Scientists using the Atacama Large Millimeter/Submillimeter Array (ALMA), in which the National Radio Astronomy Observatory (NRAO) is a partner, have made the first-ever detection of gas in the circumplanetary disk to study planet formation. Moreover, the detection also suggests the presence of a very young exoplanet. The results of the study were published in Astrophysical Journal Letters.
Circumplanetary disks are clusters of gas, dust, and debris around young planets. These disks create moons and other small rocky objects and control the growth of young giant planets. Studying these disks in their earliest stages could help shed light on the formation of our own solar system, including Jupiter’s Galilean moons, which scientists believe formed in Jupiter’s circumplanetary disk about 4.5 billion years ago.
While studying AS 209 – a young star located about 395 light-years from Earth in the constellation Ophiuchus – scientists observed a spot of emitted light in the middle of an empty gap in the gas surrounding the star. This led to the discovery of a circumplanetary disk surrounding a potential Jupiter-mass planet. Scientists keep a close eye on the system because of both the planet’s distance from its star and the star’s age. The exoplanet is located more than 200 AU, or 18.59 billion miles, from its host star, challenging currently accepted theories of planet formation. And if the estimated age of the host star of 1.6 million years holds true, this exoplanet could be one of the youngest ever discovered. Further research is needed, and scientists hope that future observations with the James Webb Space Telescope will confirm the planet’s presence.
“The best way to study the formation of planets is to observe them as they form. We live in a very interesting time when this is happening thanks to powerful telescopes like ALMA and JWST,” said Jahan Bae, professor of astronomy at the University of Florida and lead author of the paper.
Scientists have long suspected the existence of circumplanetary disks around exoplanets, but until recently could not prove it. In 2019, ALMA scientists discovered the circumplanetary disk that forms the Moon for the first time in history while observing the young exoplanet PDS 70c and confirmed the finding in 2021. New observations of gas in the circumplanetary disk in AS 209 may shed further light on the development of planetary atmospheres and satellite formation processes.
The National Radio Astronomy Observatory is a National Science Foundation facility operated under a cooperative agreement with Associated Universities, Inc.