Image shows the young star WISPIT 2 surrounded by rings of dust and gas, with the glowing infant planet WISPIT 2b visible inside a cleared gap in the disk. (Laird Close/University of Arizona)
For the first time, astronomers have detected a young planet actively growing inside a cleared gap in a star’s protoplanetary disk — a landmark discovery that confirms long-held theories about how planets shape their early environments.
The finding, led by University of Arizona astronomer Laird Close and Leiden Observatory graduate student Richelle van Capelleveen, identifies a planet called WISPIT 2b forming around a sun-like star about 500 light-years away. Their results were published this week in The Astrophysical Journal Letters.
Why this discovery matters
The backstory:
For decades, astronomers have seen striking ring-and-gap patterns in the disks of dust and gas surrounding young stars. These gaps appeared to be carved out by developing planets, yet direct evidence of a planet inside a disk gap had never been found.
"Dozens of theory papers have been written about these observed disk gaps being caused by protoplanets, but no one’s ever found a definitive one until today," Close said in a statement. "Many have doubted that protoplanets can make these gaps, but now we know that in fact, they can."
Using the MagAO-X extreme adaptive optics system on the Magellan Telescope in Chile, Close’s team detected the faint light of hydrogen gas falling onto WISPIT 2b as it continued to grow. The team also observed a second planet candidate, known as CC1, orbiting closer to the star.
MagAO-X, developed by University of Arizona astronomers, is designed to correct for atmospheric turbulence, giving telescopes sharper resolution and the ability to distinguish faint objects from nearby starlight.
The outer planet, WISPIT 2b, is estimated to be about five times the mass of Jupiter and is orbiting at a distance similar to the outer edge of the Kuiper Belt in our solar system. The inner candidate, CC1, appears to be about nine times Jupiter’s mass.
This browser does not support the Video element.
A planet in a perpendicular orbit around 2 brown dwarfs
Using ESO’s Very Large Telescope (VLT), astronomers have found an exoplanet orbiting a pair of peculiar stars at an angle of 90 degrees. (Credit: ESO/Angelos Tsaousis and Martin Wallnet, Raquel Yumi Shida and Edison Arango, Amy Briggs and Sean Bromilow, Luis Calçada, Cristoph Malin (christophmalin.com), Martin Kornmesser, Daniele Gasparri, VPHAS+ team and Paola Amico, Mariya Lyubenova)
About 4.5 billion years ago, our solar system looked much like the WISPIT-2 system does now — a young star surrounded by a disk of dust and gas, where emerging planets shaped the rings and gaps.
"It’s a bit like what our own Jupiter and Saturn would have looked like when they were 5,000 times younger than they are now," said Gabriel Weible, a University of Arizona graduate student who helped measure the planets’ masses.
Astronomers say that snapshots like this give them rare insights into how planets — and eventually solar systems — form.
What's next:
Van Capelleveen, who co-led a companion study at the University of Galway, said detecting young planets requires catching them at a very narrow window of time before they cool and fade from view.
"To see planets in the fleeting time of their youth, astronomers have to find young disk systems, which are rare," van Capelleveen said. "If the WISPIT-2 system was the age of our solar system and we used the same technology to look at it, we’d see nothing."
Researchers say WISPIT 2b will continue to be monitored in both visible and infrared light as new technology helps astronomers refine their understanding of planet formation.
The Source: This report is based on information from the University of Arizona, Leiden Observatory, and The Astrophysical Journal Letters. Additional material was provided by the European Southern Observatory and NASA.