A short timescale for terrestrial planet formation from Hf–W chronometry of meteorites

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Abstract
Determining the chronology for the assembly of planetary bodies in the early Solar System is essential for a complete understanding of star- and planet-formation processes. Various radionuclide chronometers (applied to meteorites) have been used to determine that basaltic lava flows on the surface of the asteroid Vesta formed within 3 million years (3 Myr) of the origin of the Solar System1,2,3. Such rapid formation is broadly consistent with astronomical observations of young stellar objects, which suggest that formation of planetary systems occurs within a few million years after star formation4,5. Some hafnium–tungsten isotope data, however, require that Vesta formed later6 ( ∼ 16 Myr after the formation of the Solar System) and that the formation of the terrestrial planets took a much longer time7,8,9,10 (62-14+4504 Myr). Here we report measurements of tungsten isotope compositions and hafnium–tungsten ratios of several meteorites. Our measurements indicate that, contrary to previous results7,8,9,10, the bulk of metal–silicate separation in the Solar System was completed within 1,2,3,4,5, and are also in agreement with dynamic accretion models11,12,13 that predict a relatively short time ( ∼ 10 Myr) for the main growth stage of terrestrial planet formation.