A nearby exoplanet that orbits within the habitable zone of a star only 4.2 light-years from Earth can harbor a vast ocean, increasing its chances of sustaining life.
Since its discovery, questions about the surface conditions of Proxima b have been swirled; the mass of the planet is approximately 1.3 times greater than that of the Earth, and the red dwarf star that surrounds it is similar in age to our sun.
Studies in recent years, however, have raised hopes for their livability and have knocked them down.
Now, a new study has once again raised the possibility that Proxima b is compatible with life, suggesting that, under the right conditions, the exoplanet could contain liquid water.
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Since its discovery, questions about the surface conditions of Proxima b have been swirled; the mass of the planet is approximately 1.3 times greater than that of the Earth, and the red dwarf star that surrounds it is similar in age to our sun. Artist's impression
"The main message of our simulations is that there is a decent chance that the planet is habitable," Anthony Del Genio, a planetary scientist at NASA's Goddard Institute for Space Studies, told LiveScience.
In the study published this month in the journal Astrobiology, the researchers ran what are said to be the first climatic simulations of Proxima b with a dynamic ocean.
It is believed that the planet is blocked by tides with its star, Proxima Centauri, which means it would have a permanent "side of the day" and a "night side".
While the water on the side remaining in the dark would freeze, that is not necessarily the case on the other side.
"Climate models with static oceans suggest that Proxima b could harbor a surface ocean of small days despite its weak instellation," the researchers explain in the new study.
With a dynamic (moving) ocean considered for the first time, the extension of this liquid water becomes much more significant, in some cases even submerging in parts of the night side.
The simulations showed that "with a dynamic ocean, a hypothetical Proxima Centauri b ocean cover with an atmosphere similar to that of modern Earth can have a habitable climate with a wide open ocean region, extending into night at low latitudes "
The researchers modeled for different levels of salinity and atmospheric concentrations of greenhouse gases, each of which could play in the size of the liquid regions.
Proxima b orbits the red dwarf Proxima Centauri, which is part of a triple system that includes the binary pair Alpha Centauri A and B. The impression of an artist is represented
WHAT MAKES IT UNIQUE TO PROXIMA B?
Distance: This is the closest terrestrial planet we could find.
Orbiting our nearest star, the planet is only four light-years away.
The missions to send spacecraft to the planet to examine for signs of life are already in planning, and could happen in a few decades.
Composition: The planet is rocky and similar in size to Earth.
Temperature: It is located in the "habitable zone" of its star, which means that there could be liquid water on its surface, a key ingredient for extraterrestrial life.
The temperature on the planet's surface could be between -90 ° and 30 ° Celsius (-130 and 86 Fahrenheit).
Atmosphere: If Proximab has an atmosphere, the simple ingredients – water, carbon dioxide and rock – that are necessary for the formation of biochemical cycles that we call life, could all be present and interacting on the surface of the planet.
In more than a dozen simulations, the team discovered that the exoplanet almost always had some kind of liquid ocean.
But, do not get excited to take a dip for the moment.
"We found that a Proxima b covered by the oceans could have a much wider area of surface liquid water, but at much cooler temperatures than those suggested above, due to the transport of ocean heat and / or the depression of the freezing point by salinity, "the researchers wrote.