The search for habitable worlds beyond our Solar System is entering an exciting new era. Thousands of exoplanets have already been discovered, and each one offers a different combination of size, atmosphere, orbit, and temperature. At the same time, increasingly powerful ground- and space-based telescopes are bringing scientists closer to the possibility of studying these distant worlds directly.
One particularly interesting target is Gl 514 b, a planet orbiting an M0.5 dwarf star located about 7.62 parsecs, or roughly 25 light-years, from Earth. The planet lies within its star’s habitable zone—the region where conditions could potentially allow liquid water to exist on the surface.
But being in the habitable zone does not automatically mean a planet is habitable. Climate plays a crucial role. A planet can be too cold, too hot, or covered completely by ice. For Gl 514 b, scientists are especially interested because its orbit is highly eccentric, with an eccentricity of 0.45. This means its distance from its star changes significantly during each orbit, potentially causing major changes in the amount of energy it receives.
A Planet With Extreme Seasonal Changes
On Earth, seasons are mainly controlled by the planet’s axial tilt. Gl 514 b presents a more complicated situation. Its elongated orbit can cause large variations in stellar energy, creating potentially extreme seasonal conditions.
When the planet moves closer to its star, it receives much more radiation. Later, as it travels farther away, the incoming energy decreases. These changes could strongly influence surface temperatures, atmospheric conditions, and the amount of ice covering the planet.
To investigate these possibilities, Diaz and their team carried out more than 130,000 climate simulations. They used a one-dimensional seasonal energy balance model called POISE, part of the VPLanet modeling framework.
The researchers varied several important factors, including atmospheric carbon dioxide, orbital eccentricity, planetary tilt, the orientation of the orbit, and the amount and distribution of land on the surface.
The goal was simple but important: Could Gl 514 b maintain conditions suitable for liquid water and perhaps life?
Carbon Dioxide Could Make the Difference
One of the strongest factors controlling the planet’s climate is atmospheric carbon dioxide, or CO₂.
The simulations found that a CO₂ partial pressure between approximately 7.25 and 9.5 bar could allow Gl 514 b to maintain a temperate surface climate.
This is an enormous amount of CO₂ compared with modern Earth. However, such thick carbon dioxide atmospheres are considered physically possible for some rocky planets orbiting M-type or similar low-mass stars.
A thick CO₂ atmosphere can act like a powerful blanket. It traps outgoing heat and prevents the planet from becoming completely frozen. Without enough atmospheric CO₂, Gl 514 b could potentially enter a global snowball state.
Interestingly, the researchers found that an atmosphere containing around 8.375 bar of CO₂ could produce an ice state resembling pre-industrial Earth for a range of planetary tilts between 0° and 40°.
This shows that, under the right conditions, a planet very different from Earth could still develop a surprisingly Earth-like climate.
Ice or No Ice?
The simulations produced several possible climate states.
Gl 514 b was most commonly found in either an ice-free state or a snowball state, in which the surface becomes globally frozen. Only about 1.27% of the simulations produced stable polar ice caps or an ice belt.
This number needs to be interpreted carefully. It does not mean there is a 1.27% chance that Gl 514 b actually has polar ice. It only represents the percentage of simulations that produced partial ice coverage within the particular range of parameters explored by the researchers.
Nevertheless, the result is important because different ice conditions could produce different signals when the planet is eventually observed by future telescopes.
For example, a world with large polar ice caps could reflect light differently from an ice-free planet or a completely frozen world.
Eccentricity Has a Powerful Effect
One of the most striking discoveries from the simulations was the strong influence of orbital eccentricity.
With a fixed atmospheric CO₂ level of about 8.375 bar, the researchers explored eccentricities ranging from 0.45 to 0.62.
The results showed a dramatic difference. Lower eccentricity cases tended toward snowball conditions, while higher eccentricity cases could become extremely hot and approach a runaway greenhouse state.
A runaway greenhouse occurs when a planet becomes so warm that increasing water vapor in the atmosphere causes even more heating, potentially making surface conditions extremely hostile to life.
