Climate and orbit models reveal that Earth-like planet Kepler-62f may be able to sustain life, according to experts.
Kepler-62f is located some 1,200 light-years away from the Earth and is about 40 percent bigger than our planet. In a study about this exoplanet, lead author Aomawa Shields from the University of California Los Angeles said that Kepler-62f may be rocky and may contain oceans.
In 2013, NASA's Kepler mission was able to discover the planet, but failed to gather sufficient information about the makings of its atmosphere, as well as the shape of its orbit. The primary data they gathered at that time was that Kepler-62f was the outermost planet out of the five other ones surrounding a star that is lesser in size and lower in temperature than the sun.
The research team then set out on a study to identify if the planet may sustain life. They specifically came up with scenarios of possible atmospheric conditions and orbital shape of Kepler-62f.
"We found there are multiple atmospheric compositions that allow it to be warm enough to have surface liquid water," said Shields." This makes it a strong candidate for a habitable planet."
The researchers then made computer simulations based on three conditions. The first one involves Kepler-62f having an atmosphere that is as thick as the Earth's and up to 12 times thicker. The second scenario is having different carbon dioxide concentrations, ranging from a level same to the Earth's to up to 2,500 times higher. The team also tested varied orbital path configurations.
Carbon Dioxide
One of the important factors the team looked into in determining the habitability of Kepler-62f is its atmospheric carbon dioxide content. On Earth, the atmosphere is made up of about 0.04 percent carbon dioxide. For Kepler-62f to have enough warmth to sustain liquid water on its surface, it needs to have significantly more carbon dioxide, especially because it is farther from its star, which is also much cooler than the Earth's sun.
According to computer simulations, the team found many conditions wherein Kepler-62f can be habitable, anticipating varied amounts of carbon dioxide in the atmosphere.
Shields explained that a planet can be considered consistently habitable during the entire year if it has an atmosphere that is three to five times thicker than the Earth's and is made up fully of carbon dioxide. This is feasible for Kepler-62f due to the far distance it has from its star. As the planet gets colder over time, it would need the warmth that carbon dioxide can provide to its atmosphere.
Shields, however, revealed that Kepler-62f does not have processes that can produce ample carbon dioxide and that it only has levels comparable to the Earth's. Despite this, she said that certain orbital configurations could enable the planet to temporarily freeze for a particular time of the year, while other parts exhibit ice melting.
Orbital Path
The team also looked into the orbital path of Kepler-62f by making calculations of the planet's shape. They particularly used existing computer models to imitate the climate of the planet. This is the first time that astronomers combined climate and orbit models to study an exoplanet — a planet located outside of our solar system.
Shields said this technique may also be used to study whether other exoplanets much closer to Earth are habitable. She adds that as long as a planet is rocky, it may have a good chance of harboring life.
The technique may also enable scientists to discover habitable planets based on an array of factors, not identified by existing telescopes. It may also create a list of priority planets for experts which they may use in finding habitable planets.
At this point, astronomers are not yet sure whether exoplanets can sustain life, but Shields is positive in the quest for life in the universe.
So far, there have been over 2,300 exoplanets discovered. A few thousands are recognized as planet candidates, but only few are considered to belong in the "habitable zone," which means that they orbit their star close enough to keep them warm and sustain liquid water on their surface.
The study was published in the journal Astrobiology on May 13.
