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Title: The homogeneous mixing of MgO and H 2 O at extreme conditions

Journal Article · · Contributions to Plasma Physics
 [1];  [1];  [2]
  1. Department of Earth and Planetary Science University of California, Berkeley Berkeley California USA
  2. Department of Earth and Planetary Science University of California, Berkeley Berkeley California USA, Department of Astronomy University of California, Berkeley Berkeley California USA

Abstract Investigating water worlds presents a unique opportunity to understand the fundamental processes of planetary formation and evolution. One key aspect is characterizing the interactions between water and rock under the pressures and temperatures present within these worlds. Investigating the conditions for the homogeneous mixing of these materials is imperative to characterizing bulk properties and evolution of water‐rich exoplanets. Here we use density functional molecular dynamics simulations to study MgO‐H 2 O mixtures at high pressure–temperature conditions where H 2 O occurs in solid, superionic, or liquid form. MgO, the representative rocky material, can be either solid or liquid. We start from 500 K at 120 GPa, increasing the temperature step by step up to 8000 K. By inspection, we determine the temperature at which MgO‐HO homogeneously mix in our simulations. At 6000 K and 174 GPa is when we find the system to homogeneously mix. This heat‐until‐it‐mixes approach provides us with an upper bound on the temperature for the mixing of MgO and H 2 O. We find that homogeneous mixing occurs at sufficiently low temperatures to be relevant for the collisional growth of a water‐rich planet.

Sponsoring Organization:
USDOE
Grant/Contract Number:
DE‐AC52‐07NA27344
OSTI ID:
1983479
Journal Information:
Contributions to Plasma Physics, Journal Name: Contributions to Plasma Physics Vol. 63 Journal Issue: 9-10; ISSN 0863-1042
Publisher:
Wiley Blackwell (John Wiley & Sons)Copyright Statement
Country of Publication:
Germany
Language:
English

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