Plate Nº 52 · recorded October 13, 2026
Space & AstronomyReported finding
ALMA captures first direct image of gas swirling around a forming planet
ALMA has produced the first direct image of gas swirling around a forming gas giant, capturing 5-Jupiter-mass WISPIT 2b mid-accretion 430 light-years from Earth.
By Marcus Bennett3 min read695 words
In brief
- ALMA observed WISPIT 2b in September 2025, with follow-ups in November 2025 and March 2026.
- WISPIT 2b has 5 times Jupiter's mass and sits 57 astronomical units from its host stars, almost twice Neptune's solar distance.
- The WISPIT 2 system lies 430 light-years from Earth, while the previously imaged PDS 70 system lies 370 light-years away.
- Analysis led by Myriam Benisty (MPIA) on an ALMA proposal from Stefano Facchini (University of Milan); two papers posted to arXiv in 2026.
- ALMA's 66 dishes on the Chajnantor Plateau in Chile combine interferometrically to act as a single dish up to 16 km across.
ALMA has produced the first clear image of gas swirling around a forming gas giant, capturing 5-Jupiter-mass WISPIT 2b mid-accretion 430 light-years from Earth.
In September 2025, the 66-dish Atacama Large Millimeter/submillimeter Array (ALMA) in Chile turned toward WISPIT 2b. Follow-up runs in November 2025 and March 2026 produced images of dust and gas at record resolution for a protoplanetary disk.
The result shows a 5-Jupiter-mass planet carving a gap in its birth disk while pulling in surrounding gas — direct visual proof of planet formation in progress.
The analysis, led by Myriam Benisty of the Max Planck Institute for Astronomy, built on an ALMA proposal from Stefano Facchini of the University of Milan. Two related papers posted to arXiv in 2026.
ALMA combines its antennas in interferometric mode to act as a single dish up to 16 km across. That makes it sharp enough to resolve features the size of Earth's path around the Sun at that distance — equivalent, the team notes, to reading a book from 5 kilometers away.
Why does this image matter for planet formation theory?
For decades, researchers have reconstructed planet formation from simulations and indirect traces. The standard sequence runs dust → pebbles → kilometer-scale planetesimals → rocky cores, with gas-rich regions allowing cores to sweep up envelopes and grow into giants.
Swirls in protoplanetary disks appeared in simulations of disk-planet interactions but had never been pinned to a directly imaged protoplanet. Until now, only the PDS 70 system had yielded a confirmed protoplanet image.
Researchers led by then-MPIA doctoral student Miriam Keppler captured PDS 70b in 2018 using ESO's SPHERE instrument on the Very Large Telescope. PDS 70's planets had already swept most gas out of their immediate orbits, leaving little for ALMA to resolve locally.
What exactly did the team see?
WISPIT 2 changes that picture. The system's first known planet, WISPIT 2b, surfaced in August 2025 from SPHERE and 6.5 m Magellan Clay data; its hydrogen-alpha emission shows the planet still accretes gas. A second planet, WISPIT 2c, followed in March 2026 from VLT/SPHERE and GRAVITY+ work.
In the new ALMA images, WISPIT 2c has carved a clear cavity and WISPIT 2b a narrower gap. Inside that gap, swirling gas structures appear for the first time alongside the planet that produced them.
"We clearly see both planets shaping their environment," Benisty said. "WISPIT 2c has carved a cavity, and WISPIT 2b a gap. Around WISPIT 2b, we find swirls of gas that had been predicted by simulations of disk-planet interactions, but never actually seen before. Now there is an image of them!"
Takeaway: WISPIT 2b is now the only protoplanet observed with its disk, its accretion signature, and the gas actively interacting with it all in one frame.
What does this resolve in the field?
Swirl-like features have surfaced in other protoplanetary disks without any planet detection, splitting opinion. Some researchers attribute them to unseen planets; others point to disk turbulence. WISPIT 2b now supplies the first confirmed pairing of swirls with a directly imaged protoplanet.
"Hopefully, observations like this will teach astronomers to distinguish between disk features that indicate the presence of a protoplanet and features that don't," said Facchini, who led the ALMA proposal.
Takeaway: One calibration point cannot close the debate, but it gives theorists a benchmark for separating planet-driven from turbulence-driven features.
What comes next?
WISPIT 2b sits 57 astronomical units (au) from its host stars — roughly twice Neptune's solar distance, far wider than most known exoplanet orbits. Separately, MPIA doctoral student Cade Bürgy showed the "host star" is a tight spectroscopic binary.
The analysis methods now in hand will translate directly to next-generation instruments: ESO's 39 m Extremely Large Telescope and a planned ALMA antenna upgrade aimed at higher sensitivity. Within roughly a decade, those tools could image gas giants at Jupiter-like orbits — and yield sharper insights into how such planets shape their solar systems.
Takeaway: Today's benchmark image sets the template for the surveys that will resolve gas giants at Sun-like orbital distances.
via Phys.org Space & Astronomy (Source)
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News editor covering regulation, policy and their impact on general science news at SciBeat.
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