Astronomers confirm youngest known exoplanet, under a million years old, still forming in its disk

By the Everything Space news desk · 16 Sep 2026 · written from the sources below

Image: Phys.org

Elias 2-24 b upends models of planet formation and offers a rare look at a world caught in the act of being built.

Astronomers have confirmed the existence of the youngest planet found so far, a Jupiter-mass world called Elias 2-24 b that is less than a million years old and still embedded in the disk of gas and dust surrounding its star.

The discovery, detailed in a new paper in The Astrophysical Journal Letters, came from a team that revisited archival images from the Keck Observatory in Hawaii. Researchers scanned data from seven young stars with debris disks, looking for faint planets hiding in gaps within those disks, since such gaps are thought to be carved out by forming worlds.

The host star, Elias 2-24, sits roughly 450 light-years from Earth. A gap in its disk was first spotted about a decade ago using the ALMA array in Chile, and a faint point of light was later detected in that gap by the European Southern Observatory's Very Large Telescope. Astronomers debated whether that point of light was actually a planet, since existing theories suggested a gap that far from the star, at roughly 55 times the Earth-sun distance, formed too early and too far out for a planet to have grown there.

To resolve the puzzle, the team searched the Keck Observatory Archive for the same object in separate observations taken years apart, then tracked its motion over time. That analysis showed the object moved like a planet rather than a stray background star or instrument artifact, confirming Elias 2-24 b's status.

The finding complicates current planet-formation models, which already struggled to explain previously known young planets that were at least five million years old. Researchers say the case shows that models are missing key processes and that more examples of newborn planets are needed to refine them.

The team noted that the confirmation relied on combining data from multiple telescopes over time, and that new instruments such as NASA's Nancy Grace Roman Space Telescope, launched at the end of August, carry more powerful coronagraphs that should make spotting similarly young, faint planets easier in the future, including ones orbiting closer to their stars.

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