Accretion processes in the early solar system viewed from short-lived radioactive nuclides

Séminaire IPAG de Marc Chaussidon (CRPG, Nancy), jeudi 3 mai 2012 à 11h00, IPAG seminar room

Recent developments of high precision Mg isotopes measurements in meteorites show that short-lived 26Al can be used as a reliable chronometer of condensation, accretion and differentiation processes which took place in the first few million years in the accretion disk around the early Sun. Primitive meteorites contain components (Mg-rich olivines in type I chondrules) which from their Mg and O isotopic compositions could be fragments of planetesimals formed and disrupted early in the disk. These observations are at variance with "classical" ideas on planetesimal formation but are in agreement with recent models which use turbulence to promote streaming instabilities and rapid planetesimal formation.