A team of astronomers, led by University of Warwick in collaboration with researchers at MIT and McMaster, have developed a novel method to use the properties of dust rings around stars to estimate the masses of newborn planets. Published in The Astrophysical Journal , this research offers astronomers a new way to find and characterise planets that are too deeply embedded in their birth environment to be seen directly.
Swirling disks of gas and dust surrounding young stars are the environments in which planets form. New powerful telescopes, such as ALMA , have revealed that many of these protoplanetary disks contain striking ring-shaped structures. These have long been suspected to be clues to the planets potentially orbiting within the disks, but until now robust methods to interpret them have proved elusive.
"These bright rings are not just beautiful structures - they are essentially planetary fingerprints," said lead author, Amena Faruqi, PhD student, Astronomy and Astrophysics Group, University of Warwick. "We’ve long understood that the rings could be created from concentrated dust that piles up just beyond the orbit of young, embedded planets, but we’ve been so far unable to link features of these rings to planet masses.
By reading ‘between the rings,’ we have now found a way to reconstruct the masses of the planets that create the rings, even when those planets are too faint or too embedded to observe directly.”
The research team used detailed computer simulations to determine how planets of different masses shape the dust rings around them. They discovered that a ring's width, the location of its brightest point, and the amount of dust it contains all carry tell-tale signatures of the planet responsible.
Crucially, the team identified a simple mathematical relationship between the location of a ring's brightness peak and the mass of its host planet, one that holds regardless of the observing wavelength or the size of the dust grains being imaged. This implies that astronomers can apply the method to existing observations without needing detailed knowledge of disk conditions.
To validate their approach, the researchers applied their method to PDS 70 , one of the few systems where planets have been directly imaged inside their disk. They recovered a mass for the planet PDS 70c that is in strong agreement with independent estimates. They also applied the technique to five disks from the recent exoALMA survey , predicting new mass estimates for the planets potentially lurking within them.
Co-author Dr Jessica Speedie, 51 Pegasi b Postdoctoral Fellow, Massachusetts Institute of Technology (MIT) added: “One of the strengths of this work is that it doesn't stay in the realm of theory - we've been able to take these simulation results and apply them directly to real observed systems. Using the PDS 70 system as an observational laboratory in particular enabled a real verification of the approach, giving us confidence that these methods are genuinely ready to be applied widely as soon as possible. "
The findings open up new possibilities for disk observations that will help confirm the existence of planets suspected to be lurking in disks, reveal entirely new ones, and could shed light on processes which may have played a role in the formation of our own Solar System.
Senior co-author Professor Emeritus Ralph Pudritz, Department of Physics and Astronomy, McMaster University: “Another striking result of the simulations is that, in typical discs, more massive forming planets can trap as much as 20 times the mass of Earth of dust within these rings. This confirms ALMA observations – but raises the question of why new planets have not been detected in the trapped dust and pebbles of the ring. Our results suggest that the dust is sufficiently abundant and concentrated enough to potentially kick-off planet formation. This is an important insight that will initiate further observations and theory.”
Senior co-author Dr Farzana Meru, Reader, Department of Physics, University of Warwick concluded: "This work gives observers a new practical toolkit for connecting what we see in dust rings directly to the masses of the planets creating them. What excites me most is the timing. With ALMA delivering increasingly detailed disk images, and future facilities on the horizon, there has never been a better moment to develop these methods.
“Combining our dust-based diagnostics with gas pressure observations will open up a powerful new window onto the hidden planets shaping these disks and the diverse planetary systems they will go on to form."
ENDS
Notes to Editors
The paper "Reading between the Rings: Observed Dust Ring Properties as Probes of Planet Masses" is published in The Astrophysical Journal. DOI: 10.3847/1538-4357/ae6272
Simulation - Simulation of a planet embedded in a protoplanetary disc, causing disc material to pile up in a ring exterior to its orbit – Credit: Amena Faruqi / University of Warwick
GIF- Simulation images showing how tripling the planet mass changes the position of the dust ring. The ring position can be used to determine the mass of the planet causing it. – Credit: Amena Faruqi / University of Warwick
Image - Known as the Disk Substructures at High Angular Resolution Project (DSHARP), this “Large Program” of ALMA has yielded stunning, high-resolution images of 20 nearby protoplanetary disks and given astronomers new insights into the variety of features they contain and the speed with which planets can emerge. Credit: ALMA (ESO/NAOJ/NRAO), S. Andrews et al.; NRAO/AUI/NSF, S. Dagnello
For more information please contact:
Matt Higgs, PhD | Media & Communications Officer (Warwick Press Office)
Email: Matt.Higgs@warwick.ac.uk | Phone: +44(0)7880 175403
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The Astrophysical Journal
Experimental study
Not applicable
Reading between the Rings: Observed Dust Ring Properties as Probes of Planet Masses
28-May-2026