000006838 001__ 6838
000006838 005__ 20240217114116.0
000006838 020__ $$a9789463234191
000006838 037__ $$aTHESIS-2024-0002
000006838 100__ $$aHakim, Kaustubh
000006838 245__ $$aDiving deep into rocky exoplanets
000006838 260__ $$c2018
000006838 300__ $$a150
000006838 502__ $$bPhD$$cUniversity of Amsterdam
000006838 520__ $$aApproximately one-third of about four thousand known exoplanets are possibly rocky in nature. The chemical and physical diversity of rocky exoplanets is well beyond that of the rocky planets of our solar system; Mercury, Venus, Earth, and Mars. In this thesis, we investigate the mineralogy, structure, evolution, and habitability of rocky exoplanets by implementing laboratory and computational tools from geosciences. We derive a new ab initio equation of state of iron using density functional theory valid at and beyond the core pressures of super-Earths. We show that extrapolations of equations of state to pressures beyond their validity range result in significant errors in estimating the interior properties of planets. We perform high-pressure high-temperature experiments on chemical mixtures representative of the bulk composition of carbon-rich rocky exoplanets and find that graphite (and diamond, depending on pressure) is the dominant carbon-bearing mineral. Such exoplanets likely contain an iron-rich core, a silicate mantle, and a graphite outer shell. We also show that silicon carbide, another carbon-bearing mineral thought to be an important constituent of these exoplanets, is stable only if all oxidized iron in the planetary interior is reduced to its metallic state. Using a parameterized mantle convection model, we compute the thermal evolution of rocky exoplanets with a graphite outer shell and find that the graphite shell exhibits a thermal shielding effect resulting in a slower cooling of the planet. A priori these graphite-shell exoplanets are likely uninhabitable because of a lack of life-building elements at their surface other than carbon, however thin graphite shells might still allow habitability.
000006838 594__ $$aNO
000006838 701__ $$aDominik, Carsten
000006838 701__ $$avan Westrenen, Wim
000006838 8560_ $$fkaustubh.hakim@ksb-orb.be
000006838 85642 $$ahttps://hdl.handle.net/11245.1/55f10977-2357-444c-b324-88a9963b8791
000006838 8564_ $$s43756255$$uhttp://publi2-as.oma.be/record/6838/files/Hakim2018PhDThesis.pdf
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000006838 8564_ $$s4813$$uhttp://publi2-as.oma.be/record/6838/files/Hakim2018PhDThesis.jpg?subformat=icon-180$$xicon-180
000006838 980__ $$aTHESIS