Astronomers confirmed the youngest planet ever caught still forming around its star

Astronomers have confirmed a planet less than a million years old orbiting the young star Elias 2-24, making it the youngest fully confirmed exoplanet on record and unseating a four-way tie among worlds more than five times as old. The confirmation, published September 16 in The Astrophysical Journal Letters, resolved a decade-old puzzle about a faint point of light that had shown up in telescope data years before anyone could prove it was a planet at all.

The team traced the discovery back to archival images from the W. M. Keck Observatory in Hawaii, not to a new observation, which is part of what makes the confirmation notable: the planet had effectively already been photographed, twice, before anyone recognized what they were looking at.

A Faint Point of Light That Puzzled Astronomers for a Decade

About a decade ago, the Atacama Large Millimeter/submillimeter Array in Chile detected a gap in the dusty disk surrounding the star Elias 2-24, and the European Southern Observatory’s Very Large Telescope later spotted a faint point of light sitting inside that gap. Astronomers debated whether the object could be a planet at all, because existing planet-formation theories predicted that gaps like it should not appear so early, or so far from the star, for a planet to have already formed there.

The object sat roughly 55 times farther from its star than Earth sits from the sun, a distance that made the standard five-million-year formation timeline for a Jupiter-size planet at Jupiter’s own distance seem far too short to explain what the telescopes were seeing. That mismatch is why the point of light spent a decade filed away as an open question rather than a confirmed world: it looked, by the standing theory, more like a measurement artifact than something that could plausibly have finished forming yet.

Archival Keck Images From 2018 and 2020 Solved It

A team led by Andrea Bernardi, a doctoral candidate at the Universidad Diego Portales in Chile, searched the Keck Observatory Archive, a NASA-funded partnership with the NASA Exoplanet Science Institute at Caltech, and found the same faint point of light in observations taken in 2018 and 2020. Stitching those two epochs together let the team track the object’s motion over time and rule out that it was an imaging artifact or a background star.

Bernardi’s search was not limited to Elias 2-24. The team combed through archival Keck data on seven young stars, each surrounded by a debris disk full of dust, gas, and chunks of ice and rock, with visible gaps hinting that planets might be taking shape inside them. A coronagraph at Keck’s NIRC2 instrument blocked the glare of the host star during the original observations, which is what let the much fainter planet register at all.

“The planets should be found within the gaps, since they are carving them,” Bernardi said, adding that the team found Elias 2-24 b in exactly that location. The confirmed planet is roughly as massive as Jupiter, and its star sits about 450 light-years from Earth.

A World Still Younger Than Every Model Expected

Lucas Cieza, a professor at the Instituto de Estudios Astrofisicos in Chile and a co-author of the study, said existing planet-formation models already struggled with the previous record holders. Those were a four-way tie between two planets orbiting the star PDS 70 and two more orbiting WISPIT 2, all more than five million years old. Elias 2-24 b came in at under a million years, an age gap large enough to matter to the physics involved rather than just the record book.

Cieza said Elias 2-24 b shows that even the best available planet-formation models are still missing important processes. Most of the roughly 6,000 confirmed exoplanets found so far are billions of years old and orbit close to their stars, because that combination is easiest to detect using the transit method that dims a star’s light as a planet passes in front of it.

Elias 2-24 b sits about ten times farther from its star than the planet is from its sun in a typical mature system, which is part of why it evaded detection by transit surveys entirely. A wide, dust-shrouded orbit blocks the geometry those surveys depend on, so the planet had to be found by directly imaging a faint point of reflected and emitted light instead, the harder and rarer technique that both Keck and, later, Roman are built around.

The Roman Space Telescope Could Make This Routine

NASA’s Nancy Grace Roman Space Telescope launched August 30, 2026, carrying a coronagraph more powerful than the one used at Keck, built specifically to block starlight and reveal faint planets hiding close to their stars. Bernardi said the confirmation of Elias 2-24 b was only possible by combining data from multiple telescopes years apart, and that newer instruments should make similar detections faster.

Cieza framed the discovery as an opening rather than a conclusion. “This is just the beginning of a new era of discovery,” he said, describing modern technology as finally allowing astronomers to watch planet formation happen in real time, with Roman poised to take planet hunting further. The full findings appear in a study published in The Astrophysical Journal Letters, based on observations detailed by NASA.

This article was produced with the assistance of AI and reviewed by Morning Overview editors prior to publication.

More from Morning Overview