Just 4.2 light-years from Earth, an exoplanet orbiting a star in the habitable zone may have a large ocean that increases its chances of supporting life. Proxima b, which has a mass of about 1.3 times that of Earth and orbits a red dwarf star that is about the same age as our Sun, has raised many questions about the conditions on its surface since it was discovered.
However, studies in recent years have increased and disappointed expectations about its habitability. Proxima b may now be capable of supporting life once again, thanks to a recent study that suggests that, under the right circumstances, the exoplanet could support liquid water.
According to Anthony Del Genio, a planetary scientist at NASA's Goddard Institute for Space Studies, "the main message from our simulations is that there is a reasonable chance that the planet is habitable."
The study, which has just been published in the journal Astrobiology, aims to be the first to simulate the climate of Proxima b with a dynamic ocean. The planet is believed to be tidally locked to its star, Proxima Centauri, creating a perpetual "day side" and "night side."
While the water on the dark side freezes, the opposite side doesn’t always do so.
The authors of the current study write: “Climate models with static seas show that Proxima b could host a modest surface ocean on the dayside, despite its weak dynamic (moving) ocean, sometimes even extending to parts of the nightside. The simulations showed that “with a dynamic ocean, a hypothetical ocean-covered Proxima Centauri b could have a habitable climate with a broad region of open ocean extending to the nightside at low latitudes” and that “Proxima Centauri b has an atmosphere similar to that of modern Earth.”
The size of the liquid zones can vary depending on atmospheric greenhouse gas concentrations and salt levels, both of which the researchers modeled. The team found that the exoplanet almost always had a liquid ocean in more than a dozen simulations. But wait until they dive in.
“We find that an ocean-covered Proxima b could have a much larger area of surface liquid water, but at much colder temperatures than previously suggested,” the researchers said. This is due to heat transfer from the ocean and/or a salinity-induced freezing point drop.
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