Model of the mineralogy of the deep interior of Triton

Abstract

Triton, the largest satellite of Neptune, is one of the most fascinating icy moons in the outer Solar System, with an origin that likely extends to the Kuiper Belt. Like other icy satellites, the mineralogical composition of Triton's deep interior is a function of its evolutionary path. In this work, we use the open- access Perple_X software to model the evolutionary paths, anhydrous and hydrous, describing three different mineralogical models to investigate the possible mineral composition forming the rocky fraction of Triton's deep interior. We modelled the phase assemblages adopting three carbonaceous chondrites (Orgueil, Murchison, Allende) as precursor material of the proto-Triton. We found that Triton's deep interior could have evolved during its history into three possible mineral assemblages: an anhydrous deep interior rich in olivine and pyroxenes, a hydrous deep interior rich in hydrated silicates, and a dehydrated deep interior rich in hydrated silicates (amphiboles and chlorite), olivine and pyroxenes. We show that future measurement of the gravity field of Triton can be used to determine the present mineral assemblages of its deep interior.