Over the past few decades, astronomers have discovered thousands of exoplanet systems around mature stars, revealing a wide variety in the structure of these systems. To understand why planetary systems can look so different, it is essential to study how planets form in the disks of gas and dust surrounding young stars.
A recent study by an international team used the Very Large Telescope (VLT) in Chile to image a young planet forming around a nearby star directly. This planet, named WISPIT 2b, is approximately 5 million years old and is likely a gas giant, similar in size to Jupiter.
WISPIT 2b sits in a gap within the star’s disk and moves along with its host star, confirming it’s part of the system. These observations are part of a larger project studying how gas giants form and evolve when they orbit far from their stars.
Dr Christian Ginski, lecturer at the School of Natural Sciences, University of Galway, and second author of the study, said: “We used these really short snapshot observations of many young stars, only a few minutes per object, to determine if we could see a little dot of light next to them that is caused by a planet. However, in the case of this star, we instead detected a wholly unexpected and stunning multi-ringed dust disk.
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“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.”
WISPIT 2b is the first clearly confirmed planet found inside a disk with multiple rings around a young star. That makes it a perfect place to study how planets interact with the disks they form in, and how they change over time.
Astronomers spotted the planet using near-infrared light, similar to what night-vision goggles see. That’s because WISPIT 2b is still young, hot, and glowing from its recent birth.
WISPIT 2b was captured in stunning detail by astronomers from Leiden University and the University of Galway. They confirmed it’s orbiting its star and sits inside a gap in the star’s disk, a clear sign it’s shaping its surroundings.
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A team from the University of Arizona also spotted the planet in visible light using a special instrument. This revealed that WISPIT 2b is still gathering gas, actively building its atmosphere as it grows.
The discovery was made during a five-year international research project that explored whether gas giants with wide orbits are more common around young or old stars. WISPIT 2b was an unexpected and exciting find.
Young stars are surrounded by disks full of dust and gas, planet nurseries. These disks often exhibit dramatic features, such as rings and spirals, which scientists believe are formed by the presence of planets. The disk around WISPIT 2b is enormous, stretching 380 times the distance between Earth and the Sun.
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Dr Ginski added, “Capturing an image of these forming planets has proven extremely challenging, and it gives us a real chance to understand why the many thousands of older exoplanet systems out there look so diverse and so different from our own solar system. I think many of our colleagues who study planet formation will take a close look at this system in the years to come.”
The study was led by an early-career PhD student, Richelle van Capelleveen from Leiden University, and co-led by a graduate student team at the University of Galway.
The research findings were co-authored by Dr. Ginski and three physics graduate students who are specialising in Astrophysics at the University of Galway.
A companion study by the University of Arizona, led by Professor Laird Close, was triggered based on the information shared about the new disk by the University of Galway and Leiden University team.
Richelle van Capelleveen said, “Discovering this planet was an amazing experience; we were incredibly lucky. WISPIT 2, a young version of our Sun, is located in a little-studied group of young stars, and we did not expect to find such a spectacular system. This system will likely be a benchmark for years to come.”
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Dr Ginski said, “We were so fortunate to have these incredible young researchers on the case. This is the next generation of astrophysicists who, I am sure, will make more breakthrough discoveries in the years to come.”
Chloe Lawlor, PhD student in Physics with a specialisation in Astrophysics at the University of Galway, said: “I feel incredibly fortunate to be involved in such an exciting and potentially career-defining discovery. WISPIT 2b, with its position within its birth disk, is a beautiful example of a planet that can be used to explore current planet formation models. I am certain this will become a landmark paper, owing particularly to the work of Richelle van Capelleveen and her exceptional team.”
Jake Byrne, MSc student in Physics with a specialisation in Astrophysics at the University of Galway, said: “The planet is a remarkable discovery. I could hardly believe it was a real detection when Dr Ginski first showed me the image. It’s a big one – that’s sure to spark discussion within the research community and advance our understanding of planet formation. Contributing to something this impactful, and doing so alongside international collaborators, is exactly the kind of opportunity early-career researchers like Chloe, Dan, and I dream of.”
Dan McLachlan, MSc student in Physics with a specialisation in Astrophysics at the University of Galway, said: “In my experience so far working in astronomy, sometimes you can get so focused on a small task and you forget about the big picture, and when you zoom out and take in the magnitude of what you are working on, it shocks you.”
“This was one such project (an exoplanet direct detection!), and it was such a mind-blowing thing to be a part of. I feel so well treated by the University of Galway Physics department and especially my supervisor, Dr Christian Ginski, for providing me with the opportunity to be part of such an exciting project.”
Journal Reference:
- Discovery of planet WISPIT 2b in formation and captured in infrared light using ESO-VLT in a research project led by Leiden University and University of Galway. The Astrophysical Journal Letters. DOI: 10.3847/2041-8213/adf721
- Detection of WISPIT 2b in visible light led by the University of Arizona. The Astrophysical Journal Letters. DOI: 10.3847/2041-8213/adf7a5
