Astronomers have confirmed Elias 2-24 b, a world less than a million years old, as the youngest known planet. Identified using archival data from NASA-funded facilities, the Jupiter-mass exoplanet orbits a star 450 light-years away, challenging current planet-formation theories that struggle to explain rapid planetary growth.
A newly confirmed exoplanet resting in its stellar cradle has changed the timeline for planetary evolution. Known as Elias 2-24 b, the world is less than a million years old and remains enveloped in the very disk of dust and gas from which it coalesced, offering scientists a look at a planetary system in its infancy.
Archival Data Unlocks the Elias 2-24 System at Keck Observatory
The breakthrough came after a research team spearheaded by Andrea Bernardi, a doctoral candidate at the Universidad Diego Portales in Chile, re-examined archived observations of seven young stars. The team utilized data from the coronagraph at the W. M. Keck Observatory in Hawaii, an institution that partners with NASA under a cooperative agreement.
By deploying a coronagraph to block the blinding glare of the host star, the researchers searched the surrounding debris disks—regions chock-full of dust, gas, ice, and rock—for hidden companions. Because forming planets carve out distinct pathways as they gather matter, researchers look directly inside those clearings. “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.
Defying Established Planet-Formation Models
The discovery forces a significant rethink of astrophysical theory. Previous record holders for the youngest known planet—a four-way tie involving worlds around the stars PDS 70 and WISPIT 2—are all more than 5 million years old. Elias 2-24 b leaves those benchmarks behind while sitting roughly 55 times farther from its star than Earth is from the Sun.
“Our planet-formation models already struggled to explain the previous record holders for the youngest known planet — a four-way tie between two planets orbiting the star PDS 70 and two planets orbiting the star WISPIT 2 — which are all more than 5 million years old.”
Lucas Cieza, Instituto de Estudios Astrofísicos in Chile
Standard theoretical frameworks dictate that forging a giant, Jupiter-scale planet at such a vast distance should require far more time. Elias 2-24 b’s arrival indicates that missing mechanisms remain absent from our best scientific equations.
“Elias 2-24 b shows us that even our best planet-formation models are still missing some important processes.”
Lucas Cieza, Instituto de Estudios Astrofísicos in Chile
Resolving a Decade-Long Debate With Multiple Telescopes
The confirmation puts to rest a scientific debate that began roughly ten years ago. Initial clues emerged when observations from the Atacama Large Millimeter/submillimeter Array in Chile revealed a conspicuous gap in the dusty disk encircling Elias 2-24. Shortly after, the European Southern Observatory’s Very Large Telescope detected a faint point of light inside that structural opening.
While researchers debated whether the luminescence indicated an actual planet or merely an imaging artifact, Bernardi’s group dug deeper into the Keck Observatory Archive—a collaborative repository hosted by the NASA Exoplanet Science Institute at Caltech/IPAC. By pulling observations captured in 2018 and 2020, the team tracked the object’s proper motion over time, confirming that it behaved more like a planet than a background interloper or optical defect.
Opening a Window on Cosmic Evolution
Observing infant exoplanets remains exceptionally difficult because the dense clouds of birth material typically obscure them from view. Most of the roughly 6,000 confirmed exoplanets cataloged to date have been detected via transits, which require a world to pass directly across the face of its host star relative to Earth’s perspective.
Because transits fail when objects sit buried deep within natal dust or orbit far from their suns, instruments like Keck’s coronagraph are vital. Researchers note that upcoming hardware, such as the recently launched Nancy Grace Roman Space Telescope, will push detection limits even further, allowing astronomers to spot objects and uncover more hidden members of the galaxy’s youngest generations.
