The CHNOS elemental budgets of rocky planets are crucial for their structure,
evolution and potential chemical habitability. It is unclear how the nonlocal
disk processes affecting dust in planet-forming disks affect the CHNOS
elemental budgets of nascent planets both inside and outside the Solar System.
We aim to quantify the coupled effect of dynamical and collisional processes on
the initial refractory CHNOS budgets of planetesimals, forming interior to the
water ice line for a Solar and non-Solar composition consistent with the star
HIP 43393. Methods. We utilize the SHAMPOO code to track the effects of
dynamical and collisional processes on 16000 individual dust monomers. Each
monomer is here assigned a refractory chemical composition and mineralogy
informed by the equilibrium condensation code GGCHEM given the P-T conditions
at the initial position of the monomer. Monomers travel embedded in aggregates
through a young class I disk, whose structure is calculated with the ProDiMo
code. Furthermore, monomers are allowed to undergo dehydration and
desulfurization. We find that solid material becomes well-mixed both radially
and vertically. For both the Solar and HIP43393 compositions, the solid phase
in the disk midplane regions interior to r~0.7AU can become enriched in
hydrogen and sulfur by up to 10at% relative to predictions from purely local
calculations. This originates from the inward radial transport of hydrated and
sulfur-bearing minerals such as lizardite and iron sulfide. Nonlocal disk
processing in a young turbulent, massive disk can lead to significant
compositional homogenization of the midplane dust and by extension of the
initial composition of planetesimals. Planetesimals forming at r<0.7AU may become enriched in hydrated minerals and sulfur, which could result in more widespread aqueous alteration interior to the water iceline compared to planetesimals that emerge...

Cet article explore les excursions dans le temps et leurs implications.

Télécharger PDF: