channels or stolen mobile devices.
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.
Boost IT visibility and business value
How building a great service catalog relieves pressure points and demonstrates the value of IT service management.
Designing a Defense for Mobile Applications
Learn about the various considerations for defending mobile applications - from the application architecture itself to the myriad testing technologies.
Build a business case: developing custom apps
Learn how to maximize the value of custom applications by accelerating and simplifying their development.