Original URL: http://www.theregister.co.uk/2013/01/03/gas_giants_form/

Newborn planets spotted slurping up gas from young parent star

Baby giants eat cosmic dust for growth

By Brid-Aine Parnell

Posted in Science, 3rd January 2013 12:43 GMT

Astroboffins have seen a key stage in the birth of giant planets for the first time, as the streams of gas and dust guzzled by newly forming worlds are spotted around a young star.

Artist’s impression of the disc and gas streams around HD 142527

An artist’s impression of the disc of gas and cosmic dust around the young star HD 142527. Illustration by ALMA/M Kornmesser (ESO)

The astronomers have been using the Atacama Large Millimetre/submillimetre Array (ALMA) telescope in Chile to study HD 142527, a young star over 450 light years from Earth.

Boffins reckon that gas giants tear a path through the gas and cosmic dust that are left over from the cloud that formed the star. The planets clear a path through their orbits as they circle the star in the centre, leaving inner and outer rings of cosmic debris.

The huge worlds then grow by sucking up extra bits of dust and gas from the outer circle, in streams that appear to bridge the gap between inner and outer rings, streams that have been spotted around HD 142527.

“Astronomers have been predicting that these streams must exist, but this is the first time we’ve been able to see them directly,” Simon Casassus of the Universidad de Chile, who led the new study, said.

“Thanks to the new ALMA telescope, we’ve been able to get direct observations to illuminate current theories of how planets are formed!”

ALMA makes different observations possible because it views at submillimetre wavelengths, which are impervious to glare from the star picked up in infrared or visible light views. Around HD 142527, the astroboffins have seen two denser streams with ALMA.

“We think that there is a giant planet hidden within, and causing, each of these streams," said Sebastián Pérez, also at Universidad de Chile.

"The planets grow by capturing some of the gas from the outer disc, but they are really messy eaters: the rest of it overshoots and feeds into the inner disc around the star."

While the planets suck up most of what they pull in from the outer gas circle, some of it ends up in the inner circle, where it then feeds the growth of the star.

The full study was published in Nature. ®