Thermal equation of state of ε-Fe at exoplanetary interior conditions

ORAL

Abstract

The equation of state (EoS) of hcp-iron (ε-Fe) is essential for investigating physical properties of planetary cores. Despite its importance to geophysics and planetary astronomy, experimental investigations of ε-Fe at relevant conditions are still challenging. Therefore, ab initio calculations can contribute decisively to elucidating the equation of state (EoS) and other properties of this system. In this study, we present ab initio results of the properties of ε-Fe covering a wide range of pressures (0 - 1,400 GPa) and temperatures (300 - 8,000 K). Two new techniques are employed: i) a PAW dataset for iron specially designed for very high-pressure calculations [1], and ii) a free energy calculation approach based on the phonon gas model compatible with temperature dependent phonon frequencies, here produced by thermal electronic excitations. These new features of the calculation produce an isentropic EoS in good agreement with data from recent ramp compression experiments up to 1,400 GPa conducted at the National Ignition Facility (NIF)[2].
1. K. Sarkar et al., J. Comp. Phys.347,39-55 (2017)
2. R. F. Smith et al., Nature Astronomy. 2, 452–458 (2018)

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Presenters

  • Jingyi Zhuang

    Department of Applied Physics and Applied Mathematics, Columbia University in the City of New York, 500 W. 120th St., Mudd 200, MC 4701 New York, NY 10027, USA, Department of Applied Physics and Applied Mathematics, Columbia University in the City of New York, 500 W. 120th St., Mudd 200, MC 4701 New York, NY 10027, USA.

Authors

  • Jingyi Zhuang

    Department of Applied Physics and Applied Mathematics, Columbia University in the City of New York, 500 W. 120th St., Mudd 200, MC 4701 New York, NY 10027, USA, Department of Applied Physics and Applied Mathematics, Columbia University in the City of New York, 500 W. 120th St., Mudd 200, MC 4701 New York, NY 10027, USA.

  • Hongjin Wang

    Department of Applied Physics and Applied Mathematics, Columbia University in the City of New York, 500 W. 120th St., Mudd 200, MC 4701 New York, NY 10027, USA, Department of Applied Physics and Applied Mathematics, Columbia University in the City of New York, 500 W. 120th St., Mudd 200, MC 4701 New York, NY 10027, USA.

  • Qi Zhang

    Department of Applied Physics and Applied Mathematics, Columbia University in the City of New York, Department of Applied Physics and Applied Mathematics, Columbia University in the City of New York, 500 W. 120th St., Mudd 200, MC 4701 New York, NY 10027, USA, Department of Applied Physics and Applied Mathematics, Columbia University in the City of New York, 500 W. 120th St., Mudd 200, MC 4701 New York, NY 10027, USA.

  • Kanchan Sarkar

    Department of Earth and Environmental Sciences, Lamont-Doherty Earth Observatory (LDEO), and Applied Physics and Applied Mathematics (APAM), Columbia University in the City o, Department of Applied Physics and Applied Mathematics, Columbia University in the City of New York, 500 W. 120th St., Mudd 200, MC 4701 New York, NY 10027, USA

  • Renata Wentzcovitch

    Department of Applied Physics and Applied Mathematics, Columbia University in the City of New York, Department of Earth and Environmental Sciences, Lamont-Doherty Earth Observatory (LDEO), and Applied Physics and Applied Mathematics (APAM), Columbia University in the City o, Department of Applied Physics and Applied Mathematics, Department of Earth and Environmental Sciences, Lamont-Doherty Earth Observatory, Columbia University, Columbia University, Department of Applied Physics and Applied Mathematics, Columbia University, Applied Physics and Applied Mathematics and Department of Earth and Environmental Sciences, Lamont Doherty Earth Observatory, Columbia University, Department of Applied Physics and Applied Mathematics, Columbia University in the City of New York, 500 W. 120th St., Mudd 200, MC 4701 New York, NY 10027, USA, Department of Applied Physics and Applied Mathematics, Columbia University in the City of New York, 500 W. 120th St., Mudd 200, MC 4701 New York, NY 10027, USA., Department of Applied Physics and Applied Mathematics; Department of Earth and Environmental Sciences and Lamont-Doherty Earth Observatory, Columbia University, 10027, USA