¹Megan D. Mouser, ¹Yingwei Fei
Meteoritics & Planetary Science (in Press)
Link to Article [DOI: 10.1111/maps.70230]
¹Amentum, Astromaterials Research and Exploration Science (ARES) Division, NASA Johnson Space Center, Houston, TX, USA

Published by arrangement with John Wiley & Sons

Early terrestrial planetary formation processes included melting of chondritic material, leading to differentiation of small planetary bodies. The differentiation process may have been different for various sized objects in the solar system, where some may have gone through total melting (i.e., magma ocean) to form a core and silicate mantle, while others may have experienced partial melting that modified and differentiated the planetary embryo to varying degrees. Based on evidence of differentiated meteorite specimens and spectroscope evidence of silicate and metal asteroids, differentiated planetary bodies are common in the solar system. This work experimentally explores the partial melting process and how that could lead to core formation on a planetary embryo with internal pressures up to 5 GPa. We identified an efficient mechanism to mobilize metal materials when the silicate matrix reached ≥20% partial melting at pressures >3 GPa that usually disrupt interconnected metallic melt because of the large dihedral angle. The predicted percolative velocity of these metallic blebs would be fast enough to percolate toward the center of a smaller planetary body within a few million years while heat from the decay of short-lived radioisotopes is still prevalent.