The energetics and convective vigor of mixed-mode heating: Velocity scalings and implications for the tectonics of exoplanets

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dc.citation.firstpage9469en_US
dc.citation.issueNumber18en_US
dc.citation.journalTitleGeophysical Research Lettersen_US
dc.citation.lastpage9474en_US
dc.citation.volumeNumber43en_US
dc.contributor.authorWeller, Matthew B.en_US
dc.contributor.authorLenardic, Adrianen_US
dc.date.accessioned2017-05-19T19:09:39Zen_US
dc.date.available2017-05-19T19:09:39Zen_US
dc.date.issued2016en_US
dc.description.abstractThe discovery of large terrestrial (~1 Earth mass (Me) to < 10 Me) extrasolar planets has prompted a debate as to the likelihood of plate tectonics on these planets. Canonical models assume classic basal heating scaling relationships remain valid for mixed heating systems with an appropriate internal temperature shift. Those scalings predict a rapid increase of convective velocities (Vrms) with increasing Rayleigh numbers (Ra) and non-dimensional heating rates (Q). To test this we conduct a sweep of 3-D numerical parameter space for mixed heating convection in isoviscous spherical shells. Our results show that while Vrms increases with increasing thermal Ra, it does so at a slower rate than predicted by bottom heated scaling relationships. Further, the Vrms decreases asymptotically with increasing Q. These results show that independent of specific rheologic assumptions (e.g., viscosity formulations, water effects, and lithosphere yielding), the differing energetics of mixed and basally heated systems can explain the discrepancy between different modeling groups. High-temperature, or young, planets with a large contribution from internal heating will operate in different scaling regimes compared to cooler-temperature, or older, planets that may have a larger relative contribution from basal heating. Thus, differences in predictions as to the likelihood of plate tectonics on exoplanets may well result from different models being more appropriate to different times in the thermal evolution of a terrestrial planet (as opposed to different rheologic assumptions as has often been assumed).en_US
dc.identifier.citationWeller, Matthew B. and Lenardic, Adrian. "The energetics and convective vigor of mixed-mode heating: Velocity scalings and implications for the tectonics of exoplanets." <i>Geophysical Research Letters,</i> 43, no. 18 (2016) Wiley: 9469-9474. https://doi.org/10.1002/2016GL069927.en_US
dc.identifier.doihttps://doi.org/10.1002/2016GL069927en_US
dc.identifier.urihttps://hdl.handle.net/1911/94295en_US
dc.language.isoengen_US
dc.publisherWileyen_US
dc.rightsArticle is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.en_US
dc.titleThe energetics and convective vigor of mixed-mode heating: Velocity scalings and implications for the tectonics of exoplanetsen_US
dc.typeJournal articleen_US
dc.type.dcmiTexten_US
dc.type.publicationpublisher versionen_US
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