Vous êtes ici : Accueil / Séminaires / Séminaires passés / 2013-2014 / 16/12 Alessandro Morbidelli - "The age of the Moon" ENS ampli L

16/12 Alessandro Morbidelli - "The age of the Moon" ENS ampli L

Quand ? Le 16/12/2013,
de 14:00 à 15:55
Ajouter un événement au calendrier vCal
iCal

According to the generally accepted scenario, the last giant impact on the Earth formed the Moon and initiated the final phase of core formation by melting the Earth’s mantle. A key goal of geochemistry is to date this event, but different model ages have been proposed. Some argue for an early Moon-forming event, 30 My after the condensation of the first solids, while others claim a date later than 50 My and possibly as late as ~100 My. We use a large number of N-body simulations to demonstrate a relationship between the time of the last giant impact on Earth-like planets and the subsequent mass accreted, called the late veneer. As the time of the last giant impact increases, the mass of the late veneer decreases in a quantitatively predictable fashion. This relationship is model-independent and holds across a large number of initial disc and dynamical conditions. The mass of the late veneer – or at least an upper limit on the mass – is constrained by the abundance of the highly siderophile elements in the Earth's mantle. We use current measurements to determine a range of plausible Moon formation ages. Only certain initial and dynamical conditions produce giant impacts in the determined age-range and match simultaneously other constraints such as the rapid (2 My) formation of Mars.

Actions sur le document

LogoENS.gif

Département ENS
  • Directeur :
    Stéphane Labrosse
  • Secrétaire :
    Emmanuelle Lousson
« Mars 2017 »
Mars
LuMaMeJeVeSaDi
12345
6789101112
13141516171819
20212223242526
2728293031
 

Outils personnels