How do moons form around gas giant planets? This is what a recent study published in The Astrophysical Journal Letters hopes to address as a team of scientists investigated how circumplanetary disks (CPDs) comprised of the gas and dust leftover from planetary formation evolve into moons. This study has the potential to help scientists better understand the conditions for exomoon formation and evolution and where scientists could potentially search for life beyond Earth.
For the study, the researchers used NASA’s James Webb Space Telescope to observe the CPD orbiting CT Cha b, which is located approximately 620 light-years from Earth and is approximately 17 times as massive as Jupiter. The goal of the study was to ascertain the composition of the CPD and compare it to CT Cha b and the surrounding disk of the host star, CT Cha A.
In the end, the researchers found that the CPD around CT Cha b was composed of carbon-rich chemistry that contrasted compositions of gas giant exoplanet atmospheres. Additionally, the researchers found the CPD’s carbon-rich chemistry composition also contrasted with the disk surrounding CT Cha A. The team concluded that this is the first evidence of moon formation around a gas giant exoplanet and compared this to the potential formation mechanism for Jupiter’s Galilean moons.
“We want to learn more about how our solar system formed moons. This means that we need to look at other systems that are still under construction. We’re trying to understand how it all works,” said Dr. Gabriela Cugno, who is a research fellow in the Department of Astrophysics at the University of Zurich and lead author of the study. “How do these moons come to be? What are their ingredients? What physical processes are at play, and over what timescales? Webb allows us to witness the drama of moon formation and investigate these questions observationally for the first time.”
What new insight into moon formation and evolution will researchers make in the coming years and decades? Only time will tell, and this is why we science!
As always, keep doing science & keep looking up!
Sources: The Astrophysical Journal Letters, NASA
Featured Image: Artist's illustration of the elements that orbit the gas giant. (Credit: NASA, ESA, CSA, STScI, Gabriele Cugno (University of Zu00fcrich, NCCR PlanetS), Sierra Grant (Carnegie Institution for Science), Joseph Olmsted (STScI), Leah Hustak (STScI))
