Proxima b
Artist's impression of the exoplanet Proxima Centauri b shown as of a arid (but not completely water-free) rocky Super-Earth.ESO/ Wikipedia

In the Proxima Centauri star system — closest star system from Earth — there is an Earth-sized planet called the Proxima Centauri b and it could be highly habitable, having all the prerequisites necessary to sustain and support life.

The planet is capable of weather, it has vast regions of the surface covered in water, like Earth, and it is in the right distance from its host stars. It could be harbouring life, say astronomers. The planet was first discovered in 2016, notes a report by The study was done by running computer models that are normally used to study the climate on Earth.

New simulations included giving the planet a dynamic, circulating ocean, notes the report. An ocean like this was able to transfer heat from one side Proxima Centauri b to its cold side effectively. In researchers' findings, movement of atmosphere and oceans was combined in such a way that even though the night side of the exoplanet never sees any light from its sun, "there's a band of liquid water that's sustained around the equatorial region," said lead author of the paper Anthony Del Genio, from the NASA Goddard Institute for Space Studies.

"The biggest message from our simulations is that there's a decent chance that the planet would be habitable," he said.

Goldilocks zone
Proxima Centauri b is tidally locked to its starESO/ M. Weiss/CfA

Proxima Centauri is only 4.2 light years away and is a small, red dwarf star. However, in spite of it being so close to Earth, little is known about Proxima Centauri b. It has a mass that is roughly 1.3 times that of Earth and it completes one revolution around its host star every 11 Earth days. The planet can do this and still presumably have liquid water is because the star is a lot cooler in comparison to the Sun.

Also, Del Genio and his team had made some reasonable approximations about the exoplanet, including the composition of its atmosphere and that it had an ocean on its surface. This was done so that they could carry on with their simulations.

Proxima Centauri b is within the star's Goldilocks zone—neither too hot nor too cold for liquid water to exist on the surface. For this star, that zone is extremely close. While this means the years are really short, once every 11 days, being so close to a star could have the entire planet tidally locked to it. Much like how it is only possible to see one side of the Moon from Earth, one side of the planet will be always facing the Star.

The paper describing this new research was published in the journal Astrobiology.