Proxima b is a planet discovered outside our solar system in 2016. Proxima Centauri is a small, cool red-dwarf star located just 4.2 light-years from the sun. It is the closest planet to the surface of Earth; still, scientists know very little about this planet. Its mass is at least 1.3 times that of Earth, and it goes around its parent star every 11 days.
People have wondered whether it could be capable of sustaining life or not. It is an Earth-sized planet that orbits closest to our sun. Researchers have found that, under a wide range of conditions, Proxima b can sustain enormous areas of liquid water on its surface. Thus, it has potential chances to harbor living organisms. Del Genio, a planetary scientist, had guessed that it had an atmosphere and an ocean on its surface.
Proxima Centauri b orbits in its star’s habitable zone. It means that it’s just at the right distance to receive enough starlight to keep its surface above the freezing temperature of the water. But this zone is extremely close to the star. So, it’s likely that the planet may get locked by the gravitational pull of its parent star. It shows that the same side of Proxima b always faces its parent star, much like how the moon still shows the same side to Earth.
Scientists predict a “hypothetical atmosphere” on Proxima Centauri b. They suggested that the star-facing hemisphere of the planet might be extremely hot, and the other space-facing region frozen with ice. Therefore, only a circle of the warm sea might exist on this planet to which Del Genio’s team calls “eyeball Earth.” But the new researches are even more complicated. They showed the existence of a dynamic, circulating ocean that transfers heat from one side of the exoplanet to the other effectively. This heat circulation seems very similar to our planet’s seaside climates. All of the models presented so far, Proxima b ended up having an open ocean that persisted over at least some part of its surface.
“The larger the fraction of the planet with liquid water, the better the odds that if there’s life. We can find evidence of that life with future telescopes,” Del Genio said.
In a new Nasa-led study, a team of scientists has investigated various climate scenarios that indicate that Proxima b could still have enough water to support life.
But habitability is not as simple as it seems. There are also other requirements to sustain life on another planet, especially if it is out of our solar system. Such type of planets faces a lot of challenges when it comes to habitability. The first reason could be its closeness to its parent star. The absence of Greenhouse effect will subject it to intense radiations (X-rays and extreme ultraviolet fluxes) and solar wind. All these factors contribute to catastrophic water and atmospheric loss.
However, still, there is a lot that we don’t know about the evolutionary history of the planet. There are multiple scenarios in which habitability is possible. But the problem is Proxima b is an M star or “red dwarf.” These stars are much smaller and cooler than our sun. In their early lives, they are bright and hot. So, this sudden and changing climate of a planet can vanquish life before it had the chance to take hold. In the coming years, next-generation instruments are expected to play a significant role in the detection and characterization of exoplanets.
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