Astronomers from the University of California, Irvine (UCI) described in their study, titled "Terminator Habitability: The Case for Limited Water Availability on M-dwarf Planets," published in The Astrophysical Journal, how extraterrestrial life could potentially exist in a region called "terminator zone."
UCI Department of Physics & Astronomy postdoctoral researcher Ana Lobo, the study's lead author, explained that this area is a ring on distant exoplanets with a permanent day side and a permanent night side.
First Study on Terminator Zone's Habitability
Lobo said that exoplanets with terminator zones are particularly common and orbit around stars that make up 70% of the stars seen in the night sky. These stars are called M-dwarf stars, which tend to be dimmer than the Sun.
According to SciTech Daily, the terminator zone is the dividing line between the day and night sides of the exoplanets that have them. Scientists believe that this region exits in a zone with a habitable climate that is "just right" to host extraterrestrial life where it is neither too hot nor too cold.
Lobo noted that since water is an essential element for life, it is important that a planet has a sweet spot with the right temperature for liquid water. The night sides of terminator planets would be too cold that any water would be frozen in ice, while the day side could be too hot that water would not exist.
Lobo and co-researcher Aomawa Shields, an associate professor of physics and astronomy at UCI, modeled the possible temperature in terminator planets using software to model Earth's climate.
This could be the first time scientists have demonstrated that such exoplanets may retain habitable climates while limited to the terminator zone. Researchers usually focused on ocean-covered exoplanets in their hunt for habitable possibilities.
But the recent study showed that terminator planets could potentially be viable refuges for life, expanding possibilities available to life-seeking astronomers.
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Recognizing Exoplanets With Terminator Zones
Lobo said that one key to finding terminator planets is pinpointing what kind of terminator zone can retain liquid water. According to a similar report by Science Daily, a water-rich planet could lose its liquid water on the side facing its star and will be covered in a thick layer of vapor.
The scientists showed that if there is a lot of land on the exoplanet, the "terminator habitability" could potentially exist there. This new and exotic habitability is no longer an idea from science fiction as their findings show that such states could have a habitable climate.
Identifying terminator zones as possible shelters for life also implies that astronomers will need to change their approach to studying exoplanet climates in finding signs of life because the biosignatures may only be present in certain sections of the planet's atmosphere.
The research will also assist in influencing future attempts by teams searching for planets that may harbor alien life using observatories such as NASA's James Webb Space Telescope or the Large Ultraviolet Optical Infrared Surveyor.
Check out more news and information on Exoplanets in Science Times.
