A ‘Moon-forming’ Disc Surrounding an Exoplanet is Discovered for the First Time.
A ring of gas and dust orbiting a planet beyond our solar system has been clearly identified for the first time, a discovery that could help clarify how planets and moons are formed, according to a study released Thursday.
The disc encircles an exoplanet known as PDS 70c, one of two gas giants that orbit the star PDS 70, about 400 light years beyond our solar system, and are similar in size and mass to Jupiter.
Using their Very Large Telescope, astronomers from the European Southern Observatory identified PDS 70c in 2019.
According to the study, which was published in The Astrophysical Journal Letters, these observations, along with high-resolution photos from the ALMA telescope in Chile, allowed them to conclude that PDS 70c’s disk contains material that will allow moons to form around the planet.
Since 2006, astronomers have known that the star PDS 70 is encircled by a massive ring of material, but due to technological limitations, they could only guess at the presence of a planet between the star and the ring.
In a press release, the study’s principal author, Myriam Benisty, said, “Our ALMA data were gathered at such precise resolution that we were able to clearly determine that the disc is linked with the planet, and we are able to constrain its size for the first time.”
Researchers are particularly interested in both planets discovered in the system because they are part of a young star system.
PDS 70 is a young star, only 5.4 million years old compared to our Sun, which has been existing for 4.6 billion years.
PDS 70b was found in 2018 by Miriam Keppler, a Max Planck Institute researcher and paper co-author.
“More than 4,000 exoplanets” – planets outside our solar system – “have been discovered to date,” she stated in a press release, “but all of them were detected in mature systems.”
“PDS 70b and PDS 70c, which constitute a system similar of Jupiter and Saturn, are the only two exoplanets discovered thus far that are still forming.”
PDS 70c is surrounded by enough material to build our moon three times over. Jupiter contains four moons and dozens of smaller satellites, despite being a much older planet.