Astronomers confirm second newborn giant planet in ringed WISPIT 2 system

A young, sunlike star wrapped in concentric rings of dust has yielded a second newborn giant planet, giving astronomers one of their clearest views yet of how planetary systems like our own take shape.

An international team has confirmed that a faint, close-in source in the WISPIT 2 system is a true gas giant planet, not just a knot of disk material. The finding makes WISPIT 2 only the second known star system, after the well-studied PDS 70, where multiple planets have been directly observed while still forming inside their birth disk.

The result, led by Chloe Lawlor of the University of Galway, appears in a paper posted March 23 on the online preprint server arXiv and is accompanied by a news release from the European Southern Observatory, which operates the telescopes used in the discovery.

“WISPIT 2 is the best look into our own past that we have to date,” Lawlor said in the observatory’s statement.

The newly confirmed world, called WISPIT 2c, orbits roughly 15 times farther from its star than Earth does from the sun and is estimated to be 8 to 12 times the mass of Jupiter. It joins WISPIT 2b, a previously discovered gas giant more than 50 astronomical units out, inside a wide gap in the system’s multi-ringed disk.

Together, the two planets and the sculpted bands of dust and gas around them offer an unusually detailed snapshot of a planetary system under construction.

A ringed disk that demanded an explanation

WISPIT 2, also known by its catalog designation TYC 5709-354-1, lies about 437 light-years away in the Scorpius–Centaurus stellar association. The star is around 5 million years old and slightly more massive than the sun, placing it at an age when its surrounding disk is expected to transition from a continuous sheet of material into a more structured landscape shaped by emerging planets.

Images taken with the SPHERE instrument on the European Southern Observatory’s Very Large Telescope (VLT) in Chile revealed a striking set of concentric rings and gaps in scattered light, extending hundreds of astronomical units from the star. Those features resembled the intricate ringed disks around young stars that the Atacama Large Millimeter/submillimeter Array (ALMA) has made famous over the past decade.

“When we saw this multi-ringed disk for the first time, we knew we had to try and see if we could detect a planet within it, so we quickly asked for follow-up observations,” Christian Ginski of the University of Galway, a co-author on the new study, said in earlier coverage of the system.

That effort paid off in 2025, when astronomers using the MagAO-X adaptive optics system on the Magellan telescope in Chile picked up a bright hydrogen emission signal from a young giant planet, WISPIT 2b, embedded in a wide gap about 57 astronomical units from the star. The planet, roughly five times Jupiter’s mass, was seen shining in the H-alpha line, a telltale sign of hot gas falling onto its surface.

The discovery turned WISPIT 2 into one of the best cases linking an observed disk gap to a specific, gap-opening planet.

A suspicious inner source

Those same MagAO-X observations also revealed a second, much closer source, labeled “CC1” for companion candidate, at a projected separation corresponding to about 15 astronomical units. Its nature was unclear. It could have been a second planet, but it could also have been a bright clump in the star’s own disk viewed against the glare of the central star.

Distinguishing between those possibilities required far sharper vision and more detailed information than a single, low-resolution detection could provide.

“The big question was whether this was really a compact object or just part of the disk masquerading as one,” Lawlor said in remarks released by the observatory.

To answer it, Lawlor’s team turned to a combination of instruments at ESO’s Paranal Observatory.

First, they used SPHERE in a polarimetric mode in near-infrared light to pin down the candidate’s location relative to the disk structures seen previously. Then they observed the system with GRAVITY+, a recently upgraded near-infrared interferometer at the Very Large Telescope Interferometer (VLTI) that effectively combines the light from multiple telescopes to achieve milli-arcsecond resolution.

A planetary fingerprint in the spectrum

The GRAVITY+ observations delivered two key pieces of evidence. They showed that the inner source is point-like, consistent with a compact object rather than an extended patch of dust. More importantly, GRAVITY+ produced a medium-resolution spectrum in the K band around 2 microns in wavelength that carries the telltale signature of a hot, giant planet atmosphere.

The spectrum displays prominent absorption features from carbon monoxide molecules at about 2.3 microns, known as CO band heads, and a continuum shape matching theoretical models of a self-luminous gas giant. A dense clump of dust in the disk would be expected to show a very different spectral profile.

Using atmospheric and evolutionary models, the team estimated an effective temperature between 1,500 and 2,600 kelvins and a luminosity roughly 3,000 times fainter than the sun. Those values imply a radius of about one to two times Jupiter’s and a mass in the range of 8 to 12 Jupiter masses, making WISPIT 2c somewhat more massive than its outer sibling.

Astrometric measurements — subtle shifts in the object’s apparent position over time — further supported the planet interpretation. The team ruled out a chance alignment with a distant background star and reported marginal evidence of motion consistent with a bound orbit around WISPIT 2.

“Critically, our study made use of the recent upgrade to GRAVITY+ without which we would not have been able to get such a clear detection of the planet so close to its star,” co-author Guillaume Bourdarot of the Max Planck Institute for Extraterrestrial Physics said in the ESO release.

A second laboratory for planet formation

With two confirmed forming giants embedded in its disk, WISPIT 2 now joins PDS 70 as one of the few systems where astronomers can simultaneously study multiple protoplanets and the structures they carve in their surroundings.

In PDS 70, both known planets orbit within a single, large inner cavity. WISPIT 2’s architecture appears more layered: an inner giant at about 15 astronomical units, an outer giant at nearly 60, and several rings and gaps extending farther out. Millimeter observations with ALMA have revealed a narrow ring of large dust grains at about 144 astronomical units, with WISPIT 2b well interior to that structure.

Those features make WISPIT 2 an important test case for models of how giant planets open gaps and shape disks, and how systems with multiple gas giants might evolve over time.

“WISPIT 2 gives us a critical laboratory not just to observe the formation of a single planet but an entire planetary system,” Ginski said.

Some of the more distant gaps in the disk may hint at additional planets yet to be found. Lawlor said the team suspects a third, Saturn-mass planet is carving a narrower outer gap and could come into view with future telescopes.

Looking ahead to bigger telescopes

The confirmation of WISPIT 2c highlights the role of large, ground-based observatories and advanced adaptive optics in exoplanet science. The work relied on ESO’s VLT and VLTI, the Magellan telescopes operated by a U.S.-led consortium, and ALMA, a partnership of Europe, North America, East Asia and Chile.

It also points toward what astronomers hope to achieve with the next generation of extremely large telescopes, such as ESO’s Extremely Large Telescope under construction in northern Chile.

Future observations of WISPIT 2 with those facilities could tighten the orbits and masses of the known planets, search for lower-mass companions, and directly resolve any disks of material surrounding the planets themselves — regions where moons may eventually form.

For now, WISPIT 2 stands as one of the clearest windows onto a process that shaped Earth’s own neighborhood billions of years ago.

“We can’t go back in time and watch our solar system being born,” Lawlor said. “But by studying systems like WISPIT 2, we can see many of the same steps playing out in front of us.”