Astronomers Confirm the Youngest Planet Ever Found, and It Breaks the Formation Rules

Andrea Bernardi wasn't running a new telescope when he found it. He was digging through Keck Observatory images that had sat in an archive since 2018, looking for anything the first pass might have missed. In the gap of a dust ring circling a faint young star 450 light-years away, he found a planet nobody had confirmed before: Elias 2-24 b, a world roughly the mass of Jupiter, born less than a million years ago.

That makes it the youngest planet ever directly confirmed, and by a wide margin. The four planets that held the record before it, two orbiting the star PDS 70 and two orbiting WISPIT 2, were already estimated at more than 5 million years old when astronomers spotted them. Elias 2-24 b is a fifth that age at most, and it sits much farther from its star than any of them did.

A planet that shouldn't have had time

The leading theory of how giant planets form, called core accretion, has dust grains sticking together into pebbles, pebbles into boulders, and boulders eventually into a solid core heavy enough to pull in gas from the surrounding disk. At Jupiter's distance from a star, that process is estimated to take roughly 5 million years. Elias 2-24 b sits 55 times farther from its star than Earth sits from the sun, in a region where raw material is thinner and slower to clump. By the standard math, a planet that far out should take even longer to build. It didn't.

How the record fell

The planet turned up because of what was missing from the disk around it. Elias 2-24, the young star it orbits, is ringed by gas, dust, and small grains of ice and rock, the raw material of planet formation. Bernardi's team spotted a gap cut into that ring, the kind of feature a growing planet leaves as it clears a lane through the debris around it. "The planets should be found within the gaps, since they are carving them," Bernardi said. "And that's exactly where we found Elias 2-24 b."

Confirming it took three observatories working together: coronagraph images from Keck taken in 2018 and 2020, gap-mapping from the Atacama Large Millimeter/submillimeter Array, and an early faint detection from the European Southern Observatory's Very Large Telescope. John O'Meara, chief scientist at the W. M. Keck Observatory, said the underlying data had simply waited for the right tools to read it. "Astronomical data can have a remarkably long shelf life," he said. "The observations existed for years, but new techniques, improved models, and a fresh look at the data revealed something extraordinary."

The catch

Not everyone on the team is calling the case fully closed. Alice Zurlo, a co-author on the study and professor at Universidad Diego Portales who first flagged the star back in 2018, said the planet sits right at the edge of what current instruments can measure, and that theoretical models "still struggle to reliably predict its mass, entropy, and, consequently, its expected luminosity." The team is planning follow-up spectroscopy to pin down the planet's mass directly rather than relying on brightness alone, which is the more indirect method used so far.

“In a way, we're observing a much younger version of a planetary system like our own.”

Why it matters beyond one star

The find adds to a pattern moving fast in one direction: the record for youngest confirmed planet has now fallen twice in about a year, each time pushing the earliest known stage of giant-planet formation further back than modelers expected. Cieza, who worked on both this paper and research into the previous record holders, said the models built to explain those planets already came up short. "Our planet-formation models already struggled to explain the previous record holders," he said. "Elias 2-24 b shows us that even our best planet-formation models are still missing some important processes."

NASA's Nancy Grace Roman Space Telescope, which began operating August 30, 2026, is expected to scan wider patches of sky for disks with similar gaps, which could eventually turn Elias 2-24 b from an outlier into the first known member of a class. For now it stands alone: a single, roughly one-million-year-old data point that the leading theory of how planets like Jupiter form cannot yet fully explain.