While astrobiologists are increasingly hoping to find microbial life dwelling on or just beneath the surface of Mars, exoplanet hunters have been continually searching for habitable worlds far from our local corner of the Milky Way. Just recently, three Earth-like planets were discovered hovering 40 light-years away from us, and a new study, published in the journal Astrobiology, may have just described another.
It’s roughly 40 percent larger than Earth, and it’s the outermost of five planets orbiting a star that is both smaller and cooler than our own Sun. Although it’s a lot further away – 1,200 light-years, to be precise – this new study suggests that the Kepler-62f may be able to sustain life.
First identified by the mechanical wunderkind that is the Kepler space observatory, little was known about it at the time. A team of researchers from the Universities of California Los Angeles (UCLA) and Washington turned to cutting-edge computer simulations in order to work out what it may be like to wander around on its surface.
“We found there are multiple atmospheric compositions that allow it to be warm enough to have surface liquid water,” Aomawa Shields, a National Science Foundation astronomy and astrophysics postdoctoral fellow in UCLA’s department of physics and astronomy, and the study’s lead author, said in a statement. “This makes it a strong candidate for a habitable planet.”
The relative sizes of recently discovered habitable-zone planets and Earth. From left to right: Kepler-69c, Kepler-62e, this study’s Kepler-62f, and our own pale blue dot. NASA/Ames/JPL-Caltech
The shape of the planet’s orbital path was the first thing that needed to be calculated. To do so, the team used a renowned computer model named HNBody; this was combined with two tried-and-tested climate change models to simulate its possible climate configurations as it orbited its star.
The models assumed the atmosphere of Kepler-62f could be the same thickness as Earth’s all the way up to 12 times as thick. A variety of concentrations of carbon dioxide in the atmosphere were also considered, ranging from the same as Earth’s to up to 2,500 times that.
Based on what we know about microbial life, and considering the dimness of the alien star, Kepler-62f would only be completely habitable throughout its entire orbit if its atmosphere was 3 to 5 times thicker than our own, and it was composed entirely of carbon dioxide. This would ensure that a potent greenhouse effect would be in operation, which would warm the planet to habitable levels for microscopic life.
The most likely orbital parameters calculated by the models suggest that the planet would indeed by far away enough from its star to allow carbon dioxide to steadily accumulate in the atmosphere over time, as opposed to being blasted away by powerful solar radiation. Even if there was only an Earth-typical amount of carbon dioxide in the atmosphere, the temperatures would still go above water’s freezing point for portions of the year.
The early Earth has a carbon dioxide-rich atmosphere thanks to prolonged volcanic activity. IM_photo/Shutterstock
Wherever you find water on Earth, there is life – and such an atmospheric configuration would allow liquid water to be present at the surface. With water and carbon dioxide, photosynthesizing alien life, if it exists there, could one day convert Kepler-62f’s atmosphere into one brimming with oxygen.
However, without a strong magnetic field, too much incoming solar radiation may render life at the surface impossible. Still, this somewhat damp and warm planet appears to be in the “habitable zone,” so that’s certainly something worth noting.