Fresh research from the Georgia Institute of Technology has shed some light on a potential exoplanet 500 light-years away that is very much like Earth.
Named Kepler-186f, the planet is the first identified Earth-sized planet outside our solar system and has been found orbiting a star in the habitable zone, meaning it's just the right distance from its host star for liquid water to pool on the surface.
Published in The Astronomical Journal, the Georgia Tech study used simulations to analyse and identify the exoplanet's spin axis dynamics, data which determine how much a planet tilts on its axis and how that tilt angle evolves over time. If Kepler-186f's axial tilt is sufficient, it would suggest the planet has seasons and climate because it affects how sunlight strikes the planet's surface.
The research indeed suggested that the planet's axis is very stable, much like the Earth, making it likely that it has regular seasons and a stable climate.
The Georgia Tech team also thinks the same is true for Kepler-62f, another Earth-sized planet orbiting around a star about 1,200 light-years away from us.
Kepler-186f is less than 10 per cent larger in radius than Earth, but its mass, composition and density remain a mystery. It orbits its host star every 130 days. According to NASA, the brightness of that star at high noon, while standing on 186f, would appear as bright as the sun just before sunset here on Earth. Kepler-186f is located in the constellation Cygnus as part of a five-planet star system.
As for Kepler-62f, it was the most Earth-like exoplanet until scientists noticed 186f in 2014. It's about 40 per cent larger than our planet and is likely a terrestrial or ocean-covered world. It's in the constellation Lyra and is the outermost planet among five exoplanets orbiting a single star.
However, the scientists say while that's not to say if either exoplanet has water, let alone life, both are relatively good candidates.
"Our study is among the first to investigate climate stability of exoplanets and adds to the growing understanding of these potentially habitable nearby worlds," said Georgia Tech Assistant Professor Gongjie Li, who led the study.
"I don't think we understand enough about the origin of life to rule out the possibility of their presence on planets with irregular seasons," added Shan. "Even on Earth, life is remarkably diverse and has shown incredible resilience in extraordinarily hostile environments.
"But a climatically stable planet might be a more comfortable place to start."
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