Moon-forming space dust spotted swirling around planet in another solar system
WASHINGTON: Scientists for the first time have spotted a moonforming region around a planet beyond our solar system - a Jupiter-like world surrounded by a disk of gas and dust massive enough that it could spawn three moons the size of the one orbiting Earth.
The researchers used the ALMA observatory in Chile’s Atacama desert to detect the disk of swirling material accumulating around one of two newborn planets seen orbiting a young star called PDS 70, located a relatively close 370 light years from Earth.
A light year is the distance that light travels in a calendar year - about 9.5 trillion km.
More than 4,400 planets have been discovered outside our solar system, called exoplanets. No circumplanetary disks had been found until now because all the known exoplanets resided in “mature” - fully developed - solar systems, except the two infant gas planets orbiting PDS 70.
“These observations are unique - so far - and have been long waited for, in order to test the theory of planet formation and directly observe the birth of planets and of their satellites,” said astronomer Myriam Benisty of University of Grenoble, who led the study published on Thursday in Astrophysical Journal Letters.
In our solar system, the impressive rings of Saturn, a planet around which more than 80 moons orbit, represent a relic of a primordial moonforming disk, said study co-author Stefano Facchini of the European Southern Observatory. The orange-coloured star PDS 70, roughly the same mass as our sun, is about 5 million years old - a blink of the eye in cosmic time. The two planets are even younger.
Both planets are similar to Jupiter, although larger - a gas giant that is our solar system’s biggest planet. It was around one of the two planets, called PDS 70c, that a moon-forming disk was observed.