%0 Generic %1 johansen2022anatomy %A Johansen, Anders %A Ronnet, Thomas %A Schiller, Martin %A Deng, Zhengbin %A Bizzarro, Martin %D 2022 %K Pebbles formation %T Anatomy of rocky planets formed by rapid pebble accretion III. Partitioning of volatiles between core, mantle and atmosphere %U http://arxiv.org/abs/2207.09807 %X Volatile molecules containing hydrogen, carbon and nitrogen atoms are key components of planetary atmospheres. In the pebble accretion model for terrestrial planet formation, these volatile species are accreted during the main planetary formation phase. We model here the partitioning of volatiles within a growing planet and the outgassing to the surface. The core stores more than 90% of the hydrogen and carbon budgets of Earth for realistic values of the partition coefficients of H and C between metal and silicate melts. The magma oceans of Earth and Venus are sufficiently deep to undergo oxidation of ferrous Fe$^2+$ to ferric Fe$^3+$. This increased oxidation state leads to the outgassing of primarily CO$_2$ and H$_2$O from the magma ocean of Earth. In contrast, the oxidation state of Mars' mantle remains low and the main outgassed hydrogen carrier is H$_2$. This hydrogen easily escapes the atmosphere due to the XUV irradiation from the young Sun, dragging with it the majority of the CO, CO$_2$, H$_2$O and N$_2$ contents of the atmosphere. A small amount of surface water is maintained on Mars, in agreement with proposed ancient ocean shorelines, assuming a slightly higher mantle oxidation. Nitrogen distributes relatively evenly between the core and the atmosphere due to its extremely low solubility in magma; burial of large reservoirs of nitrogen in the core is thus not possible. The overall low N contents of Earth disagree with the high abundance of N in all chondrite classes and favours volatile delivery by pebble snow. Our model of rapid rocky planet formation by pebble accretion displays broad consistency with the volatile contents of the Sun's terrestrial planets. The diversity of the terrestrial planets can therefore be used as benchmark cases to calibrate models of extrasolar rocky planets and their atmospheres.

@misc{johansen2022anatomy, abstract = {Volatile molecules containing hydrogen, carbon and nitrogen atoms are key components of planetary atmospheres. In the pebble accretion model for terrestrial planet formation, these volatile species are accreted during the main planetary formation phase. We model here the partitioning of volatiles within a growing planet and the outgassing to the surface. The core stores more than 90% of the hydrogen and carbon budgets of Earth for realistic values of the partition coefficients of H and C between metal and silicate melts. The magma oceans of Earth and Venus are sufficiently deep to undergo oxidation of ferrous Fe$^{2+}$ to ferric Fe$^{3+}$. This increased oxidation state leads to the outgassing of primarily CO$_2$ and H$_2$O from the magma ocean of Earth. In contrast, the oxidation state of Mars' mantle remains low and the main outgassed hydrogen carrier is H$_2$. This hydrogen easily escapes the atmosphere due to the XUV irradiation from the young Sun, dragging with it the majority of the CO, CO$_2$, H$_2$O and N$_2$ contents of the atmosphere. A small amount of surface water is maintained on Mars, in agreement with proposed ancient ocean shorelines, assuming a slightly higher mantle oxidation. Nitrogen distributes relatively evenly between the core and the atmosphere due to its extremely low solubility in magma; burial of large reservoirs of nitrogen in the core is thus not possible. The overall low N contents of Earth disagree with the high abundance of N in all chondrite classes and favours volatile delivery by pebble snow. Our model of rapid rocky planet formation by pebble accretion displays broad consistency with the volatile contents of the Sun's terrestrial planets. The diversity of the terrestrial planets can therefore be used as benchmark cases to calibrate models of extrasolar rocky planets and their atmospheres.}, added-at = {2022-12-24T19:48:45.000+0100}, author = {Johansen, Anders and Ronnet, Thomas and Schiller, Martin and Deng, Zhengbin and Bizzarro, Martin}, biburl = {https://www.bibsonomy.org/bibtex/2527c8ab11656f9219ec48551fdef41a0/ijiraq}, description = {Anatomy of rocky planets formed by rapid pebble accretion III. Partitioning of volatiles between core, mantle and atmosphere}, interhash = {65dc0b11f207be805f2c581c145817d3}, intrahash = {527c8ab11656f9219ec48551fdef41a0}, keywords = {Pebbles formation}, note = {cite arxiv:2207.09807Comment: Submitted to Astronomy & Astrophysics, revised according to referee report. Comments welcome}, timestamp = {2022-12-24T19:48:45.000+0100}, title = {Anatomy of rocky planets formed by rapid pebble accretion III. Partitioning of volatiles between core, mantle and atmosphere}, url = {http://arxiv.org/abs/2207.09807}, year = 2022 }