UC Irvine Recasts GJ 3378b as 2.3-Earth-Mass World in Habitable Zone
Updated
Updated · Universe Today · Jul 5
UC Irvine Recasts GJ 3378b as 2.3-Earth-Mass World in Habitable Zone
3 articles · Updated · Universe Today · Jul 5
Summary
A revised UC Irvine-led analysis places GJ 3378b inside its red dwarf star’s habitable zone, after recalculating the nearby rocky exoplanet’s orbit and mass.
The team cut the planet’s estimated mass to 2.3 times Earth’s from an earlier roughly 5-Earth-mass reading and shortened its orbital period to 21 days from 25.
Those changes improve the odds that GJ 3378b is not wrapped in a crushing, dense atmosphere, though its tighter orbit could expose it to stronger stellar radiation that strips air away.
Just 25 light-years from Earth, the planet was detected through radial-velocity measurements with the Habitable-zone Planet Finder, an infrared instrument built to spot tiny wobbles around faint red dwarfs.
Researchers said next-generation observatories including the Giant Magellan Telescope, Extremely Large Telescope and Habitable Worlds Observatory could eventually probe such nearby worlds for biosignatures.
With its mass and orbit now known, is GJ 3378b a true water world or just another barren rock in the habitable zone?
If common minerals can mimic signs of life, how can astronomers ever be sure they've found an alien biosphere?
Could violent stellar flares, once thought deadly, actually be the key to sparking life on newly discovered exoplanets?
GJ 3378b’s New Orbit: A Super-Earth at 2.3 Earth Masses Straddling the Habitable Zone and the Cosmic Shoreline
Overview
In June 2026, scientists published a major update on the exoplanet GJ 3378b, revealing that new analyses had significantly shortened its orbit. This change placed GJ 3378b firmly within the conservative liquid-water habitable zone of its dim host star, meaning that, with a suitable atmosphere, the planet could have surface temperatures that allow liquid water. Because the star is so faint, its habitable zone is located very close to the star itself. This discovery has fundamentally changed how researchers view GJ 3378b’s potential for habitability and highlights the importance of ongoing observations and improved data analysis in exoplanet science.