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Photo Astronomers first spotted what appears to be a ring of matter forming the moon around a young exoplanet, and described their findings in an article published Thursday.
Orbiting a star 400 light years away, PDS 70c is an otherworldly Jupiter-like gas giant that is of particular interest to observers of the planet. Unlike most other confirmed exoplanets, PDS 70c and its neighbor PDS 70b are not yet fully developed. So much so that when they were discovered in 2018 and 2019 respectively, it was the first time that researchers could directly image a protoplanet.
The latest observations have confirmed that the PDS 70c is home to another astronomical gem: it’s surrounded by a cloud of gas and dust in which satellites are slowly taking shape.
“Our work presents a clear detection of a disk in which satellites could form,” said Myriam Benisty, first author of the article and researcher at the University of Grenoble, France.
Left: Image taken by the ALMA telescope of the system surrounding the central star PDS 70. The bright rings are where the planets, PDS 70b and PDS 70c form. Right: Close-up of the luminous point: the lunar disk around the PDS 70c. Image credit: ALMA (ESO / NAOJ / NRAO) / Benisty et al. Click to enlarge
In 2019, Benisty and his colleagues suspected that they had caught a glimpse of the blurred outline of a circumplanetary disk around the exoplanet. Now they are sure of it after being able to see it more clearly with the ALMA telescope in the Chilean desert.
“Our ALMA observations were obtained at such exquisite resolution that we were able to clearly identify that the disk is associated with the planet and we are able to constrain its size for the first time,” she said.
The disc forming the moon measures roughly the same distance from our Sun to Earth in diameter and has sufficient mass to form up to three moon-sized satellites. However, it is not known how many moons will eventually orbit PDS 70c.
Astronomers believe that satellites are created in the same way as planets. The particles of gas and dust collide and agglomerate to form an accretion disk that gradually grows larger. Evidence for these so-called circumplanetary disks, where planets originate, has been spotted around stars, but circumplanetary disks, where moons originate, have rarely been seen.
“These observations are really the first where we have been able to truly identify the presence of a circumplanetary disk – so far we have had no definitive proof of their existence,” co-author Richard Teague, Harvard & Smithsonian’s fellow Center for Astrophysics, said The Reg.
“Beyond that, we can measure the size and mass of the disk, providing clues about the internal structure and the likelihood of that disk forming moons. Also, since we have such wonderful data on the circumstellar disk, we can place all of these constraints in the context of the larger circumstellar disk to understand if the environment is similar to those the theories predict are most likely to be. to form circumplanetary disks.
The researchers believe that the two exoplanets, PDS 70c and PDS 70b, provide good environments to study the conditions necessary for the formation of moons.
“One of the great puzzles of this system is the difference between the two planets. Both planets were detected in the near infrared, but only PDS 70c appears to have a clear circumplanetary disk around it. We want to better understand the difference between these two planets, ”added Teague.
“Is the PDS 70c starving the PDS 70b, for example?” Could it accumulate all the material from the circumstellar disk before the PDS 70b has a chance? Having the opportunity to study an example of a moon-forming disc is great, but [the planetary system] is unique in that it allows us to study two, and the interaction between them. ®
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