Astronomers Spot the Youngest Known Exoplanet—And It’s Surprisingly Massive

For more than a decade astronomers have been staring at the dusty swirl surrounding a tiny, fledgling star called Elias 2‑24, wondering whether anything substantial was taking shape inside.

That suspicion got a boost when the ALMA array in Chile spotted a neat gap in the disk—a classic sign that something massive might be carving a path. Later, the European Southern Observatory teased a faint glimmer right in the middle of that gap.

At first glance the little point of light seemed impossible. According to the textbooks, a Jupiter‑sized planet needs roughly five million years to grow at the distance where this object sits—about eleven times farther out than Jupiter is from the Sun. Yet the star itself is thought to be younger than a million years. How could such a big world appear so quickly?

A team led by doctoral candidate Andrea Bernardi dug into archival coronagraph images from the W. M. Keck Observatory in Hawaii. By stitching together data collected between 2018 and 2020, they could actually watch the speck move, confirming it wasn’t a background star or an imaging glitch.

The conclusion was hard to ignore: the speck is a planet, now christened Elias 2‑24 b. The researchers estimate its age at less than one million years—making it the youngest exoplanet ever directly observed. Because it still hides behind a thick veil of gas and dust, pinning down its exact mass is tricky, but models suggest it could be anywhere from two to fourteen times the mass of Jupiter.

“Our planet‑formation models already struggled to explain the previous record‑holders—those four‑year‑old planets around PDS 70 and WISPIT 2,” explains co‑author Lucas Cieza of the Instituto de Estudios Astrofísicos. “Elias 2‑24 b shows us that even our best theories are missing something fundamental.”

What makes the find even more tantalizing is the star’s own youth. One study puts Elias 2‑24 at a mere 400,000 years old, another pushes that number down to about 200,000 years. Its high accretion rate tells us the star is still gulping material from its surroundings, and now its planet appears to be doing the same, but at a breakneck pace.

Detecting a newborn giant in such a crowded, glowing environment is a feat of observational gymnastics. “We usually hear about telescopes working solo, but this confirmation was only possible by layering data from ALMA, the VLT, and Keck together,” says Bernardi. “Future instruments, especially the newly launched Nancy Grace Roman Space Telescope, will make this kind of hunt far easier.”

Roman’s coronagraph, the most powerful ever sent to space, can block out a star’s glare well enough to see planets that are a hundred million times fainter. That leap in sensitivity could turn a handful of infant planets into a growing catalog, giving theorists a much richer playground to test and refine their models.

For now, Elias 2‑24 b serves as a natural laboratory—an actual snapshot of planet birth that challenges the status quo. As Cieza puts it, “It’s incredible that with modern technology we can watch planet formation in action. Roman will take that to the next level, and we’re just getting started.”