Youngest Confirmed Planet Caught Growing in Its Birth Disk

Astronomers have confirmed Elias 2-24 b, a Jupiter-mass world under one million years old still accreting gas inside a gap in its star’s dusty disk about 450 light-years away.

Today’s Progress

A research team led by doctoral candidate Andrea Bernardi at Universidad Diego Portales in Chile has confirmed the youngest known exoplanet. Named Elias 2-24 b, the Jupiter-mass world is less than one million years old and still gathering material from the gas-and-dust disk around its young host star.

The system lies roughly 450 light-years from Earth in the ρ Ophiuchi star-forming complex. The planet orbits about 55 astronomical units from its star—roughly 5.1 billion miles, or about ten times farther than Jupiter sits from the Sun—inside a gap spanning about 30 astronomical units.

The study, published 16 September 2026 in The Astrophysical Journal Letters, combines archival infrared images from the W. M. Keck Observatory’s NIRC2 vortex coronagraph on Maunakea with data from the Atacama Large Millimeter/submillimeter Array (ALMA) and the European Southern Observatory’s Very Large Telescope. Earlier ALMA maps had shown the gap; faint emission near it raised the possibility of a planet. Keck frames from 2018 and 2020, reanalyzed with improved techniques and models, showed a source whose position and apparent motion match a bound companion rather than background clutter or an artifact.

“The planets should be found within the gaps, since they are carving them,” Bernardi said in a NASA release. “And that’s exactly where we found Elias 2-24 b.”

NASA and Keck report that the object is still actively accreting, placing it in a brief, bright growth phase. The team’s analysis favors the core-accretion pathway—solid bodies building a core that then draws in gas—over pure gravitational collapse of the disk, though the full formation history remains incomplete.

Previous direct-imaging record holders, including planets around PDS 70 and WISPIT 2, are more than about five million years old. Elias 2-24 b pushes confirmed detections much closer to the start of planet assembly.

Why This Matters

Protoplanetary disks show rings and gaps that many astronomers have long attributed to forming planets, yet direct evidence at the earliest ages has been scarce. Catching a giant planet still embedded in its birth disk links a clear gap to a real, growing world and supplies an observational anchor for theories of how systems like our own take shape.

The benefit is knowledge, not hardware or commerce: clearer constraints on how fast giant planets can assemble at wide separations, and a living laboratory for the processes that built the solar system billions of years ago. Co-author Lucas Cieza of Universidad Diego Portales noted that older systems force reconstruction after the fact, while Elias 2-24 lets researchers watch the process while it is underway.

Evidence and Context

Evidence stage is demonstrated for the detection and youth relative to prior imaged planets, and promising-early for the detailed formation pathway. Strengths include multi-facility consistency (Keck, ALMA, VLT), multi-epoch motion consistent with a bound object, and a location that matches gap-carving models. Limits remain: mass is described as roughly Jupiter-class rather than a single precise value; atmospheric, temperature, and refined mass measurements await spectroscopy and further monitoring; orbital motion over longer baselines is still needed. Formation at ~55 au in under a million years strains the slowest core-accretion timelines, so models are incomplete even if the data favor that channel. No substantial harm is associated with the discovery itself.

Primary sources include the peer-reviewed Astrophysical Journal Letters paper (DOI: 10.3847/2041-8213/ae9bb6), NASA’s science feature, and the W. M. Keck Observatory release.

What Made This Possible

Archival longevity mattered. Keck Observatory Chief Scientist John O’Meara observed that older frames gained new value once better reduction methods and models were available. Coronagraphy that suppresses starlight, ALMA’s earlier gap maps, and coordinated international telescope access together made the confirmation possible. Lead authorship from a Chilean doctoral program illustrates how open archives and multi-wavelength collaboration can support doctoral-led research.

Progress Toward Global Goals

The work advances scientific capacity and open knowledge rather than a direct social service outcome. It aligns defensibly with SDG 9 (Industry, Innovation and Infrastructure) through publicly usable observatory archives and international research infrastructure, and with SDG 4 (Quality Education) insofar as doctoral-led, openly reported discovery may support advanced scientific training. No direct adverse social or environmental impact was identified in connection with the discovery.

Building on This Success

The following possibilities were generated with the assistance of AI to explore how this progress might be improved, expanded, or adapted. They are ideas for further investigation, not established findings or recommendations from the people featured in the original reporting.

Targeted spectroscopy and multi-epoch astrometry could tighten mass, temperature, and accretion-rate estimates, turning a single confirmed object into a calibrated benchmark for disk–planet interaction codes. Parallel reanalysis of other ALMA-gapped disks with the same vortex-coronagraph pipeline might test whether Elias 2-24 b is exceptional or the first of a larger early-accretion population. Cross-checks with next-generation space coronagraphs could then search for closer-in analogs that ground-based glare still hides.

How does confirming a still-accreting giant planet under one million years old change tests of core-accretion theory?

Through a science-methods lens, the intervention is multi-epoch direct imaging plus disk modeling; the actors are university-led teams using Keck, ALMA, and VLT archives; the mechanism is placing a growing mass inside a young, narrow gap and comparing brightness and gap width to core-accretion predictions; the obstacle is incomplete mass and atmospheric data plus theoretical tension at wide separations; the measurable test is whether refined dynamical mass and accretion luminosity fall inside core-accretion tracks at ~50 au within ~1 Myr, or require faster pathways.

Through an open-science lens, the same archival frames become a reusable testbed: other groups can re-reduce the public Keck data, vary disk assumptions, and report whether the companion remains preferred over background or artifact explanations—an external reproducibility check independent of the original team.

Three Promising Next Steps

1. Obtain infrared spectroscopy to constrain temperature, composition, and ongoing accretion luminosity against model grids.
2. Extend astrometric monitoring to measure orbital motion and derive a dynamical mass independent of disk kinematics.
3. Apply the same coronagraph-plus-ALMA search uniformly to other sub-million-year disks with narrow gaps to test how common such early giants are.

What Readers Can Watch

• Follow-up papers citing DOI 10.3847/2041-8213/ae9bb6 for mass, atmosphere, or orbital updates on Elias 2-24 b.
• Early exoplanet results from the Nancy Grace Roman Space Telescope coronagraph, noted by the team as a path to closer-in forming planets.
• New ALMA or extreme-adaptive-optics releases on other young gapped disks in Ophiuchus and similar regions.

What Readers Can Do

Readers can follow primary updates from NASA’s feature on the discovery, the W. M. Keck Observatory release, and the peer-reviewed paper via its DOI. Public observatory archives and open journal access remain the main channels for independent scrutiny.