An international team of astronomers, led by Richard Teague, the Kerr-McGee Career Development Professor in the Department of Earth, Atmospheric and Planetary Sciences at MIT, has achieved groundbreaking observations of 15 protoplanetary disks. This effort offers the astronomy community fresh insights into the intricate processes of planetary formation.
“The innovative techniques we’ve developed to capture this data are akin to upgrading from reading glasses to high-powered binoculars—they unveil an unprecedented level of detail within these planet-forming systems,” Teague remarked.
The team’s research findings are available in an open-access study, part of a comprehensive collection of papers published in the Astrophysical Journal of Letters, with more papers slated for release this summer. These results address vital questions, such as methods to gauge a disk’s mass through its gravitational pull and deriving rotational velocity profiles with remarkable precision.
Protoplanetary disks consist of dust and gas surrounding young stars and are the birthplaces of planets. While observing the brighter dust is straightforward, it only provides a snapshot of the underlying dynamics. Teague’s research shifts focus to the gas in these disks, unearthing more details about their gravity, velocity, and mass properties.
To attain the necessary resolution for gas study, the exoALMA program coordinated extended observation sessions with the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile over five years. This collaboration resulted in some of the most exquisite images of protoplanetary disks captured to date.
“The data quality is so exceptional that the community is now developing new tools to extract signatures from planets,” noted Marcelo Barraza-Alfaro, a postdoctoral researcher at the Planet Formation Lab and part of the exoALMA initiative. Numerous new techniques were established to enhance and calibrate the images, fully leveraging the heightened resolution and sensitivity of the observations.
As a consequence, “we’re uncovering new phenomena that challenge our existing understanding of protoplanetary disks,” he added.
One significant paper examines planetary formation through vortices. It has become evident that the simplistic model traditionally proposed—where dust grains coalesce into a planetary core—is inadequate. One intriguing possibility involves vortices, which are localized disturbances in the gas that guide dust towards the center, akin to how soap bubbles converge in a draining tub.
“We can identify where dust is concentrated, but we can’t ascertain its movement,” said Lisa Wölfer, a fellow postdoc in the Planet Formation Lab at MIT and the lead author of the study. While astronomers observe the accumulation of dust, they currently lack sufficient data to determine how it reached that state.
“It’s only through understanding gas dynamics that we can confirm whether a vortex, and not another factor, is shaping the structure,” she explained.
During their data collection phase, Teague, Wölfer, and Barraza-Alfaro constructed simple protoplanetary disk models to compare with their results. However, upon receiving the data, they found their models inadequate.
“The data revealed complexities we hadn’t anticipated,” Teague stated. “Previously, the disks were thought to be static—turns out, that’s far from the truth.”
Faced with this new reality, the team reevaluated their models, opting for more intricate versions that incorporate a greater degree of gas motion. These refined models demand more time and computational resources. However, initial outcomes are promising.
“The patterns appear strikingly similar; we believe this represents a robust case for additional observations,” Wölfer commented.
The publicly available new data arrives at a pivotal moment: ALMA will temporarily cease operations for upgrades in the coming years but astronomers can continue analyzing the data amassed over the years.
“This research will keep yielding findings for many years,” Teague concluded.
Photo credit & article inspired by: Massachusetts Institute of Technology
