New insights into the formation of gas streams that propel the growth of infant stars have been unveiled by astronomers with help from NASA’s James Webb Space Telescope, revealing deeper insights into how they feed on material from their surrounding disks.
The new findings are offering astronomers unprecedented new details about young stars and planets, and the processes that give rise to their formation and evolution over time.
The new research focused on investigations into the structure of gas flows in protoplanetary disks, which are the massive, dusty clouds of gas surrounding newly formed stars. Based on recent Webb telescope data, researchers involved were able to confirm the existence of a previously “hidden” mechanism that astronomers have long suspected to be behind what allows stars to gain mass as they grow.
Revealing a Magnetic Mystery
Detailed in a new paper in Nature Astronomy, the new research, led by scientists from the University of Arizona and supported by the Max Planck Institute for Astronomy, reveals that magnetic winds play a key role in transporting material that helps stars grow, along with shaping the mass present in their surrounding disk into a planetary system.
The unprecedented clarity of Webb’s instruments allowed the team to produce highly detailed insights into these long-theorized processes underlying star and planetary formation. With the help of magnetic fields propelling them, these winds, composed of channels of gas expelled from the planet-forming disk, can cover large distances—as much as several dozens of kilometers—in just a single second.
Webb Reveals New Insights Into Protoplanetary Disks
Often likened to planetary nurseries by astronomers, protoplanetary disks are the gas and dust-filled structures surrounding young stars. Over time, the material in these discs begins to accumulate into condensed regions that eventually form neighborhoods of planets resembling our solar system.
The primary phenomena behind these processes have long remained mysterious to astronomers, and the new findings by the University of Arizona and Max Planck Institute collaboration help to provide crucial details about this mystery, thanks in large part to Webb’s capabilities that made tracking the movement of gas in the disks possible.
As magnetic fields drive the powerful winds, gas is transported outward and away from the disk, allowing the central star to attract mass toward it and grow.
Ilaria Pascucci, a professor at the University of Arizona’s Lunar and Planetary Laboratory and lead author of the study, explained that the team’s new research reveals the critical role these magnetic disk winds play in the evolution of the entire system, which influence not only star growth but also planet formation.
“How a star accretes mass has a big influence on how the surrounding disk evolves over time, including the way planets form later on,” Pascucci recently said in a statement.
“The specific ways in which this happens have not been understood,” Pascucci added, “but we think that winds driven by magnetic fields across most of the disk surface could play a very important role.”
Another significant aspect of the new findings involves the detection of different kinds of winds, which include thermal winds the team identified that are caused by starlight. These thermal winds originating from stellar illumination are slower than the winds driven by magnetic fields.
The Webb data allowed Pascucci and the team enough information that differences between these winds could be discerned, further clarifying the processes shaping the evolution of protoplanetary disks.
An Astronomical First
Never had astronomers been able to obtain imagery of the nested structure of these winds in such detail, and the team’s new observations lend new weight to the theory that magnetic fields play a critical role in removing angular momentum from the disk.
As this momentum is reduced, gas is allowed to spiral inward, falling onto the central star. The team now feels confident that the recent observations help to confirm this long-held theory, offering key insights into the early conditions in our solar system that eventually led to its current appearance.
As a next step, the team says they will expand their observations to include more protoplanetary systems, where they hope to obtain additional information with the aid of the Webb telescope into how widespread magnetic disk winds may be.
“We want to get a larger sample with JWST and then also see if we can detect changes in these winds as stars assemble and planets form,” Pascucci said.
With additional insights into how these winds evolve throughout the process of stellar evolution and planetary formation, future studies may be able to provide even deeper insights into the origins of planetary systems and, ultimately, a clearer picture of how planets like Earth and our surrounding planetary neighborhoods are created.
The team’s recent paper, “The nested morphology of disk winds from young stars revealed by JWST/NIRSpec observations,” was published on October 4, 2024, in the journal Nature Astronomy.
Micah Hanks is the Editor-in-Chief and Co-Founder of The Debrief. He can be reached by email at micah@thedebrief.org. Follow his work at micahhanks.com and on X: @MicahHanks.