Exoplanet GJ 3378b emerges as a better candidate to host life than previously expected
- By Kumail Shah -
- Jul 02, 2026
Astronomers using the Hobby-Eberly Telescope at McDonald Observatory have found that the nearby exoplanet GJ 3378b is much more Earth-like than previously thought. Situated only 25 light-years away in the Camelopardalis constellation, this rocky planet orbits a red dwarf star within its habitable zone, suggesting it could support liquid water.
“Our mantra is ‘follow the water,'” stated Paul Robertson, an astronomer at the University of California, Irvine, and lead author of the study recently published in The Astrophysical Journal. He emphasized that water is essential for life, making it a key focus for researchers exploring habitable planets.
The planet’s host star is a red dwarf, smaller, dimmer, and cooler than our sun. Michael Endl, an astronomer at the University of Texas at Austin and co-author of the study, noted that red dwarfs comprise about 70 percent of stars in the Milky Way, making them key in the search for extraterrestrial life.
Because these stars are faint, detecting small, Earth-like planets around them requires extreme precision. The team used the infrared-optimized Habitable-zone Planet Finder to measure the star’s subtle gravitational wobble, allowing them to determine the planet’s specific properties.
This analysis led to a significant revision of the planet’s size: initially thought to be five times Earth’s mass in 2024, the planet is now measured at only 2.3 times Earth’s mass. This correction reclassifies the planet as a rocky “super-Earth,” rather than a massive world with a dense atmosphere that would hinder surface life.
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Researchers have revised the planet’s orbit from 25 days to 21 days. Since red dwarfs emit less heat, this closer orbit is necessary to maintain temperatures suitable for liquid water.
Nevertheless, scientists warn that this near orbit could expose the planet to intense stellar radiation, risking the loss of its atmosphere. Updated data on GJ 3378b will inform upcoming advanced observatories, like the Giant Magellan Telescope, which aim to directly image these nearby worlds and seek definitive signs of life.