JWST Captures Unprecedented Glimpse of Planet Formation in the PDS 70 System

Victoria, Canada – A groundbreaking study by Canadian astronomers using the James Webb Space Telescope (JWST) has revealed new insights into how planets take shape. Led by University of Victoria Ph.D. candidate Dori Blakely, the study also features major contributions from researchers at the Trottier Institute for Research on Exoplanets (IREx), including Prof. René Doyon, Dr. Loïc Albert, and Prof. David Lafrenière. The team focused on PDS 70, a young star system located 370 light-years away, where two planets are in the process of forming. By leveraging JWST’s powerful capabilities, researchers have uncovered key details about these nascent worlds and the swirling disk of gas and dust from which they are emerging.

A Cosmic Nursery in Action

PDS 70, only five million years old, hosts a disk of material encircling the young star. A prominent gap in the disk marks the location of two growing planets, PDS 70 b and PDS 70 c, which are actively gathering material to build their atmospheres and masses.

“We’re seeing snapshots of the early stages of planetary growth, showing us what happens as worlds compete for survival in their cosmic nursery,” said lead author Dori Blakely, a Ph.D. candidate at the University of Victoria. “What’s remarkable is that we can see not just the planets themselves, but the very process of their formation — they’re competing with their star and each other for the gas and dust they need to grow.”

Innovative Observing Techniques with JWST

To achieve this unprecedented view, the team employed JWST’s Near-Infrared Imager and Slitless Spectrograph (NIRISS) in Aperture Masking Interferometry (AMI) mode. This specialized technique uses a mask with tiny holes to manipulate incoming light, creating an interference pattern that enhances the visibility of faint objects near bright stars.

“This innovative technique is like turning down the young star’s blinding spotlight so you can see the details of what’s around it — in this case, planets,” explained Prof. René Doyon, Director of the Trottier Institute for Research on Exoplanets (IREx) and Principal Investigator for JWST’s NIRISS instrument.

The method proved highly effective, revealing details that would be impossible to detect using conventional imaging techniques.

“This work shows how JWST can do something completely new,” added Dr. Loïc Albert, JWST NIRISS Instrument Scientist at IREx. “We’re using innovative techniques to look at planets in ways we’ve never done before.”

A multi-wavelength view of the PDS 70 system reveals the dynamic interplay between its forming planets (PDS 70 b & c) and their surroundings. The red-yellow glow, based on JWST model data, reveals the growing planets and light scattered off tiny dust grains on the surface of the disk. These dust grains are so small they scatter light mostly forward, which is why we can’t see the far side of the disk. The faint blue ring, captured by the Atacama Large Millimeter/submillimeter Array (ALMA), highlights cooler emission from larger dust grains located throughout the disk. At the heart of the system is the hidden central star, while dashed circles mark the predicted locations of the planets based on earlier, ground-based observations. Credit: Dori Blakely (University of Victoria/NRC)

Witnessing Planetary Growth

The study supports the idea that PDS 70 b and PDS 70 c are still accumulating gas from their surroundings, offering a rare direct observation of planets in their formative years. By analyzing the light emitted in the mid-infrared, researchers measured the brightness and position of the planets with remarkable precision. The results support the theory that planets form through a process called accretion, gradually gathering mass from their surrounding disk.

“These observations give us an incredible opportunity to witness planet formation as it happens,” said Doug Johnstone, Principal Research Officer at the National Research Council of Canada’s (NRC) Herzberg Astronomy and Astrophysics Research Centre. “Seeing planets in the act of accreting material helps us answer long-standing questions about how planetary systems form and evolve. It’s like watching a solar system being built before our very eyes.”

Signs of Moon Formation?

Intriguingly, the data also suggests that the planets may have their own circumplanetary disks—rings of material that could be the birthplace of moons, much like those orbiting Jupiter and Saturn today. JWST’s long-wavelength observations detected extra infrared light around the planets, possibly indicating warm material actively accreting onto them. If confirmed, this would strengthen the case for circumplanetary disks playing a crucial role in shaping planetary systems.

A Glimpse Into Our Own Solar System’s Past

The discoveries in PDS 70 provide a valuable analog to the early evolution of planetary systems, including our own.

“This is like seeing a family photo of our Solar System when it was just a toddler,” said Blakely. “It’s incredible to think about how much we can learn from one system.”

Perhaps the most tantalizing finding was the detection of a faint, unresolved source of light within the disk’s gap. It could be an unknown feature, such as a spiral arm of dust and gas, or even a third planet forming in the system. Future JWST observations with other instruments, such as MIRI and NIRCam, will be essential to unraveling this mystery.

About the Study

This research is part of the NIRISS Guaranteed Time Observations program, led by Dr. Doug Johnstone. The full article is published on February 12, 2025, in The Astronomical Journal and is available at https://iopscience.iop.org/article/10.3847/1538-3881/ad9b94.

We acknowledge financial support from the Canadian Space Agency for this study.

IREx Science Contacts:

Prof. René Doyon

Principal Investigator for NIRISS

IREx Director

Université de Montréal

E-mail

Dr. Loïc Albert

JWST NIRISS Instrument Scientist

IREx Scientist

Université de Montréal

E-mail