Feeds

Hubble spies unlikely planet being born in hostile neighborhood

Hoovering a cloud of sand 7.5 billion miles from a tiny star

  • alert
  • submit to reddit

Beginner's guide to SSL certificates

NASA's Hubble Space Telescope has spotted what appears to be a baby planet sweeping up matter from a protoplanetary disk orbiting a red dwarf star some 176 light-years away from Earth.

If, indeed, this planetary formation activity is what the Hubble's Near Infrared Camera and Multi-Object Spectrometer (NICMOS) has observed, the finding raises a number of questions that could redefine current theories of how planets are born.

First, the evidence: Hubble has spotted a "mysterious gap" of 1.9 billion miles in the 41 billion mile-wide protoplanetary disk circling TW Hydrae, a red dwarf that has been known for some time to be surrounded by a disc of gas and other matter.

That gap, NASA says, is likely being caused by an unseen planet that is hoovering up materials and creating a gap in the protoplanetary disk "like a snow plow."

That's all well and good, but there are a few oddities to this particular youngster. For one, it's exceptionally far from its star – about 7.5 billion miles away, the furthest of any of the 900-or-so exoplanets that we earthlings have yet detected. That would place it about twice as far away from TW Hydrae as Pluto is from our Sun (and yes, we've learned from Randy Newman's "A Few Words in Defense of Our Country" that Pluto’s not a planet anymore).

Protoplanetary disk and planetary-formation gap surrounding TW Hydrae

What Hubble's NICMOS saw (left) and what an illustrator imagined (click to enlarge)

According to observations made by the Atacama Large Millimeter Array (ALMA), the dust in the protoplanetary disk beyond 5.5 billion miles from TW Hydrae, well short of the gap, is roughly the size of grains of sand.

"Typically," said John Debes of the Space Telescope Science Institute, who led the gap-finding team, "you need pebbles before you can have a planet. So, if there is a planet and there is no dust larger than a grain of sand farther out, that would be a huge challenge to traditional planet formation models."

And then there's the fact that TW Hydrae is only 8 million years old, and planetary formation takes time – a lot of time. According to NASA, tens of millions of years is a reasonable amount. Due to its slow orbit and diffuse neighborhood, a planet 7.5 billion miles from its star, NASA says, should take about 200 times as long to form as did Jupiter, which is estimated to have taken 10 million years to assemble its gassy self.

Needless to say, if TW Hydrae is but an 8-million-year-old babe, the numbers don't add up.

And then there are the small sizes of both the disk-clearing planet and TW Hydrae itself. The former is estimated to be only between six to 28 times more massive than Earth, and the latter is a stellar pipsqueak, with a mass of only 55 per cent that of our Sun.

"It's so intriguing to see a system like this," said Debes in a bit of an understatement. "This is the lowest-mass star for which we've observed a gap so far out."

It's possible that the planet didn't form in the traditional accretive manner, but its formation was instead initiated when "a piece of the disk becomes gravitationally unstable and collapses on itself," as NASA explains. If this were the case, a planet could form in a relative blink of an eye – say, in a few thousand years.

"If we can actually confirm that there's a planet there, we can connect its characteristics to measurements of the gap properties," Debes said. "That might add to planet formation theories as to how you can actually form a planet very far out."

"Far out," indeed, as we used to say back in the swinging 60s. ®

Internet Security Threat Report 2014

More from The Register

next story
GRAV WAVE DRAMA: 'Big Bang echo' may have been grit on the scanner – boffins
Exit Planet Dust on faster-than-light expansion of universe
SpaceX Dragon cargo truck flies 3D printer to ISS: Clawdown in 3, 2...
Craft berths at space station with supplies, experiments, toys
That glass of water you just drank? It was OLDER than the SUN
One MEELLION years older. Some of it anyway
Big dinosaur wowed females with its ENORMOUS HOOTER
That's right, Doris, I've got biggest snout in the prehistoric world
Japanese volcano eruption reportedly leaves 31 people presumed dead
Hopes fade of finding survivors on Mount Ontake
Relive the death of Earth over and over again in Extinction Game
Apocalypse now, and tomorrow, and the next day, and the day after that ...
prev story

Whitepapers

Providing a secure and efficient Helpdesk
A single remote control platform for user support is be key to providing an efficient helpdesk. Retain full control over the way in which screen and keystroke data is transmitted.
Intelligent flash storage arrays
Tegile Intelligent Storage Arrays with IntelliFlash helps IT boost storage utilization and effciency while delivering unmatched storage savings and performance.
Beginner's guide to SSL certificates
De-mystify the technology involved and give you the information you need to make the best decision when considering your online security options.
Security for virtualized datacentres
Legacy security solutions are inefficient due to the architectural differences between physical and virtual environments.
Secure remote control for conventional and virtual desktops
Balancing user privacy and privileged access, in accordance with compliance frameworks and legislation. Evaluating any potential remote control choice.