Astrophysicist Anthony Del Genio and his colleagues at the Goddard Institute for Space Studies in the United States conducted the first three-dimensional climate simulations of the exoplanet Proxima Centauri b, models similar to those used to study climate change on Earth.
They believe that Proxima would house a larger area of liquid water than previously thought. The temperature of this water could be colder than estimated, because of ocean circulation, temperature differences and the salinity of the water that lowers its freezing point.
The main information that emerges from our simulations is that there is a good chance that the planet is habitable.
— Anthony Del Genio, Goddard Institute
A planet is considered habitable when it is at a distance from its star that allows it to receive enough light to maintain its surface — or part of its surface — above the freezing temperature of water.
As it is very close to her star, it is likely that it always show it the same face because of the gravitational forces, a little like the Moon always shows the same side to the Earth.
In 2016, other computer models had showed to show that the chemical composition of its atmosphere was similar to that of the Earth, and that it had a primitive atmosphere consisting of nitrogen and carbon dioxide.
This latest work shows that the hemisphere of the exoplanet facing its star could be very hot, while a frozen ocean would be in the other hemisphere. Thus, only a circle of hot water could exist.
However, the current simulations, more complete than the previous ones, suggest that a much more dynamic ocean would be there and would be able to efficiently transfer heat from one side to the other of the exoplanet.
“Even if the dark side never sees light, there would still exist a band of liquid water, which would remain around the equatorial region,” says Anthony Del Genio.
The details of this study are published in the journal Astrobiology.