A large proto-Mercury as the aubrite parent body |
Auteur | Cartier Camille |
Institution | Centre de Recherches Pétrographiques et Géochimiques (Nancy) |
Theme | Theme5 |
| Auteur(s) supplémentaire(s) | Charlier B., Boyet M., Spalding C., Namur O. |
| Institution(s) supplémentaire(s) | University of Liège, Université Clermont Auvergne, Princeton University, KU Leuven |
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Abstract | Aubrite meteorites are ancient achondrites formed under reduced conditions in the silicate portion of a differentiated planetary object whose chemical and physical properties are unknown. Here we use Ni and Co partitioning between metal and silicate to estimate the pressure and oxygen fugacity (fO2) conditions of core formation in the aubrite parent body (AuPB). Our model indicates an fO2 of IW-5.2 (-1.8 +1.4) and a pressure of 29 (-21 +32) GPa, suggesting a highly reduced and planetary-sized (0.3 - 0.8 Earth mass) AuPB , consistent with a large proto-Mercury. The chemical continuum observed between Mercury’s surface and aubrites supports that proto-Mercury was the AuPB whose mantle was stripped-off by impact. Relict debris from proto-Mercury may have partly accreted to outer terrestrial planets and currently form E-type asteroids, the actual source of aubrites. |
