Two exoplanets orbiting not-so-distant alien sun called Teegarden may orbit their star in the right spot for them to have liquid water on their surface and even possible alien life.
The two alien worlds may be home to liquid oceans of water if they have very thin atmospheres or relatively thick ones.
These exoplanets, called Teegarden b and c, were discovered in June of 2019, and one of them, the closest to its star Teegarden b, was characterized by astronomers as the most similar exoplanet to Earth ever found.
Now, astrophysicists Amri Wandel of the Hebrew University of Jerusalem, and Lev Tal-Or of the University of Tel Aviv have calculated the kind of atmosphere these worlds should have for liquid water to swarm their surfaces.
Both Teegarden b and Teegarden c are tidally locked, which means that only one of their faces points towards their small host star, while the other remains in eternal darkness. Our moon, for example, is tidally locked to Earth, reason why we only see one of its sides from Earth; its “near side.”
If they did not have an atmosphere that surrounds them, these planets would have a fiery side and another icy one, but if there were, the scenario could be quite different, and the planets could be home to winds that ma transport heat to the entire surface of the planet, keeping temperatures just right.
The astronomers found that as long as these exoplanets have atmospheres that are between a third and 17 times as dense as Earth’s, then it would probably possible that at least one region of one of these worlds harbors water and life.
On Earth, surface temperatures vary between the poles and the equator, but to a relatively limited extent.
In contrast, worlds with tidal locking like those of Teegarden have more extreme variations from one region to another.
“This gives it a wider range so that possible atmospheres allow the development of life,” said Wandel, speaking to the New Scientist.
Astrophysics Jessie Christiansen – who was not involved in the recent study – disagrees and told the New Scientist magazine that tidally locked planets could present obstacles to life development as we know it.
The astronomer argues that some experts believe that having a day-night cycle is key for living organisms. This, for example, would not exist in a world that’s tidally locked to their host star, resulting in the planet always facing the sun with one side. In addition to that, it is believed that tidally locked worlds may have a suppressed magnetic field, which means that such exoplanets would become overly exposed to harmful radiation from their host star, hampering possibilities or organisms surviving on the surface.
But although the two alien worlds orbiting Teegarden may have a few obstacles to overcome in order to host alien life on their surface, Christiansen acknowledged that both worlds are “incredibly tantalizing.”
“These new planets will remain under scrutiny for some time while we explore these possibilities,” revealed Christiansen.
The study was published in the Astrophysical Journal Letters.