Formation of terrestrial planets by convergent migration driven by pair of planetary embryos

Formation of terrestrial planets by convergent migration driven by a pair of planetary embryos

Status report of: Electronic print archive
Posted: Monday September 27 2021

M. Brož, O. Chrenko, D. Nesvorný, N. Dauphas

The massive nuclei of giant planets are believed to have formed in a gas disk by accretion of pebble-sized particles whose accretion cross-section is enhanced by the aerodynamic drag of the gas. [1][2]. A commonly held view is that the terrestrial system of planets was formed later (30-200 Myr after the gas disc dispersed) by giant collisions of dozens of protoplanets about the size of Mars. [3]. Here, we propose, instead, that the terrestrial planets formed earlier by the convergent gas-driven migration of protoplanets to ∼1au (ref. [4] invoked a different process to concentrate the planetesimals). To study the situations in which convergent migration occurs, we have developed a radio-hydrodynamic model with realistic opacities [5][6] to determine the thermal structure of gas and pebble disks in the area of ​​planet Earth. We find that protoplanets grow rapidly through mutual collisions and pebble accretion, and gain orbital eccentricities through gravitational scattering and the hot drag effect. [7][8]. The orbital structure of the Earth’s planetary system is well reproduced in our simulations, including its tight mass concentration at 0.7-1 au and the small sizes of Mercury and Mars. The temperature of the early-stage protosolar disc exceeds 1500 K within 0.4 au, implying that Mercury has developed in a highly reducing environment, alongside the lines of evaporation of iron and silicates, influencing the bulk composition of Mercury. [9]. In an advanced cold gas disc, accretion of icy / hydrated pebbles would contribute to the Earth’s water balance.

Comments: original submission; final verse. is available on the NA website

Topics: Terrestrial and planetary astrophysics (astro-ph.EP)

Journal reference: Nature astronomy, 5, 898-902, 2021

DO I: 10.1038 / s41550-021-01383-3

Quote as: arXiv: 2109.11385 [astro-ph.EP] (or arXiv: 2109.11385v1 [astro-ph.EP] for this version)

History of submissions

From: Miroslav Brož

[v1] Thu 23 Sep 2021 14:02:39 UTC (12,452 KB)


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