# Silicate Melting and Vaporization during Rocky Planet Formation

**Authors:** Erik J. Davies, Phil J. Carter, Seth Root, Richard G. Kraus, Dylan K. Spaulding, Sarah T. Stewart, Stein B. Jacobsen$^{4}$  
**arXiv:** [2002.00998](https://arxiv.org/abs/2002.00998)  
**Date:** 2020-02-03  
**Summary page:** https://www.summarizepaper.com/en/paper/2002.00998v1/

## Key points

- Study titled "Silicate Melting and Vaporization during Rocky Planet Formation" by Erik J. Davies et al.
- Investigates impact of collisions inducing melting and vaporization on planet thermal and geochemical evolution
- Highlights lack of understanding on major minerals' thermodynamics under extreme conditions in planet formation
- Conducted experiments at Sandia Z Machine, used forsterite data to calculate specific entropy along Hugoniot curve
- Established critical impact velocities for melting or vaporization upon decompression from shocked state
- Emphasizes significance of initial temperature in influencing vaporization criteria
- Findings applied to $N$-body simulations reveal 20 to 40% mass undergoes processing through collisions exceeding vaporization criteria
- Vaporizing collisions between small bodies crucial in terrestrial planet formation dynamics

## Summary

, , , , 

In their study titled "Silicate Melting and Vaporization during Rocky Planet Formation," Erik J. Davies, Phil J. Carter, Seth Root, Richard G. Kraus, Dylan K. Spaulding, Sarah T. Stewart, and Stein B. Jacobsen$^{4}$ investigate the impact of collisions that induce melting and vaporization on the thermal and geochemical evolution of planets. The authors highlight the lack of understanding regarding the thermodynamics of major minerals under extreme conditions experienced during planet formation. To address this gap in knowledge, the researchers conducted experiments at the Sandia Z Machine and utilized published thermodynamic data for forsterite (Mg$_2$SiO$_4$), a major mineral, to calculate specific entropy in the liquid phase along the principal Hugoniot curve. By determining the specific entropy of shocked forsterite and revising entropies for shocked silica, they were able to establish critical impact velocities required for melting or vaporization upon decompression from a shocked state to 1 bar pressure and triple points near solar nebula pressures. Moreover, the study emphasizes the significance of initial temperature in influencing vaporization criteria. Applying their findings to $N$-body simulations of terrestrial planet formation, the authors discovered that a substantial portion (20 to 40%) of total system mass undergoes processing through collisions exceeding incipient vaporization criteria at triple points. Overall, this research sheds light on how vaporizing collisions between small bodies play a crucial role in terrestrial planet formation processes. The insights gained from this study contribute valuable information towards understanding planetary evolution dynamics under extreme conditions during rocky planet formation.