Stochastic accretion of the Earth

Sossi, Paolo A.; Stotz, Ingo L.; Jacobson, Seth A.; Morbidelli, Alessandro und O'Neill, Hugh St C. (2022): Stochastic accretion of the Earth. In: Nature Astronomy, Bd. 6, Nr. 8: S. 951-960

Abstract

Chondritic meteorites are thought to be representative of the material that formed the Earth. However, the Earth is depleted in volatile elements in a manner unlike that observed in any chondrite, and yet these elements retain chondritic isotope ratios. Here we use N-body simulations to show that the Earth did not form only from chondrites, but by stochastic accretion of many precursor bodies whose variable compositions reflect the temperatures at which they formed. Earth's composition is reproduced when the initial temperatures of planetesimal- to embryo-sized bodies are set by disk accretion rates of (1.08 +/- 0.17) x 10(-7) solar masses per year, although they may be perturbed by Al-26 heating on bodies formed at different times. Our model implies that a heliocentric gradient in composition was present in the protoplanetary disk and that planetesimals formed rapidly within similar to 1 Myr, consistent with radiometric volatile depletion ages of the Earth.

• Dokumententyp: Zeitschriftenartikel
• Fakultät: Geowissenschaften > Department für Geo- und Umweltwissenschaften
• Themengebiete: 500 Naturwissenschaften und Mathematik > 550 Geowissenschaften, Geologie
• ISSN: 2397-3366
• Sprache: Englisch