000006835 001__ 6835
000006835 005__ 20240217112909.0
000006835 0247_ $$2DOI$$a10.1051/0004-6361/201935714
000006835 037__ $$aSCART-2024-0091
000006835 100__ $$aHakim, Kaustubh
000006835 245__ $$aThermal evolution of rocky exoplanets with a graphite outer shell
000006835 260__ $$c2019
000006835 520__ $$aContext. The presence of rocky exoplanets with a large refractory carbon inventory is predicted by chemical evolution models of protoplanetary disks of stars with photospheric C/O > 0.65, and by models studying the radial transport of refractory carbon. High-pressure high-temperature laboratory experiments show that most of the carbon in these exoplanets differentiates into a graphite outer shell. Aims. Our aim is to evaluate the effects of a graphite outer shell on the thermal evolution of rocky exoplanets containing a metallic core and a silicate mantle. Methods. We implemented a parameterized model of mantle convection to determine the thermal evolution of rocky exoplanets with graphite layer thicknesses up to 1000 km. Results. We find that because of the high thermal conductivity of graphite, conduction is the dominant heat transport mechanism in a graphite layer for long-term evolution (>200 Myr). The conductive graphite shell essentially behaves like a stagnant lid with a fixed thickness. Models of Kepler-37b (Mercury-size) and a Mars-sized exoplanet show that a planet with a graphite lid cools faster than a planet with a silicate lid, and a planet without a stagnant lid cools the fastest. A graphite lid needs to be approximately ten times thicker than a corresponding silicate lid to produce similar thermal evolution.
000006835 594__ $$aNO
000006835 700__ $$avan den Berg, Arie
000006835 700__ $$aVazan, Allona
000006835 700__ $$aHöning, Dennis
000006835 700__ $$avan Westrenen, Wim
000006835 700__ $$aDominik, Carsten
000006835 773__ $$cA152$$pAstronomy & Astrophysics$$v630$$y2019
000006835 8560_ $$fkaustubh.hakim@ksb-orb.be
000006835 85642 $$ahttps://doi.org/10.1051/0004-6361/201935714
000006835 8564_ $$s1000743$$uhttp://publi2-as.oma.be/record/6835/files/Hakim2019EvolutionGraphiteExoplanets.pdf
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000006835 905__ $$apublished in
000006835 980__ $$aREFERD