WATER TRAPPING ON TIDALLY LOCKED TERRESTRIAL PLANETS REQUIRES SPECIAL CONDITIONS

• Published in: The Astrophysical Journal
• Main Authors: Yang, Jun, Liu, Yonggang, Hu, Yongyun, Abbot, Dorian S.
• Other Authors: Yang, J (reprint author), Univ Chicago, Dept Geophys Sci, 5734 S Ellis Ave, Chicago, IL 60637 USA., Univ Chicago, Dept Geophys Sci, Chicago, IL 60637 USA., Princeton Univ, Woodrow Wilson Sch Publ & Int Affairs, Princeton, NJ 08544 USA., Peking Univ, Sch Phys, Dept Atmospher & Ocean Sci, Lab Climate & Atmosphere Ocean Studies, Beijing 100871, Peoples R China., Univ Chicago, Dept Geophys Sci, 5734 S Ellis Ave, Chicago, IL 60637 USA.
• Format: Journal/Newspaper
• Language: English
• Published: astrophysical journal letters 2014
• Subjects: astrobiology; planets and satellites: detection; planets and satellites: general; M-DWARF STARS; HABITABLE ZONES; EARTH; MODEL; EXOPLANETS; Ice Sheet; Sea ice
• Online Access: https://hdl.handle.net/20.500.11897/207432; https://doi.org/10.1088/2041-8205/796/2/L22

Surface liquid water is essential for standard planetary habitability. Calculations of atmospheric circulation on tidally locked planets around M stars suggest that this peculiar orbital configuration lends itself to the trapping of large amounts of water in kilometers-thick ice on the night side, potentially removing all liquid water from the day side where photosynthesis is possible. We study this problem using a global climate model including coupled atmosphere, ocean, land, and sea ice components as well as a continental ice sheet model driven by the climate model output. For a waterworld, we find that surface winds transport sea ice toward the day side and the ocean carries heat toward the night side. As a result, nightside sea ice remains O(10 m) thick and nightside water trapping is insignificant. If a planet has large continents on its night side, they can grow ice sheets O(1000 m) thick if the geothermal heat flux is similar to Earth's or smaller. Planets with a water complement similar to Earth's would therefore experience a large decrease in sea level when plate tectonics drives their continents onto the night side, but would not experience complete dayside dessiccation. Only planets with a geothermal heat flux lower than Earth's, much of their surface covered by continents, and a surface water reservoir O(10%) of Earth's would be susceptible to complete water trapping. http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000345503400001&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701 Astronomy & Astrophysics SCI(E) 7 ARTICLE [e-mail] 2 null 796