Radio telescopes have carried out observations of the near-planetary disk of the gas giant PDS 70c - an accumulation of gas and dust, where its future satellites are born.
Two years ago, astronomers working with the ALMA radio telescope array received the first images of the near-planetary disk of the distant exoplanet PDS 70c. It is a young, not yet fully formed gas giant about 370 light-years distant. And recently, with the help of ALMA, it was possible to obtain more detailed images of its disk - gas, dust and debris accumulated in orbit around the young planet. Scientists write about this in an article published in the Astrophysical Journal Letters.
“Our paper presents a clear disc detection in which satellites can be formed,” says Myriam Benisty, one of the authors of the paper. - ALMA images are taken at such a high resolution. We can clearly determine that the disk is associated with the planet, and for the first time estimate its size. " According to her, past observations did not allow to unambiguously separate the disk from the surrounding background.
The exoplanet is near the young variable star PDS 70 in the constellation Centaurus. Its two exoplanets were discovered in 2018 and 2019, they are also extremely young and both belong to the class of gas giants, like our Saturn and Jupiter.
New ALMA data showed that the PDS 70c circumplanetary disk stretches up to 1.2 astronomical units (the average distance from the Earth to the Sun) and contains enough material to form three satellites the size of our moon. At the same time, scientists were able to examine the neighboring planet PDS 70b - unlike PDS 70c, they did not find any disk in it. Most likely, most of the material from the orbit of PDS 70b was pulled by a larger neighbor.
The dynamics of the exchange of matter between the young planet and the near-planetary disk largely determines its further evolution and the appearance of satellites. Therefore, such observations are extremely important for understanding the formation of planets and satellites, and scientists will continue to study the PDS 70 system.
“To date, more than 4,000 exoplanets have been found, and they are all in mature systems,” said Miriam Keppler, another co-author of the study. "The planets PDS 70b and PDS 70c, forming a system that resembles a pair of Jupiter-Saturn, is the only example of exoplanets that are still forming."