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Astronomers confirm circumplanetary discs

Astronomers have captured, for the very first time, images of a disc of hot gas and dust surrounding a newly formed planet.

An infrared image of the newborn planet PDS 70 b and its circumplanetary disc. The size of the solar system given for comparison. Credit: V. Christiaens et al/ESO

Known as a circumplanetary disc, the phenomenon has long been theorised, but until now has never been conclusively observed.

A team led by Valentin Christiaens from Australia’s Monash University captured the images using the European Southern Observatory’s Very Large Telescope, in Chile.

Their observations, published in Astrophysical Journal Letters,  give an insight into the formation of giant planets and their moons, and provide direct evidence that the theoretical models of planet formation are likely accurate.

Circumplanetary discs are essentially scaled-down versions of much larger ones that surround newly formed stars.  They are thought to be the source of the material for the final stages of planet formation, and for any orbiting moons.

Christiaens and colleagues found theirs by observing a newborn giant planet named PDS 70b, which orbits PDS 70, a star in the constellation of Centaurus, some 370 million light years from Earth.

“Our research helps us to understand how our 4.6-billion-year-old Solar System came about, and how we got here,” says Christiaens.

“We think the large moons of Jupiter and other gas giants were born in such a disc, so our work helps to explain how planets in our solar system formed.”