Astronomers Confirm Youngest Known Planet, Less Than 1 Million Years Old

By edisonreed // 2026-09-19

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Astronomers have confirmed the youngest known planet yet, a Jupiter-size world less than 1 million years old that orbits a star about 450 light-years from Earth, according to a study published Sept. 16 in The Astrophysical Journal Letters. The planet, designated Elias 2-24 b, remains surrounded by the gas and dust from which it formed, giving researchers a rare view of planet formation still underway [1]. The confirmation was led by Andrea Bernardi, a doctoral candidate at the Universidad Diego Portales in Chile, using observations preserved in NASA-funded archives. The planet sits within a gap in its star's dusty disk, a location consistent with predictions of how giant planets carve pathways through surrounding material [1]. "Our planet-formation models already struggled to explain the previous record holders for the youngest known planet," said Lucas Cieza, a professor at the Instituto de Estudios Astrofísicos in Chile and co-author of the paper, referring to a four-way tie between planets orbiting the stars PDS 70 and WISPIT 2, all more than 5 million years old. "Elias 2-24 b shows us that even our best planet-formation models are still missing some important processes" [1].

Discovery and Method

Researchers examined archived observations of seven young stars collected with the coronagraph at the W. M. Keck Observatory in Hawaii, which operates with NASA through a cooperative agreement, according to the study. The coronagraph blocks much of a star's bright light, making it easier to detect fainter objects such as planets hidden within surrounding debris disks [1]. "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" [1]. The team confirmed the object by searching the Keck Observatory Archive and locating the same faint point of light in observations collected in 2018 and 2020. By combining the observations and tracking how the object moved over time, the researchers determined it behaved like a planet orbiting the star rather than an imaging artifact or a distant background star [1]. Planets orbiting stars beyond the solar system are known as exoplanets. Most of the roughly 6,000 confirmed exoplanets have been found through transits, a method that becomes much harder to use when planets are still buried in dust or orbit far from their stars. As a result, most confirmed worlds are billions of years old and orbit relatively close to their stars, according to the study [1]. Previous research has established that stars form within vast clouds of gas and dust, and that jets carry away angular momentum to allow accretion to continue [2].

Challenge to Planet Formation Theories

Current models suggest that forming a Jupiter-size planet at Jupiter's distance from the Sun, which is just over five times the distance of Earth to the Sun, takes about 5 million years, according to the study. A giant planet much farther out should take even longer. Yet the faint object in the Elias 2-24 system sits about 55 times farther from its star than Earth is from the Sun and is less than 1 million years old [1]. "Our planet-formation models already struggled to explain the previous record holders," Cieza said. "Elias 2-24 b shows us that even our best planet-formation models are still missing some important processes" [1]. The finding challenges leading theories of giant planet formation, which cannot readily explain such rapid formation at great distances from a host star. Scientists currently build planet formation models using theories, computer simulations, and observations of young stars surrounded by disks where forming planets are often too difficult to detect directly. "The galaxy churns out new stars and planets continuously, so there are many in every stage of evolution," Cieza said. "That means we can see the entire process in theory, but there is a large gap in what most telescopes can detect. We are mostly blind to these baby planets right now" [1]. Discoveries such as Elias 2-24 b can provide crucial real-world tests for those models, according to the researchers.

Resolving a Decade-Old Mystery

The confirmation resolves a question astronomers have debated for about 10 years. Earlier observations from the Atacama Large Millimeter/submillimeter Array in Chile revealed a gap in the dusty disk surrounding the young star Elias 2-24. Later, the European Southern Observatory's Very Large Telescope in Chile spotted a faint point of light inside that gap, according to the study [1]. Scientists wondered whether the object could be a planet. Existing planet formation theories suggested a large planet should not have been able to form so quickly, especially at such a great distance from its star, the researchers stated. The new analysis of archival Keck data confirmed the object as a planet [1]. "We usually hear about telescopes working separately, but this confirmation was possible only by using multiple telescopes together," Bernardi said. "Elias 2-24 b is at the limit of what current telescopes can detect, but with new instruments like NASA's Nancy Grace Roman Space Telescope, such detections should become easier" [1]. Because the system is so young, studying it gives astronomers a glimpse of what our own solar system may have looked like billions of years ago, according to the study. Prior research has noted that a new planet orbiting another star, Rho Coronae Borealis, was observed in 1997 by Robert Noyes of the Harvard Smithsonian Astrophysical Observatory and is of the size of Jupiter [3].

Future Observations with Roman Space Telescope

NASA's Nancy Grace Roman Space Telescope launched Aug. 30 carrying an even more advanced coronagraph designed to detect planets that are much harder to see with existing telescopes. Using similar observing methods, Roman could identify planets in tighter orbits, including true Jupiter analogs that are currently hidden by the glare of their stars, according to the study [1]. Elias 2-24 b orbits about 10 times farther from its star than Roman could detect. That added sensitivity could help astronomers discover more planets during their earliest stages of formation and close one of the biggest observational gaps in exoplanet science. "This is just the beginning of a new era of discovery," Cieza said. "It's incredible that with modern technology, we are actually able to see planet formation in action, and Roman will take planet hunting to the next level" [1]. The discovery adds to a field that has expanded rapidly since the Kepler space telescope launched March 6, 2009, to study some 150,000 stars in the constellations Cygnus and Lyra. At that time, there were 374 known exoplanets, discovered over the course of 17 years, according to one account of the mission [4]. The confirmation of Elias 2-24 b continues that expansion.

References

NASA. "Astronomers just found the youngest known planet ever". ScienceDaily. September 17, 2026.
Scientific American Inc. "The Secret Lives of Stars".
Veer Bala Rastogi. "Organic Evolution Evolutionary Biology Rev Updated Ed".
Damien Hutsem. "Astronomy - March 2015 USA".

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