New clues into the birth of 'gas giant' planets
Using the most advanced land telescope, scientists unlock secrets of Jupiter and Saturn
Agence France-Presse in Paris
Astronomers using the most advanced land telescope in the world have unlocked knowledge about how "gas giant" planets such as Jupiter and Saturn came into being.
These vast but uninhabitable worlds are created by gobbling up gas and dust that envelope young stars in a murky disc, they believe.
The evidence comes from observing a youthful star called HD 142527 which is more than 450 light years from earth.
Stars are born from a cloud of cosmic gas and dust, which surrounds the star for millions of years after it bursts into light.
Around HD 142527, the astronomers found an intriguing gap in the dusty disc, and they believe this was carved out by newly-forming gas giants.
The planets absorb the debris into their expanding mass as they circle the star, according to the investigation, published in the journal Nature.
The planets also feast on gas that streams across the gap from the outer zone of the disc to the inner zone, which helps to feed the infant star.
"Astronomers have been predicting that these streams must exist, but this is the first time we've been able to see them directly," said University of Chile astronomer Dr Simon Casassus.
Casassus' team used the Atacama Large Millimetre/submillimetre Array, or ALMA, a hi-tech telescope at the European Southern Observatory's site in Chile's Atacama Desert.
By observing light at submillimetre wavelengths, ALMA is impervious to glare in the infrared or visible-light part of the spectrum.
Using it, the team spotted two dense streams of gas flowing across the gap, as well as residues of gas within the gap itself.
"We think that there is a giant planet hidden within [the gap], and causing each of these streams," said Casassus' colleague, Sebastian Perez.
"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."
The gap itself is huge. It starts at about 10 astronomical units (AUs) from the star - meaning, 10 times the distance of our earth from the sun - and ends at more than 140 AUs.
In a separate paper published by Nature, astronomers using a radio telescope in Parkes, Australia, said an outpouring of gas and charged particles from the centre of the Milky Way is a byproduct of the birth of new stars.