Pressure and Composition Effects on Sound Velocity and Density of Core-Forming Liquids: Implication to Core Compositions of Terrestrial Planets

Hidenori Terasaki, Attilio Rivoldini, Yuta Shimoyama, Keisuke Nishida, Satoru Urakawa, Mayumi Maki, Fuyuka Kurokawa, Yusaku Takubo, Yuki Shibazaki, Tatsuya Sakamaki, Akihiko Machida, Yuji Higo, Kentaro Uesugi, Akihisa Takeuchi, Tetsu Watanuki, Tadashi Kondo

Research output: Contribution to journalArticle

Abstract

A compositional variety of planetary cores provides insight into their core/mantle evolution and chemistry in the early solar system. To infer core composition from geophysical data, a precise knowledge of elastic properties of core-forming materials is of prime importance. Here, we measure the sound velocity and density of liquid Fe-Ni-S (17 and 30 at% S) and Fe-Ni-Si (29 and 38 at% Si) at high pressures and report the effects of pressure and composition on these properties. Our data show that the addition of sulfur to iron substantially reduces the sound velocity of the alloy and the bulk modulus in the conditions of this study, while adding silicon to iron increases its sound velocity but has almost no effect on the bulk modulus. Based on the obtained elastic properties combined with geodesy data, S or Si content in the core is estimated to 4.6 wt% S or 10.5 wt% Si for Mercury, 9.8 wt% S or 18.3 wt% Si for the Moon, and 32.4 wt% S or 30.3 wt% Si for Mars. In these core compositions, differences in sound velocity profiles between an Fe-Ni-S and Fe-Ni-Si core in Mercury are small, whereas for Mars and the Moon, the differences are substantially larger and could be detected by upcoming seismic sounding missions to those bodies.

Original languageEnglish
JournalJournal of Geophysical Research: Planets
DOIs
Publication statusAccepted/In press - Jan 1 2019

Fingerprint

Composition effects
sound velocity
terrestrial planets
Pressure effects
Acoustic wave velocity
Planets
pressure effects
acoustic velocity
planet
liquid
liquids
bulk modulus
elastic property
Moon
Liquids
Chemical analysis
Mercury
mercury
Mars
Iron

Keywords

  • core
  • elastic property
  • high pressure
  • light element
  • terrestrial planet

ASJC Scopus subject areas

  • Geophysics
  • Forestry
  • Oceanography
  • Aquatic Science
  • Ecology
  • Water Science and Technology
  • Soil Science
  • Geochemistry and Petrology
  • Earth-Surface Processes
  • Atmospheric Science
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science
  • Palaeontology

Cite this

Pressure and Composition Effects on Sound Velocity and Density of Core-Forming Liquids : Implication to Core Compositions of Terrestrial Planets. / Terasaki, Hidenori; Rivoldini, Attilio; Shimoyama, Yuta; Nishida, Keisuke; Urakawa, Satoru; Maki, Mayumi; Kurokawa, Fuyuka; Takubo, Yusaku; Shibazaki, Yuki; Sakamaki, Tatsuya; Machida, Akihiko; Higo, Yuji; Uesugi, Kentaro; Takeuchi, Akihisa; Watanuki, Tetsu; Kondo, Tadashi.

In: Journal of Geophysical Research: Planets, 01.01.2019.

Research output: Contribution to journalArticle

Terasaki, H, Rivoldini, A, Shimoyama, Y, Nishida, K, Urakawa, S, Maki, M, Kurokawa, F, Takubo, Y, Shibazaki, Y, Sakamaki, T, Machida, A, Higo, Y, Uesugi, K, Takeuchi, A, Watanuki, T & Kondo, T 2019, 'Pressure and Composition Effects on Sound Velocity and Density of Core-Forming Liquids: Implication to Core Compositions of Terrestrial Planets', Journal of Geophysical Research: Planets. https://doi.org/10.1029/2019JE005936
Terasaki, Hidenori ; Rivoldini, Attilio ; Shimoyama, Yuta ; Nishida, Keisuke ; Urakawa, Satoru ; Maki, Mayumi ; Kurokawa, Fuyuka ; Takubo, Yusaku ; Shibazaki, Yuki ; Sakamaki, Tatsuya ; Machida, Akihiko ; Higo, Yuji ; Uesugi, Kentaro ; Takeuchi, Akihisa ; Watanuki, Tetsu ; Kondo, Tadashi. / Pressure and Composition Effects on Sound Velocity and Density of Core-Forming Liquids : Implication to Core Compositions of Terrestrial Planets. In: Journal of Geophysical Research: Planets. 2019.
@article{4fc77794fe80445a8b7961e750f42123,
title = "Pressure and Composition Effects on Sound Velocity and Density of Core-Forming Liquids: Implication to Core Compositions of Terrestrial Planets",
abstract = "A compositional variety of planetary cores provides insight into their core/mantle evolution and chemistry in the early solar system. To infer core composition from geophysical data, a precise knowledge of elastic properties of core-forming materials is of prime importance. Here, we measure the sound velocity and density of liquid Fe-Ni-S (17 and 30 at{\%} S) and Fe-Ni-Si (29 and 38 at{\%} Si) at high pressures and report the effects of pressure and composition on these properties. Our data show that the addition of sulfur to iron substantially reduces the sound velocity of the alloy and the bulk modulus in the conditions of this study, while adding silicon to iron increases its sound velocity but has almost no effect on the bulk modulus. Based on the obtained elastic properties combined with geodesy data, S or Si content in the core is estimated to 4.6 wt{\%} S or 10.5 wt{\%} Si for Mercury, 9.8 wt{\%} S or 18.3 wt{\%} Si for the Moon, and 32.4 wt{\%} S or 30.3 wt{\%} Si for Mars. In these core compositions, differences in sound velocity profiles between an Fe-Ni-S and Fe-Ni-Si core in Mercury are small, whereas for Mars and the Moon, the differences are substantially larger and could be detected by upcoming seismic sounding missions to those bodies.",
keywords = "core, elastic property, high pressure, light element, terrestrial planet",
author = "Hidenori Terasaki and Attilio Rivoldini and Yuta Shimoyama and Keisuke Nishida and Satoru Urakawa and Mayumi Maki and Fuyuka Kurokawa and Yusaku Takubo and Yuki Shibazaki and Tatsuya Sakamaki and Akihiko Machida and Yuji Higo and Kentaro Uesugi and Akihisa Takeuchi and Tetsu Watanuki and Tadashi Kondo",
year = "2019",
month = "1",
day = "1",
doi = "10.1029/2019JE005936",
language = "English",
journal = "Journal of Geophysical Research",
issn = "0148-0227",
publisher = "American Geophysical Union",

