Beyond Earth

Astronomers make the first observations of a ‘moon-forming’ disk around a distant planet

CNN  — 

The story of exoplanet PDS 70 c, the focus of the first confirmed image of a newborn planet still forming in our galaxy, becomes curioser and curioser.

Astronomers have now made the first observations of a moon-forming disk around the planet in a star system 370 light-years away.

Last month, astronomers photographed PDS 70 c and another exoplanet, PDS 70 b, discovering that two juvenile exoplanets are still growing as they orbit the young star PDS 70. This is only the second system with more than one planet to be captured in an image.

The star is 6 million years old. PDS 70 is smaller and less massive than our sun, and it’s still gathering material. Around the star, there’s a large disk made of gas and dust. And carving out a wide gap within that disk are the two planets, PDS 70 b and PDS 70 c. The gap is between 1.9 billion and 3.8 billion miles.

Both planets are massive Jupiter-like gas giants. And new observations by the Atacama Large Millimeter/submillimeter Array revealed evidence of a dust-filled disk around PDS 70 c that could form multiple moons.

“Planets form from disks of gas and dust around newly forming stars, and if a planet is large enough, it can form its own disk as it gathers material in its orbit around the star,” said Andrea Isella, an astronomer at Rice University in Houston and lead author of a paper describing the disk that was published in the Astrophysical Journal, Letters. “Jupiter and its moons are a little planetary system within our solar system, for example, and it’s believed Jupiter’s moons formed from a circumplanetary disk when Jupiter was very young.”