Nearest exoplanet to the Earth could be ‘very liveable’

An artist’s impression of the view of Proxima Centarui b, a newly discovered Earth-sized planet just four light-years away. It is unclear whether there is intelligent life in the universe, but are looking for more and more of earth-like planets in the habitable zones of their respective stars. (Credit: NASA)

Only a cosmic hop, skip and a jump away, an Earth-size planet in an orbit around the nearest star, our sun, Proxima Centauri.

Since the discovery of the exoplanet, known as Proxima Centauri b in 2016, people have wondered whether it would be capable of sustaining life.

Now, using computer models similar to those used for the study of the climate change on Earth, researchers have found that under a wide range of conditions, Proxima Centauri b can sustain huge areas of liquid water on its surface, may increase the prospects for harboring living organisms. [9 Strange, Scientific Excuses for Why Humans Haven’t Found Aliens Yet]

“The main message of our simulations is that there is a good chance that the planet is habitable,” said Anthony Del Genio, a planetary scientist from the NASA Goddard Institute for Space Studies in New York City. Del Genio is also the principal author of a paper describing the new research, which was published in Sept. 5 in the journal Astrobiology.

Proxima Centauri is a small, cool red dwarf star is only 4.2 light years from the sun. Despite its proximity, scientists still know very little about Proxima Centauri’s planetary companion, in addition to that the mass of at least 1.3 times that of the Earth, and that it is going to be older starevery 11 days. Therefore, Del Genio and his colleagues had to make reasonable estimates about the exo-planet Proxima Centauri b — namely, that it is an atmosphere and an ocean on the surface for their work.

Proxima Centauri b orbits in its star’s habitable zone, which means that it is exactly the right distance to get enough starlight to keep the surface above the freezing temperature of the water. But this zone is very close to the star, a Live Science sister site, reported. It is thus likely that the planet has become tidally locked due to gravitational forces. This means that the same side of Proxima Centauri b always faces its parent star, just as the moon always the same side to the Earth.

Previous simulations published in a 2016 paper in the journal Astronomy & Astrophysicsmodeled a hypothetical atmosphere on Proxima Centauri b and suggested that the star-facing hemisphere of the exoplanet could be baked under an intense shine, while a room with a view on the ocean would be frozen. Therefore, only a circle of warm sea could exist on Proxima Centauri b — a scenario, Del Genio’s team calls “eyeball Earth.”

But the new simulations were more extensive than the previous one; it is also a dynamic, circulating ocean, which was capable of transferring heat from one side of the exoplanet to the other very effectively. In one of the researchers also show that the motion of the atmosphere and the ocean combined, so that “although the night side never sees a starlight, there is a band of liquid water that continued around the equatorial region,” Del Genio told Live Science.

He likened the spread of heat to our own planet’s sea climate. The AMERICAN east coast is balmier than it would otherwise be, he said, because the gulf stream carries warm water from the tropics. In California, by contrast, the ocean streams of cold water from the North and the west coast is colder than would otherwise be the case, Del Genio added.

The team ran 18 separate simulation scenarios in total, looking at the effects of large continents, thin atmosphere, atmospheric compositions, and even changes in the amount of salt in the ocean. In almost all models, Proxima Centauri b ended with the open ocean, that persisted for at least a part of the surface.

“The larger the fraction of the planet with liquid water, the better the chances are that if there is a life there is, we can find evidence of that life with future telescopes,” Del Genio said.

Ravi Kopparapu, a geoscientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, who was not involved in the study, agreed.

“I find it exciting that some of these climate outcomes can be observed,” Kopparapu told Live Science. The next generation facilities like the Extremely Large Telescope under construction in Chile, would be able to witness the heat comes from Proxima Centauri b, and differentiation are possible surface conditions, he added.

Originally published on Live Science.


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