A numerical approach using a finite element model to constrain the possible interior layout of (16) Psyche

TL;DR

This study uses a finite element model to numerically constrain the interior structure of asteroid (16) Psyche, suggesting a metallic core and layered silicate regions, based on density and pressure constraints.

Contribution

It introduces an inverse problem algorithm combining finite element modeling and pressure constraints to determine Psyche's interior layout, considering various layer configurations.

Findings

Smallest core radius likely 72 km

Silicate-rich layer up to 68 km thick

Core may occupy 34-40% of Psyche's size

Abstract

Asteroid (16) Psyche is notable for the largest M-type asteroid and has the high radar albedo among the main-belt asteroids. The object is likely a mixture of metal and silicates because of its lower bulk density than metallic materials and observations inferring the existence of silicate materials on the surface. Here, we numerically investigate the interior layout when the structure of Psyche consists of a spherical iron core and two types of silicate-rich layers (compressed and uncompressed ones resulting from the compaction process. We develop an inverse problem algorithm to determine the layout distribution by combining a Finite Element Model approach that accounts for density variations and constrains pressure-based crushing conditions. The results show that given the crushing limit of 10 MPa the smallest core size likely reaches 72 km in radius, and the silicate-rich layer, consisting of both compressed and uncompressed regions, has a thickness ranging up to 68 km. To support the localized metal concentration at the crater-like region detected in the recent radar observation, we give more constraints on the minimum core size which takes up to 34 - 40 % of the entire size of Psyche. Our study also addresses that the ferrovolcanic surface eruptions could still be a source of metal-rich materials. Finally, while the differentiated structure having a spherical core condition is just part of potential scenarios, the present study infers that the core and compressed layer conditions likely control the surface condition.