Age of Jupiter inferred from the distinct genetics and formation times of meteorites

Title	Age of Jupiter inferred from the distinct genetics and formation times of meteorites
Authors	Thomas S. Kruijer, Christoph Burkhardt, Gerrit Budde, Thorsten Kleine
Magazine	Proceedings of the National Academy of Sciences
Date	06/12/2017
DOI	10.1073/pnas.1704461114
Introduction	Jupiter, the Solar System's most massive planet, profoundly influenced the dynamics of the solar accretion disk. Determining Jupiter's age is therefore fundamental to understanding how the Solar System developed its current architecture. Although models indicate an early formation for Jupiter, its precise age has not been established until now. This research, through isotope analyses of meteorites, demonstrates that Jupiter's solid core began its formation within approximately 1 million years after the Solar System's commencement, positioning it as the oldest planet. Jupiter's swift development served as an efficient barrier against the inward flow of material across the disk, potentially explaining the absence of super-Earths in our Solar System. The age of Jupiter, the largest planet in our Solar System, has remained an open question. The formation of gas-giant planets likely involves the initial growth of substantial solid cores, followed by the accretion of gas onto these cores. Consequently, these gas-giant cores must have formed prior to the dissipation of the solar nebula, which probably occurred within less than 10 million years after Solar System formation. While such rapid core accretion has been successfully simulated, direct dating of their formation has previously not been possible. Here, by applying molybdenum and tungsten isotope measurements to iron meteorites, we illustrate that meteorites originate from two genetically distinct nebular reservoirs. These reservoirs coexisted and maintained spatial separation between approximately 1 million years and 3–4 million years after Solar System formation. The most probable mechanism for this effective separation is the formation of Jupiter, which opened a gap in the disk and hindered the exchange of material between the two reservoirs. Our findings thus indicate that Jupiter's core reached about 20 Earth masses within less than 1 million years, followed by a more prolonged growth to approximately 50 Earth masses until at least 3–4 million years after Solar System formation. Therefore, Jupiter is confirmed as the oldest planet of the Solar System, with its solid core forming well before the solar nebula gas dissipated, consistent with the core accretion model for giant planet formation.
Quote	Thomas S. Kruijer, Christoph Burkhardt and Gerrit Budde et al. Age of Jupiter inferred from the distinct genetics and formation times of meteorites. Proc Natl Acad Sci USA. 2017. DOI: 10.1073/pnas.1704461114
Element	Molybdenum (Mo)