NASA Confirms Youngest Known Planet: Elias 2-24 b

A team of astronomers has confirmed the existence of Elias 2-24 b, a planet orbiting the young star of the same name some 450 light-years from Earth, as the youngest known planet in the universe. The planet is less than one million years old, roughly as massive as Jupiter, and the discovery rests on archival data from the W. M. Keck Observatory in Hawaii. The study was published September 16 in The Astrophysical Journal Letters, and NASA and Keck Observatory issued statements on the find on September 16 and 17.

The study’s lead author is Andrea Bernardi, a doctoral student at Universidad Diego Portales in Chile. His co-authors include Lucas Cieza, whom NASA lists as a professor at Chile’s Institute of Astrophysical Studies and Keck Observatory lists as a professor at Universidad Diego Portales, along with Alice Zurlo, Garreth Ruane, Valentin Christiaens, Dimitri Mawet, Sebastian Perez, Jonathan P. Williams and others.

Until now, the record for youngest known planet had been shared by four worlds: two planets orbiting the star PDS 70 and two orbiting the star WISPIT 2, all older than five million years.

“Our planet formation models already struggled to explain the previous record holders for youngest known planet, the four tied planets around PDS 70 and the planets around WISPIT 2, all older than five million years,” Cieza said in the NASA statement. “Elias 2-24 b shows us that even our best planet formation models don’t capture every important process.”

A Decade-Old Mystery in the Disk Gap

The discovery resolves a question that had puzzled astronomers for about a decade. The Atacama Large Millimeter/submillimeter Array (ALMA) radio telescope in Chile had revealed a gap in the gas and dust disk around the star Elias 2-24. The European Southern Observatory’s Very Large Telescope (VLT), also in Chile, then detected a faint point of light inside that gap. Under the planet formation models of the time, a Jupiter-sized planet at Jupiter’s distance from its star takes roughly five million years to form, and forming farther out takes even longer. Yet the point of light near Elias 2-24 sat 55 times farther from its star than Earth is from the Sun, and it was already behaving like a planet in formation, a mismatch with what the models predicted.

To find out what it was, Bernardi’s team searched the Keck Observatory archive, a joint project of the observatory and the NASA Exoplanet Science Institute at Caltech/IPAC. The same faint point of light turned up in images from 2018 and 2020, taken with the NIRC2 camera and a coronagraph, an instrument that blocks a star’s own light so that fainter objects nearby can be seen. By combining the images and tracking the point’s motion over those two years, the team established that it behaved like a planet rather than an imaging artifact or a distant background star.

“Planets should be looked for within gaps, since that’s exactly what carves them out. And that’s exactly where we found Elias 2-24 b,” Bernardi said.

Elias 2-24 is one of seven young stars whose archival images the team reviewed, all captured with Keck Observatory’s coronagraph. Each one hosts a disk full of dust, gas and chunks of ice and rock, with structures and gaps hinting that planets are forming inside them. Confirming the discovery also drew on data from the ALMA radio telescope and the VLT.

“We usually hear that telescopes work separately, but this confirmation was only possible by using several telescopes together,” Bernardi said in the NASA statement.

In the Keck Observatory statement, he added:

“This is the youngest planet ever discovered, and because it’s still actively gathering material from its surroundings, we get to observe a stage of planet formation that is rarely seen directly.”

Keck Observatory’s chief scientist, John O’Meara, linked the discovery to the value of old data:

“Astronomical data can have an extremely long shelf life. These observations have existed for years, but new techniques, improved models and a fresh look at the data revealed something unexpected.”

Why Does This Discovery Matter for the Hunt for Planets?

NASA ties the discovery to the Nancy Grace Roman Space Telescope, launched August 30, 2026. That telescope carries an even more powerful coronagraph than the ones used in this study and, according to the NASA statement, should make it easier to find similar planets at their earliest stage of formation, including planets on orbits far closer to their star than Elias 2-24 b, which sits roughly ten times farther from its star than is typical for the exoplanets discovered today.

Most of the roughly 6,000 confirmed exoplanets found to date have turned up through the transit method, watching for the brief dimming of a star as a planet passes in front of it. That method struggles with planets buried deep in dust or orbiting far from their star, which is why the vast majority of known exoplanets are billions of years old and sit close to their stars.

“The galaxy is constantly forming new stars and planets, so there are many of them at every stage of development,” Cieza said. “That means in theory we can see the whole process, but there’s a large gap in what most telescopes can detect. Right now we’re largely blind to these baby planets.”

The study rests on confirming a single object, based on comparing archival images from just two points in time, 2018 and 2020, and on an indirect detection through a coronagraph rather than a direct image of the planet. Finding a gap in the disk and a point of light inside it does not by itself prove how the planet formed; it only shows that something is forming faster, and farther from its star, than current models predict. As the study’s own authors stressed, the discovery points to gaps in planet formation models rather than confirming or overturning any single model of formation.