Youngest Exoplanet Ever Confirmed Is Barely a Million Years Old
Astronomers have confirmed that exoplanet Elias 2-24b, under a million years old, is the youngest exoplanet ever discovered, challenging existing models of how giant planets form.
A research team led by Andrea Bernardi of Diego Portales University in Chile has confirmed that a faint point of light spotted within a gap in a distant star's debris disk is indeed a planet — and the youngest one ever confirmed, at under a million years old.
A decade-long mystery
Astronomers had noticed a gap in the protoplanetary disk surrounding the star Elias 2-24 for nearly ten years, after the European Southern Observatory's Very Large Telescope detected a dim point of light inside it. Whether that light was a genuine planet, background noise, or an unrelated star remained uncertain. The team resolved the question by comparing the dot's position in coronagraph images taken in 2018 and 2020 at the W.M. Keck Observatory in Hawaii, concluding the object was gravitationally bound to its host star — confirming it as a planet, now named Elias 2-24b.
Growing unusually fast
Located roughly 450 light-years from Earth, Elias 2-24b orbits its star at about 55 times the Earth-Sun distance and has an estimated mass of 1.9 to 4 times that of Jupiter, though its volume is likely smaller. Because its host star is under a million years old, the planet is believed to be similarly young, surpassing the previous record holders — planets orbiting PDS 70 and WISPIT 2, both over 5 million years old.
Forcing a rethink of planet formation
Under the standard "core accretion" model, a Jupiter-mass planet is generally expected to need around 5 million years to form even at a much closer orbital distance. Elias 2-24b, orbiting far more distantly, reached giant-planet status in a fraction of that time, suggesting the model can produce such planets faster than previously thought. Coauthor Lucas Siesa noted that even the best current formation models appear to be missing key processes. Researchers hope NASA's Nancy Grace Roman Space Telescope, launched in August and equipped with an even more sensitive coronagraph, will help uncover more young planets and refine these models further.
