Core-mantle coupled numerical modeling of Mercury’s thermal evolution

doi:10.7523/j.ucas.2023.062

Abstract

Abstract: Thermal evolution is at the origin of all dynamics inside a planet. In terms of approximations including parameterizing the stagnant-lid convection heat transfer in Mercury’s mantle and representing the temperature distribution in Mercury’s liquid core by an adiabat, a one-dimensional finite difference model with core-mantle coupling is established in this study to investigate Mercury’s thermal evolution since its core began to solidify. Based on observational data and previous research, this article focuses on analyzing the influence of the solidification mode of Mercury’s core and the radioactive heat generation in Mercury’s mantle on the internal temperature and heat flow evolution of Mercury, laying a foundation for studying the origin of Mercury’s magnetic field. The numerical modeling results indicate that the thermal evolution of outward solidification of Mercury’s core cannot explain the observed magnetic field of Mercury. Based on a previous estimate of the thickness of a stable conductive layer in the upper region of Mercury’s core, the thermal evolution model with inward core solidification predicts that the current solid outer core of Mercury has an age older than 2.8 Ga, while the heat flow through the current liquid inner core of Mercury is between 0.8 and 0.4 TW. The low intensity of the observed Mercury’s magnetic field is a combined result of the low heat flow through the liquid inner core and the magnetic shielding effect of the solid outer core.

Key words: planetary physics, Mercury, thermal evolution, core-mantle coupling, origin of magnetic field

CLC Number:

P185.1

ZHAN Wenzhen, YU Hongzheng, WANG Shimin. Core-mantle coupled numerical modeling of Mercury’s thermal evolution[J]. Journal of University of Chinese Academy of Sciences, 2025, 42(3): 421-432.

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