EFFECT OF SURFACE-MANTLE WATER EXCHANGE PARAMETERIZATIONS ON EXOPLANET OCEAN DEPTHS
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Univ Arizona, Dept Planetary Sci, Lunar & Planetary LabIssue Date
2016-11-16Keywords
methods: analyticalplanets and satellites: interiors
planets and satellites: oceans
planets and; satellites: tectonics
planets and satellites: terrestrial planets
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EFFECT OF SURFACE-MANTLE WATER EXCHANGE PARAMETERIZATIONS ON EXOPLANET OCEAN DEPTHS 2016, 832 (1):54 The Astrophysical JournalJournal
The Astrophysical JournalRights
© 2016. The American Astronomical Society. All rights reserved.Collection Information
This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at repository@u.library.arizona.edu.Abstract
Terrestrial exoplanets in the canonical habitable zone may have a variety of initial water fractions due to random volatile delivery by planetesimals. If the total planetary water complement is high, the entire surface may be covered in water, forming a "waterworld." On a planet with active tectonics, competing mechanisms act to regulate the abundance of water on the surface by determining the partitioning of water between interior and surface. Here we explore how the incorporation of different mechanisms for the degassing and regassing of water changes the volatile evolution of a planet. For all of the models considered, volatile cycling reaches an approximate steady state after similar to 2 Gyr. Using these steady. states, we find that if volatile cycling is either solely dependent on temperature or seafloor pressure, exoplanets require a high abundance (greater than or similar to 0.3% of total mass) of water to have fully inundated surfaces. However, if degassing is more dependent on seafloor pressure and regassing mainly dependent on mantle temperature, the degassing rate is relatively large at late times and a steady. state between degassing and regassing is reached with a substantial surface water fraction. If this hybrid model is physical, super-Earths with a total water fraction similar to that of the Earth can become waterworlds. As a result, further understanding of the processes that drive volatile cycling on terrestrial planets is needed to determine the water fraction at which they are likely to become waterworlds.ISSN
1538-4357Version
Final published versionSponsors
NASA headquarters under the NASA Earth and Space Science Fellowship Program [PLANET14F-0038]; NASA Astrobiology Institute Virtual Planetary Laboratory; NASA [NNH05ZDA001C]Additional Links
http://stacks.iop.org/0004-637X/832/i=1/a=54?key=crossref.2920c6b9e1db2826ebfcd63a5f8b8116Scopus Count
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