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Astronomers Confirm Youngest Exoplanet Yet
Confirmed
In Short: Astronomers have confirmed Elias 2-24b, an exoplanet less than 1 million years old, as the youngest ever detected.
Astronomers have confirmed Elias 2-24b, an exoplanet less than 1 million years old, as the youngest ever detected. The discovery was made using observations from the Keck Observatory in Hawaii.
The new exoplanet, located about 450 light-years from Earth, is still growing within the disk of gas and dust surrounding its young host star. This makes it significantly younger than other directly imaged protoplanets, which are roughly 5 million years old.
Professor Lucas Cieza, an astronomer at the Instituto de Estudios Astrofísicos in Chile, noted, “Our planet-formation models already struggled to explain the previous record holders for the youngest known planet, which are all more than 5 million years old.”
The confirmation of Elias 2-24b has important implications for understanding planet formation timescales and the origin of gaps observed in very young disks. The exoplanet orbits its star at around 54.9 AU, well beyond Pluto’s orbit in our solar system.
Measuring the orbit of Elias 2-24b will allow astronomers to directly weigh the planet and its companion star, providing crucial insight into the early stages of planetary formation.
The discovery challenges current theories about how quickly giant planets can form. The exoplanet’s age and location suggest that it is still gaining mass from the protoplanetary disk surrounding its star.
The bright point in the image captured by the Keck Observatory on June 21, 2018, is evidence of a forming world, but its exact mass remains uncertain without assumptions about its atmosphere and growth.
This new finding adds to the growing body of evidence that directly imaged young planets orbit stars around 5 million years old, with Elias 2-24b being a significant outlier.
The discovery of Elias 2-24b is a testament to the ongoing advancements in observational astronomy and the ability to detect and study exoplanets at various stages of formation.
The confirmation of Elias 2-24b as the youngest exoplanet yet discovered marks a significant milestone in our understanding of how planets form and evolve.
What this adds
The exact mass of Elias 2-24b remains uncertain without assumptions about its atmosphere and growth.
What's confirmed
- “Our planet-formation models already struggled to explain the previous record holders for the youngest known planet — a four-way tie between two planets orbiting the star PDS 70 and two planets orbiting the star WISPIT 2 — which are all more than 5 million years old,” said Professor Lucas Cieza, an astronomer at the Instituto de Estudios Astrofísicos in Chile.
What's still developing
- Image credit: Bernardi et al., doi: 10.3847/2041-8213/ae9bb6.
- Astronomers had spotted clues there before, but a new analysis of observations from the W.
- Keck Observatory in Hawaii found the object in images taken nearly two years apart.
- But a new paper available in The Astrophysical Journal Letters by a research team led by Andrea Bernardi of Diego Portales University in Chile describes a new paper that definitely takes the prize as the youngest exoplanet we’ve yet found.
- With all the additional context, it became clear that there was indeed an exoplanet orbiting Elias 2-24 at around 54.9 AU - well beyond Pluto’s orbit in our own solar system, but precisely in the middle of the 30-AU-wide gap ALMA had found.
- Most exoplanets we find have been around a long time.
- The best we’ve been able to do so far is to find a planet that had successfully carved out a space in a relatively mature disk, such as the 5.4 million year old exoplanet(s) PDS 70 b/c.
- Using the WEAVE Large-IFU instrument on the William Herschel Telescope in Spain, the astronomers observed the 3I/ATLAS’ plasma tail on November 30 and December 2, 2025, after it passed closest to the Sun.