Two Planets Found Forming Around Young Star Offer Glimpse of Solar System’s Past

Astronomers have directly observed two planets forming within the swirling disk of gas and dust surrounding a young star, offering an unprecedented glimpse into the birth of a planetary system akin to our own solar system over four billion years ago.

The star, designated WISPIT 2, resides approximately 437 light-years from Earth and is estimated to be around 5.4 million years old. This makes it a relative infant compared to our sun, which is 4.6 billion years old, according to space.com.

The newly forming planets, designated WISPIT 2b and WISPIT 2c, were detected within a protoplanetary disk – a donut-shaped structure of gas and dust – surrounding WISPIT 2. The discovery, announced Tuesday by the European Southern Observatory (ESO), marks only the second time astronomers have directly observed two planets in the process of formation around a single star. The other system, PDS 70, differs from WISPIT 2 in that it lacks the extensive disk and distinct gaps and rings observed around WISPIT 2, making the latter a particularly valuable laboratory for understanding planetary system development.

“WISPIT 2 is the best look into our own past that we have to date,” said Chloe Lawlor, a PhD student at the University of Galway, Ireland, and lead author of the study published in The Astrophysical Journal Letters. “These structures suggest that more planets are currently forming, which we will eventually detect.”

WISPIT 2b was initially discovered last year, possessing a mass nearly five times that of Jupiter and orbiting its star at a distance of approximately 60 times the Earth-Sun distance. Subsequent observations with the ESO’s Particularly Large Telescope (VLT) and the VLT Interferometer (VLTI) confirmed the existence of a second planet, WISPIT 2c, orbiting closer to the star – at roughly 15 times the Earth-Sun distance – and with about twice the mass of WISPIT 2b, according to Leiden University researchers.

Both planets are actively shaping the protoplanetary disk, gravitationally clearing paths as they orbit the star and accrete material. Researchers have also identified a less pronounced gap in the disk, hinting at the potential formation of a third planet, possibly with a mass similar to Saturn. Lawlor indicated that the Extremely Large Telescope (ELT), currently under construction in Chile, may be able to directly image this potential third planet.

“Critically, our study made leverage 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,” said Guillaume Bourdarot of the Max Planck Institute for Extraterrestrial Physics in Germany, in a statement released by ESO.

Richelle van Capelleveen, a PhD candidate at Leiden University who played a key role in the discovery, emphasized the capabilities of current instruments. “The discovery of this planet-in-the-making demonstrates what our current instruments are capable of,” she said.

Christian Ginski, a researcher at the University of Galway and co-author of the study, added, “WISPIT 2 gives us a critical laboratory not just to observe the formation of a single planet but an entire planetary system.”