Terrestrial Planet Formation from Two Source Reservoirs
This work describes new dynamical simulations of terrestrial planet formation. The simulations started at the protoplanetary disk stage, when planetesimals formed and accreted into protoplanets, and continued past the late stage of giant impacts. We explored the effect of different parameters, such...
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IOP Publishing
2025-01-01
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| Series: | The Astronomical Journal |
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| Online Access: | https://doi.org/10.3847/1538-3881/adf20a |
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| author | David Nesvorný Alessandro Morbidelli William F. Bottke Rogerio Deienno Max Goldberg |
| author_facet | David Nesvorný Alessandro Morbidelli William F. Bottke Rogerio Deienno Max Goldberg |
| author_sort | David Nesvorný |
| collection | DOAJ |
| description | This work describes new dynamical simulations of terrestrial planet formation. The simulations started at the protoplanetary disk stage, when planetesimals formed and accreted into protoplanets, and continued past the late stage of giant impacts. We explored the effect of different parameters, such as the initial radial distribution of planetesimals and Type-I migration of protoplanets, on the final results. In each case, a thousand simulations were completed to characterize the stochastic nature of the accretion process. In the model best able to satisfy various constraints, Mercury, Venus, and Earth accreted from planetesimals that formed early near the silicate sublimation line at ≃0.5 au and migrated by disk torques. For Venus and Earth to end up at 0.7–1 au, Type-I migration had to be directed outward, for example, as the magnetically driven winds reduced the surface gas density in the inner part of the disk. Mercury was left behind near the original ring location. We suggest that Mars and multiple Mars-sized protoplanets grew from a distinct outer source of planetesimals at 1.5–2 au. While many migrated inward to accrete onto the proto-Earth, our Mars was the lone survivor. This model explains: (1) the masses and orbits of the terrestrial planets, (2) the chemical composition of the Earth, where ∼70% and ∼30% come from reduced inner-ring and more-oxidized outer-ring materials, and (3) the isotopic differences of the Earth and Mars. It suggests that the Moon-forming impactor Theia plausibly shared a similar isotopic composition and accretion history with that of the proto-Earth. |
| format | Article |
| id | doaj-art-c7da774c87894a9fbce3090ecec33754 |
| institution | Kabale University |
| issn | 1538-3881 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astronomical Journal |
| spelling | doaj-art-c7da774c87894a9fbce3090ecec337542025-08-22T11:25:12ZengIOP PublishingThe Astronomical Journal1538-38812025-01-01170318010.3847/1538-3881/adf20aTerrestrial Planet Formation from Two Source ReservoirsDavid Nesvorný0https://orcid.org/0000-0002-4547-4301Alessandro Morbidelli1William F. Bottke2https://orcid.org/0000-0002-1804-7814Rogerio Deienno3https://orcid.org/0000-0001-6730-7857Max Goldberg4https://orcid.org/0000-0003-3868-3663Solar System Science & Exploration Division, Southwest Research Institute , 1301 Walnut Street, Suite 400, Boulder, CO 80302, USALaboratoire Lagrange, UMR7293, Université Côte d’Azur , CNRS, Observatoire de laCôte d’Azur, Bouldervard de l’Observatoire, 06304, Nice Cedex 4, FranceSolar System Science & Exploration Division, Southwest Research Institute , 1301 Walnut Street, Suite 400, Boulder, CO 80302, USASolar System Science & Exploration Division, Southwest Research Institute , 1301 Walnut Street, Suite 400, Boulder, CO 80302, USALaboratoire Lagrange, UMR7293, Université Côte d’Azur , CNRS, Observatoire de laCôte d’Azur, Bouldervard de l’Observatoire, 06304, Nice Cedex 4, FranceThis work describes new dynamical simulations of terrestrial planet formation. The simulations started at the protoplanetary disk stage, when planetesimals formed and accreted into protoplanets, and continued past the late stage of giant impacts. We explored the effect of different parameters, such as the initial radial distribution of planetesimals and Type-I migration of protoplanets, on the final results. In each case, a thousand simulations were completed to characterize the stochastic nature of the accretion process. In the model best able to satisfy various constraints, Mercury, Venus, and Earth accreted from planetesimals that formed early near the silicate sublimation line at ≃0.5 au and migrated by disk torques. For Venus and Earth to end up at 0.7–1 au, Type-I migration had to be directed outward, for example, as the magnetically driven winds reduced the surface gas density in the inner part of the disk. Mercury was left behind near the original ring location. We suggest that Mars and multiple Mars-sized protoplanets grew from a distinct outer source of planetesimals at 1.5–2 au. While many migrated inward to accrete onto the proto-Earth, our Mars was the lone survivor. This model explains: (1) the masses and orbits of the terrestrial planets, (2) the chemical composition of the Earth, where ∼70% and ∼30% come from reduced inner-ring and more-oxidized outer-ring materials, and (3) the isotopic differences of the Earth and Mars. It suggests that the Moon-forming impactor Theia plausibly shared a similar isotopic composition and accretion history with that of the proto-Earth.https://doi.org/10.3847/1538-3881/adf20aPlanet formationSolar system terrestrial planetsPlanetary migrationEarth-moon systemCosmochemistry |
| spellingShingle | David Nesvorný Alessandro Morbidelli William F. Bottke Rogerio Deienno Max Goldberg Terrestrial Planet Formation from Two Source Reservoirs The Astronomical Journal Planet formation Solar system terrestrial planets Planetary migration Earth-moon system Cosmochemistry |
| title | Terrestrial Planet Formation from Two Source Reservoirs |
| title_full | Terrestrial Planet Formation from Two Source Reservoirs |
| title_fullStr | Terrestrial Planet Formation from Two Source Reservoirs |
| title_full_unstemmed | Terrestrial Planet Formation from Two Source Reservoirs |
| title_short | Terrestrial Planet Formation from Two Source Reservoirs |
| title_sort | terrestrial planet formation from two source reservoirs |
| topic | Planet formation Solar system terrestrial planets Planetary migration Earth-moon system Cosmochemistry |
| url | https://doi.org/10.3847/1538-3881/adf20a |
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