Researchers observe two baby planets guzzling gas from a 'parent' star for first time

The birth of two giant planets guzzling gas as they orbit their parent star has been observed by scientists for the first time.
Seen by Earth's largest radio telescope, vast streams of gas flowing through a gap in a disc of material around a young star seem to support theories of how the planets grow.
The Atacama Large Millimeter / submillimeter Array (ALMA) in Chile's Atacama desert reaches farther beyond the skies than any other radio telescope.

An artist's impression of the disc of gas and cosmic dust around the young star HD 142527. Scientists have made the first direct observations of these streams

The new data published online in Nature are the first direct observations of such streams which are expected to be created by giant planets guzzling gas as they develop.
An international team of astronomers studied a young star known as HD 142527 which lies over 450 light-years from Earth.
It is surrounded by a disc of gas and cosmic dust - the remains of the cloud from which the star formed.

The dusty disc is divided into an inner and an outer part by a gap believed to have been carved by newly forming gas giant planets clearing out their orbits as they circle the star.
The inner disc reaches from the star out to the equivalent of the orbit of Saturn in the Solar System while the outer one begins about 14 times further out.
According to theory, the giant planets grow by capturing gas from the outer disc, in streams that form bridges across the gap in the disc.
Dr Simon Casassus, of Chile University in Santiago, said: 'Astronomers have been predicting these streams must exist but this is the first time we've been able to see them directly.
'Thanks to the new ALMA telescope we've been able to get direct observations to illuminate current theories of how planets are formed.'
The researchers used ALMA to look at the gas and cosmic dust around the star - seeing finer details, and closer to the star, than could be seen with previous such telescopes.
ALMA's observations, at submillimetre wavelengths, are also impervious to the glare from the star that affects infrared or visible-light telescopes.
The gap in the dusty disc was already known, but they also discovered diffuse gas remaining in the gap, and two denser streams of gas flowing from the outer disc, across the gap, to the inner disc.
Researcher Dr Sebastian Perez, also of Chile University, said: "We think there is a giant planet hidden within and causing each of these streams.
"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."

Artist's conception of HD142527 system, where Gas streamers cross a gap in a protoplanetary disk

The observations answer another question about the disc around HD 142527.
As the central star is still forming, by capturing material from the inner disc, the inner disc would have already been devoured, if it was not somehow topped up.
The team found that the rate at which leftover gas streams onto the inner disc is just right to keep the inner disc replenished, and to feed the growing star.