This demonstrates how sensitive Gl 514 b could be to the exact shape of its orbit.
Does the Amount of Land Matter?
The amount of land on the planet also affected its climate.
The simulations showed that increasing the land fraction generally made the planet colder. However, increasing atmospheric CO₂ could overcome this cooling effect.
The distribution of land was less important. Moving land around the planet did not dramatically change the climate unless large amounts of land were concentrated specifically near the equator or the poles.
The researchers also examined the heat capacity of land and water. Water can store large amounts of heat, helping to reduce extreme temperature changes. This makes oceans an important climate stabilizer, especially on a planet experiencing strong seasonal variations.
The study found that reasonable changes in these heat capacities did not completely transform the planet’s overall climate state, providing some confidence in the results.
Could Gl 514 b Be Earth-Like?
The answer is surprisingly encouraging—but still uncertain.
Some of the simulated conditions produced average surface temperatures close to those of pre-industrial Earth. This means Gl 514 b could potentially have a temperate surface with conditions that are, in some respects, Earth-like.
However, scientists emphasize that this does not prove that the planet is habitable.
The climate model has important limitations. It is one-dimensional, meaning it primarily studies changes with latitude rather than building a complete three-dimensional representation of the planet. It also assumes cloud-free conditions and uses simplified descriptions of land distribution.
Furthermore, although the model accounts for several atmospheric gases, CO₂ is the main atmospheric variable that researchers can change in the simulations.
Real planetary climates are much more complicated. Clouds, atmospheric circulation, oceans, chemistry, volcanic activity, and interactions between the atmosphere and surface can all influence habitability.
Tides Could Change the Story
Another important uncertainty is the planet’s long-term evolution.
Because Gl 514 b orbits relatively close to its star, gravitational interactions could gradually change its rotation, axial tilt, orbital eccentricity, and other properties. These tidal effects may influence how long a day lasts and how heat is distributed around the planet.
The planet’s rotation could eventually become locked into a resonance with its orbit, particularly because of its relatively high eccentricity. Such changes could significantly affect its climate.
Future studies will therefore need to investigate not only what Gl 514 b’s climate could look like today, but also how that climate might evolve over millions or billions of years.
A Snowball World May Not Be Lifeless
Even if Gl 514 b is completely covered in surface ice, that does not necessarily mean life would be impossible.
A frozen surface could potentially hide liquid water beneath the ice. Internal heat from the planet could maintain subsurface reservoirs of water, creating environments where microbial life might survive.
This expands the idea of habitability beyond the simple question of whether liquid water exists directly on the surface.
A Promising Target for Future Telescopes
The study ultimately presents Gl 514 b as a fascinating and potentially habitable world, but not a confirmed second Earth.
Its climate could range from a frozen snowball to an ice-free temperate planet, depending on factors such as atmospheric CO₂, orbital eccentricity, planetary tilt, and land fraction.
The most promising simulations suggest that a thick CO₂ atmosphere—roughly 7.25–9.5 bar—could support a temperate surface.
Perhaps most importantly, the research provides scientists with predictions that future telescopes can test.
Upcoming and next-generation ground- and space-based observatories may eventually be capable of directly studying planets like Gl 514 b. At the level of a single planetary pixel, an ice-covered world, an ice-free world, and a planet with polar caps could produce noticeably different observational signals.
For now, Gl 514 b remains a candidate rather than a confirmed habitable world. But its location, orbital characteristics, and possible climate states make it an especially valuable target.
The study also highlights why understanding an exoplanet’s climate is just as important as discovering the planet itself. Finding a world in the habitable zone is only the beginning. The real question is whether its atmosphere, surface, orbit, and climate can create an environment where water—and perhaps life—can survive.
Gl 514 b may eventually help scientists answer that question.
Reference: Héctor E. Delgado Díaz, Rory Barnes, Russell Deitrick, Mario Damasso, Nathaniel Brown, "Climates of Gl 514 b", Arxiv, 2026. https://arxiv.org/abs/2608.12457
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