The planets in our solar system once formed in the rotating disk of dust and gas around the young sun. Now astronomers have discovered the early analogue of such a multiplanetary nursery around a star around 430 light-years away. The protoplanetary disk of the young star WISPIT 2, which is only five million years old, contains at least two young gas giants, as new images from the Very Large Telescope in Chile now show. WISPIT 2 is only the second star around which more than one young planet has been detected. In addition, other dust rings and gaps suggest that other young planets are hidden in this system.
Astronomers have already discovered more than 6,000 exoplanets, as well as hundreds of protoplanetary disks – the rotating disks of gas and dust in which new planets are formed. According to popular belief, the Earth and all other planets in the solar system once formed in the protoplanetary disk of the young sun. Observing other planetary systems in their early stages can therefore provide valuable information about the past of our own system. But spotting young planets still embedded in their dust disks is not easy. Conspicuous gaps, spirals or other dust formations sometimes reveal that a planet must be hidden in the protoplanetary disk. However, confirming this and directly imaging the young planets is a challenge. “To do this, you have to be able to clearly separate the thermal emission of the planet from the scattered light of the surrounding disk,” explain Chloe Lawlor from the University of Galway and her colleagues.
Protoplanetary disks with several growing planets are even rarer and harder to find. They come closest to the assumed early stage of our solar system, but so far only one case of such a multiplanetary nursery has been known: the young star PDS 70, around 370 light-years away, shows the bright spots of light of two young gas giants in the gap in its protoplanetary dust cloud.
Another young gas giant around WISPIT 2
Now astronomers working with Lawlor have managed to find a second system with several growing planets. It surrounds the young star WISPIT 2, which is around 430 light-years away. The sun-like star is a maximum of five million years old and is still surrounded by a dense, large dust disk in which several gaps can be seen. In 2025, astronomers using the European Southern Observatory’s Very Large Telescope (VLT) in Chile discovered the point of light from a young exoplanet in the widest of these gaps. The planet, named WISPIT 2b, is around 4.9 Jupiter masses and is therefore a growing gas giant. It is around 60 times as far away from its star as the Earth is from the Sun. But the structure of WISPIT 2’s protoplanetary disk already suggested that there could be more hidden within it. “The presence of up to four rings with gaps between them raised speculation that this could be a multi-planet system in the formation phase,” Lawlor and her team explain.
That’s why they took another closer look at the young star and its dust disk. To do this, they used the SPHERE infrared spectrograph and the GRAVITY+ instrument on the Very Large Telescope. The latter uses the combined images of all four large telescopes of the VLT and therefore provides particularly high-resolution spectral data. The new observation data revealed that there is actually another young planet around WISPIT 2. This young planet, named WISPIT 2c, orbits further inward than WISPIT 2b and has also created a gap in the dust disk. With an estimated eight to twelve Jupiter masses, this newly discovered gas giant is around twice as large as its neighbor. Astronomers around the young star WISPIT 2 have discovered only the second protoplanetary disk with more than one planet after PDS 70.
(Video: European Southern Observatory (ESO))
Insight into the past of the solar system
“WISPIT 2 offers us the best insight yet into our own past,” explains Lawlor. Because you can now use it to investigate the formation of a young planetary system. “The confirmation of two planets in the young WISPIT-2 system also provides us with a valuable comparative case,” write the astronomers. The similarities and differences between WISPIT 2 and PDS 70 now also make it possible to distinguish individual from possibly universal characteristics of such growing planetary systems. The images show that the young gas giants in both systems orbit at similar distances from their stars and that they have already cleared their orbit in the disk of matter, as the team reports. The gaps result from the growth of the planets: As they orbit the star, the young planets attract dust and gas from their surroundings and thus steadily increase in mass. At the same time, the disk thins out within reach of its attractive force and a gap is created.
In addition to the newly discovered second planet of WISPIT 2, other striking gaps and rings in the protoplanetary disk are also interesting. “These structures suggest that additional planets are currently forming there, which we will detect in the future,” says Lawlor. According to their observations, there is at least one other, smaller gap in the outer part of the WISPIT-2 disk. “We suspect that a third planet is clearing this gap,” said the astronomer. “Due to the narrower width and depth of the gap, it could potentially be a Saturn-mass object.” The team is already planning follow-up observations to try to detect this third young planet.
Source: Chloe Lawlor (University of Galway, Ireland) et al., The Astrophysical Journal Letters, doi: 10.3847/2041-8213/ae4b3b