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It's a bit of a roller coaster for scientists studying Proxima b, a planet similar to Earth, sitting around Proxima Centauri, the stellar neighbor closest to our solar system.
When astronomers confirmed their existence in 2016, scientists rushed to determine if this exoplanet could shelter life. Although it was in the star zone, a number of studies quickly cast doubt on the possibility of extraterrestrial life.
But now, a study conducted by NASA has offered an olive branch to Proxima b believers. Scientists have used sophisticated 3D simulation techniques to produce a number of scenarios in which life could survive on the exoplanet. Their research was recently published in the journal astrobiology.
Various obstacles stand out on Proxima b. Although it is close enough for liquid water to theoretically persist, scientists do not know if it has any. "We do not know if [the exoplanet] even has an atmosphere and if so, if it has water. Without these, life as we know it can not exist, "said one of the authors of the study, Anthony Del Genio, NASA's Goddard Institute for Space Studies. Universe today. Del Genio did not immediately respond to NewsweekRequest for comment.
Even if it contained water in the past, there are good reasons to think that the planet is arid now. Its host star is a red dwarf much cooler and smaller than our own sun, said Del Genio, with a nearby livability zone. Because it's a very active star, the planets inside this gold ring are threatened by powerful flares.
In March 2017, a Proxima Centauri flare destroyed Proxima b. Scientists believe that these flashes of brightness may have slowly destroyed the planet's atmosphere and eliminated its water.
But a number of scenarios could have left Proxima b with at least a little water, explained Del Genio. If the planet was very wet when it formed, for example, some of this liquid could persist. He may have also begun to move away from Proxima Centauri and slowly get closer to the star, providing protection against powerful flares in his early days, he said. Universe today.
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The researchers' software simulated several climate scenarios. In one model, the planet had an Earth-like atmosphere and in another, it had one like Mars. In one simulation, she was locked on her star and in another on a huge ocean.
"For every configuration we imagine, we are implementing a 3D global climate model adapted from the Earth's climate model that we use to project 21st century warming," Del Genio said. include a "dynamic" ocean. "
Where other studies have imagined an ocean that remains calm, the currents of a dynamic ocean will transfer hot water to colder areas, he added.
The team discovered that this type of ocean could help Proxima maintain at least some surface water in a wide range of scenarios. Even the dark side of a planet in danger could remain habitable with a dynamic ocean. Saltwater, for example, could keep liquid water even below its normal freezing point.
Scientists hope that future instruments, such as NASA's James Webb Space Telescope, will reveal more details about exoplanets like Proxima b. The Kepler Space Observatory, launched in 2009, has discovered thousands of planets in its lifetime.
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