Explaining Mercury's Density through Magnetic Erosion

Abstract

In protoplanetary disks, dust grains rich in metallic iron can attract each other magnetically. If they are magnetized to values near saturation, the magnetically induced collision speeds are high enough to knock off the non-magnetized, loosely bound silicates. This process enriches the surviving portions of the dust grains in metallic iron, which further enhances the magnetically mediated collisions. The magnetic enhancement to the collisional cross-section between the iron rich dust results in rapid grain growth leading to planetesimal formation. While this process of knocking off silicates, which we term "magnetic erosion", occurs only in a very limited portion of a protoplanetary disk, it is a possible explanation for Mercury's disproportionately large iron core.

8 pages, 2 figures, accepted, Icarus

References in corpus (18)

• Interstellar Dust Grains
• Rapid planetesimal formation in turbulent circumstellar discs
• The outcome of protoplanetary dust growth: pebbles, boulders, or planetesimals? I. Mapping the zoo of laboratory collision experiments
• Electric charging of dust aggregates and its effect on dust coagulation in protoplanetary disks
• On the Evolution of the Snow Line in Protoplanetary Discs
• Turbulence and Steady Flows in 3D Global Stratified MHD Simulations of Accretion Disks
• Equilibrium Condensation from Chondritic Porous IDP Enriched Vapor: Implications for Mercury and Enstatite Chondrite Origins
• Turbulence-Induced Relative Velocity of Dust Particles I: Identical Particles
• Photophoretic separation of metals and silicates: the formation of Mercury like planets and metal depletion in chondrites
• Charging and coagulation of dust in protoplanetary plasma environments
• Magnetic Aggregation I: Aggregation Dynamics and Numerical Modelling
• Mineral Processing by Short Circuits in Protoplanetary Disks
• Short Circuits in Thermally Ionized Plasmas: A Mechanism for Intermittent Heating of Protoplanetary Disks
• On the evolution of the snow line in protoplanetary discs II: Analytic approximations
• The implications of particle rotation on the effect of photophoresis
• Turbulence Induced Collision Velocities and Rates between Different Sized Dust Grains
• Turbulence induced collisional velocities and density enhancements: large inertial range results from shell models
• Grain charging in protoplanetary discs

Cited by in corpus (13)

• Understanding planet formation using microgravity experiments
• Nucleation and growth of iron pebbles explains the formation of iron-rich planets akin to Mercury
• HD 23472: A multi-planetary system with three super-Earths and two potential super-Mercuries
• The Elusive Origin of Mercury
• Seeding the Formation of Mercurys: An Iron-sensitive Bouncing Barrier in Disk Magnetic Fields
• Forming super-Mercuries: The role of stellar abundances
• Composition and Size Dependent Sorting in Preplanetary Growth: Seeding the Formation of Mercury-like Planets
• The HD 137496 system: A dense, hot super-Mercury and a cold Jupiter
• Dynamical avenues for Mercury's origin II: in-situ formation in the inner terrestrial disk
• The Exosphere as a Boundary: Origin and Evolution of Airless Bodies in the Inner Solar System and Beyond Including Planets with Silicate Atmospheres
• Ferromagnetism and particle collisions: applications to protoplanetary disks and the meteoritical record
• The Curie line in protoplanetary disks and the formation of Mercury-like planets
• Selective Aggregation Experiments on Planetesimal Formation and Mercury-Like Planets