Astronomers have identified an intriguing rocky exoplanet, Gliese 3378b, which is approximately twice the size of Earth. This exoplanet resides within the habitable zone of its parent star, Gliese 3378, located only 25 light-years away from us.
Artist’s concept showing the surface view from Gliese 3378b. Image credit: Nikolai Berman / UC Irvine.
Gliese 3378, also known as GJ 3378, LHS 1805, or TIC 322347050, is a red dwarf star situated 25 light-years away in the northern constellation of Camelopardalis.
The newly discovered exoplanet Gliese 3378b boasts a mass about 2.3 times greater than that of Earth and completes its orbit in just 21.45 days.
This planet exists within the host star’s habitable zone—a “Goldilocks” region where conditions are suitable for liquid water to potentially exist on its surface due to the optimal amount of solar radiation received.
“Approximately 70% of the stars in our galaxy are red dwarfs, making them quite common,” explained Dr. Michael Endl, an astronomer at the University of Texas at Austin. “Gaining insights into the planetary systems surrounding these stars is crucial.”
“This discovery is fascinating,” Dr. Paul Robertson from the University of California, Irvine remarked. “While 25 light-years may seem distant, the Milky Way stretches roughly 100,000 light-years across, making Gliese 3378b one of our closest celestial neighbors.”
In their study of Gliese 3378b, Dr. Endl, Dr. Robertson, and their team utilized the Habitable Zone Planet Detector on the Hobby-Eberly Telescope at McDonald Observatory in Texas, as well as the NEID spectrometer on the WIYN Telescope at Kitt Peak National Observatory in Arizona.
“This super-Earth is in the ideal zone, receiving around 90% of the solar radiation that Earth gets from our Sun,” Dr. Robertson noted.
A lingering mystery remains regarding the atmosphere of Gliese 3378b, specifically whether it has one at all.
This planet lies on what researchers refer to as the edge of the cosmic shoreline, a region around a star where the atmosphere may be stripped away by solar radiation.
For comparison, scientists believe Mars may have once possessed a similar atmosphere to that of Earth, which has since been eroded by solar radiation.
“If Earth were reduced to the size of an apple, its atmosphere would be as thin as the apple’s skin,” Robertson elaborated. “This minimal thickness can still maintain enough surface pressure for liquid water to exist.”
“A suitable atmosphere may also provide breathable air and some protection against the harsh radiation of space.”
The discovery of Gliese 3378b thus adds another candidate to the growing list of potentially habitable exoplanets.
“If a planet in the habitable zone has the right atmospheric conditions, it could warrant further research into biosignatures, liquid water, and other indicators of life that depend on both an atmosphere and suitable heating from its star,” stated Gogod James, a student at the University of California, Irvine.
Details of these findings will be published in the Astrophysical Journal.
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Paul Robertson et al. 2026. Revision of the mass and period of the habitable zone super-Earth GJ 3378b: a planet that spans the cosmic coastline. APJ 1005, 32; doi: 10.3847/1538-4357/ae732b
Source: www.sci.news
