"This is what real exploration is about.How close can a rocky planet be to a star, and still sustain water and life?Ī recently discovered exoplanet may be key to solving that mystery, providing important insights about conditions at the inner edge of a star’s habitable zone and why Earth and Venus developed so differently, according to new research led by Lisa Kaltenegger, director of the Carl Sagan Institute and associate professor of astronomy in the College of Arts and Sciences (A&S). "We don't know what this planet on the edge of habitability could be like, so we have to look," she said. Deeper investigation promises to provide valuable clues, Kaltenegger said. It's possible that LP 890-9c has no atmosphere and hosts no life, or that it resembles a Venus with thick clouds that would block light from reflecting and thus yield little information. If we see that it's already a full-blown Venus, then the water gets lost fast." "If it's still a hotter Earth-hot, but with liquid water and conditions for life-then the timeline is slower than we thought. "This planet is the first target where we can test these different scenarios," Kaltenegger said. How long those processes might take is unknown, and the astronomers say LP 890-9c provides a rare opportunity to explore that evolution. In between are phases Earth is expected to experience as the sun grows brighter and hotter with age, causing the oceans to gradually evaporate and fill the atmosphere with steam before boiling off entirely. The models span several scenarios thought to reflect stages of rocky planets' evolution, ranging from a "hot Earth" where life might still be possible, to a desolate Venus featuring a carbon dioxide atmosphere. They said liquid water or an atmosphere rich in water vapor was possible on LP 890-9c, which is about 40% larger than Earth and circles the small, cool star in 8.5 days. LP 890-9c is one of two super-Earths orbiting a red dwarf star located 100 light years from Earth, researchers announced last year. Kaltenegger is the lead author of "Hot Earth or Young Venus? A Nearby Transiting Rocky Planet Mystery," published in Monthly Notices of the Royal Astronomical Society: Letters. "It will teach us something fundamental about how rocky planets evolve with increasing starlight, and about what will one day happen to us and Earth." "Looking at this planet will tell us what's happening on this inner edge of the habitable zone-how long a rocky planet can maintain habitability when it starts to get hot," Kaltenegger said. Her team found LP 890-9c, which orbits close to the inner edge of its solar system's habitable zone, would look vastly different depending on whether it still had warm oceans, a steam atmosphere, or if it had lost its water-assuming it once had oceans like Earth's. "Super-Earth" LP 890-9c (also named SPECULOOS-2c) is providing important insights about conditions at the inner edge of a star's habitable zone and why Earth and Venus developed so differently, according to new research led by Lisa Kaltenegger, associate professor of astronomy at Cornell University.
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