}

TY - JOUR

T1 - Pressure and Composition Effects on Sound Velocity and Density of Core-Forming Liquids

T2 - Implication to Core Compositions of Terrestrial Planets

AU - Terasaki, Hidenori

AU - Rivoldini, Attilio

AU - Shimoyama, Yuta

AU - Nishida, Keisuke

AU - Urakawa, Satoru

AU - Maki, Mayumi

AU - Kurokawa, Fuyuka

AU - Takubo, Yusaku

AU - Shibazaki, Yuki

AU - Sakamaki, Tatsuya

AU - Machida, Akihiko

AU - Higo, Yuji

AU - Uesugi, Kentaro

AU - Takeuchi, Akihisa

AU - Watanuki, Tetsu

AU - Kondo, Tadashi

PY - 2019/1/1

Y1 - 2019/1/1

N2 - A compositional variety of planetary cores provides insight into their core/mantle evolution and chemistry in the early solar system. To infer core composition from geophysical data, a precise knowledge of elastic properties of core-forming materials is of prime importance. Here, we measure the sound velocity and density of liquid Fe-Ni-S (17 and 30 at% S) and Fe-Ni-Si (29 and 38 at% Si) at high pressures and report the effects of pressure and composition on these properties. Our data show that the addition of sulfur to iron substantially reduces the sound velocity of the alloy and the bulk modulus in the conditions of this study, while adding silicon to iron increases its sound velocity but has almost no effect on the bulk modulus. Based on the obtained elastic properties combined with geodesy data, S or Si content in the core is estimated to 4.6 wt% S or 10.5 wt% Si for Mercury, 9.8 wt% S or 18.3 wt% Si for the Moon, and 32.4 wt% S or 30.3 wt% Si for Mars. In these core compositions, differences in sound velocity profiles between an Fe-Ni-S and Fe-Ni-Si core in Mercury are small, whereas for Mars and the Moon, the differences are substantially larger and could be detected by upcoming seismic sounding missions to those bodies.

AB - A compositional variety of planetary cores provides insight into their core/mantle evolution and chemistry in the early solar system. To infer core composition from geophysical data, a precise knowledge of elastic properties of core-forming materials is of prime importance. Here, we measure the sound velocity and density of liquid Fe-Ni-S (17 and 30 at% S) and Fe-Ni-Si (29 and 38 at% Si) at high pressures and report the effects of pressure and composition on these properties. Our data show that the addition of sulfur to iron substantially reduces the sound velocity of the alloy and the bulk modulus in the conditions of this study, while adding silicon to iron increases its sound velocity but has almost no effect on the bulk modulus. Based on the obtained elastic properties combined with geodesy data, S or Si content in the core is estimated to 4.6 wt% S or 10.5 wt% Si for Mercury, 9.8 wt% S or 18.3 wt% Si for the Moon, and 32.4 wt% S or 30.3 wt% Si for Mars. In these core compositions, differences in sound velocity profiles between an Fe-Ni-S and Fe-Ni-Si core in Mercury are small, whereas for Mars and the Moon, the differences are substantially larger and could be detected by upcoming seismic sounding missions to those bodies.

KW - core

KW - elastic property

KW - high pressure

KW - light element

KW - terrestrial planet

UR - http://www.scopus.com/inward/record.url?scp=85071329758&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85071329758&partnerID=8YFLogxK

U2 - 10.1029/2019JE005936

DO - 10.1029/2019JE005936

M3 - Article

AN - SCOPUS:85071329758

JO - Journal of Geophysical Research

JF - Journal of Geophysical Research

SN - 0148-0227

ER -