Scientists have for the first time clearly identified a ring of gas and dust surrounding a planet outside our solar system — a discovery that could help reveal how planets and moons formed, according to a study Thursday.
The disk surrounds an exoplanet called PDS 70c, one of two gas giants of similar size and mass to Jupiter orbiting the star PDS 70, about 400 light-years from our solar system.
Astronomers from the European Southern Observatory discovered PDS 70c in 2019 using their Very Large Telescope.
Combined with high-resolution images from the ALMA telescope, also in Chile, the study, published in The Astrophysical Journal Letters, led them to conclude that PDS 70c’s disk has material that would allow moons to form around the planet.
Astronomers have known since 2006 that the star PDS 70 is surrounded by a very large ring of material, but limitations in observing equipment have only allowed them to predict the presence of a planet between the star and the ring.
“Our ALMA observations were obtained at such excellent resolution that we were able to clearly identify how the disk is associated with the planet and constrain its size for the first time,” Myriam Bensty, the study’s lead author, said in a press release.
Both planets discovered in the system are of great interest to researchers because they belong to a young star system.
The PDS 70 star is 5.4 million years old – a spring chicken compared to our Sun, which has existed for about 4.6 billion years.
Miriam Keppler, researcher and co-author at the Max Planck institute, discovered PDS 70b in 2018.
“Over 4,000 exoplanets” — planets outside our solar system — have been found “so far, but all have been detected in mature systems,” the press release said.
“PDS 70b and PDS 70c, which form a system resembling the Jupiter-Saturn couple, are two exoplanets that have been detected so far and are still in the process of formation.”
The material surrounding the PDS 70c is enough to form our moon three times. Jupiter, a much older planet, has four moons and dozens of smaller moons.
by Pierre CELERIER