Astronomers have confirmed the discovery of Elias 2-24 b, a Jupiter-mass exoplanet located 450 light-years away that is less than one million years old, making it the youngest known planet outside our solar system. The discovery involved analyzing archive data from the W.M. Keck Observatory, with contributions from Argentinian astrophysicist Lucas Cieza.
Inside the Ophiuchus Star-Forming Region
The newly confirmed exoplanet orbits within the circumstellar disc of gas and dust surrounding its host star, Elias 2-24. According to observations detailed in The Astrophysical Journal Letters, this stellar nursery is situated in the Ophiuchus molecular cloud. Most of the roughly 6,000 confirmed exoplanets discovered to date were detected using the transit method, which relies on measuring the dimming of a star as a planet passes in front of it. However, that technique struggles to spot objects still buried deep within their natal envelopes of dust.
To bypass this obstacle, a research team led by Andrea Bernardi, a doctoral student at Diego Portales University in Chile, analyzed archival observations of seven young stars captured by the Keck Observatory’s coronagraph. This instrumentation blocks the blinding glare of the host star, revealing much fainter signals in the surrounding circumstellar material. By comparing images taken in 2018 and 2020, the team verified that a distinct point of light maintained a proper motion consistent with an orbiting companion.
“The planets should be inside the gaps, because they are the ones that open them. And that is exactly what we found with Elias 2-24 b,” Bernardi stated, as reported by NASA.
Challenging Current Planetary Formation Models
The discovery forces a rethink of how quickly gas giants can coalesce. Those prior benchmarks involved a group of four worlds orbiting two stars, all exceeding five million years of age.
Elias 2-24 b shatters that timeline at under one million years old. Standard theoretical frameworks suggest that a Jupiter-mass planet takes roughly five million years to form at a distance comparable to Jupiter’s orbit around our Sun. Yet Elias 2-24 b orbits its host star at a distance roughly 55 times the separation between Earth and the Sun—an orbital radius nearly ten times wider than Jupiter’s.
“Elías 2-24 b shows us that even our best models of planet formation still do not understand some important processes,” Cieza explained.
Decade-Long Detective Work in Astronomical Archives
The identification of Elias 2-24 b resolves a decade of ambiguity regarding a visible gap in the star’s circumstellar disc. The structural void was initially flagged in data captured by the Atacama Large Millimeter/submillimeter Array (ALMA). Subsequent observations by the Very Large Telescope (VLT) revealed a faint emission source at the exact same coordinates, though researchers initially could not rule out a background star or instrumental artifact.
The multi-telescope convergence—utilizing ALMA, the VLT, and Keck—finally pinned down the signal. Santiago Orcajo, a graduate of the University of La Plata who worked alongside Cieza on earlier phases of circumstellar disc evolution research, contributed to the foundational numerical models that connected these observed disc structures to an actively forming planet.
Looking Ahead with Advanced Coronagraphy
Catching planets during their infancy remains exceptionally rare. As Cieza noted, astronomers are largely blind to newborn worlds because most current instruments cannot peer through the dense dust lanes where planets are born. Researchers hope that future hardware, such as the upcoming Nancy Grace Roman Space Telescope equipped with an advanced coronagraph, will make these detections routine and expose planets in tighter orbits.
By studying Elias 2-24 b today, astrophysicists gain a pristine temporal window into the physical mechanisms that likely shaped our own solar system billions of years ago.
