000004669 001__ 4669 000004669 005__ 20200128115716.0 000004669 0247_ $$2DOI$$a10.1029/2019JE005936 000004669 037__ $$aSCART-2020-0039 000004669 100__ $$aTerasaki, Hidenori 000004669 245__ $$aPressure and composition effects on sound velocity and density of core-forming liquids: Implication to core compositions of terrestrial planets 000004669 260__ $$c2019 000004669 520__ $$aA compositional variety of planetary cores provides insight into their core/mantle evolution and chemistry in the early solar system. To infer core composition from geophysical data, a precise knowledge of elastic properties of core-forming materials is of prime importance. Here, we measure the sound velocity and density of liquid Fe-Ni-S (17 and 30 at% S) and Fe-Ni-Si (29 and 38 at% Si) at high pressures and report the effects of pressure and composition on these properties. Our data show that the addition of sulfur to iron substantially reduces the sound velocity of the alloy and the bulk modulus in the conditions of this study, while adding silicon to iron increases its sound velocity but has almost no effect on the bulk modulus. Based on the obtained elastic properties combined with geodesy data, S or Si content in the core is estimated to 4.6 wt% S or 10.5 wt% Si for Mercury, 9.8 wt% S or 18.3 wt% Si for the Moon, and 32.4 wt% S or 30.3 wt% Si for Mars. In these core compositions, differences in sound velocity profiles between an Fe-Ni-S and Fe-Ni-Si core in Mercury are small, whereas for Mars and the Moon, the differences are substantially larger and could be detected by upcoming seismic sounding missions to those bodies. 000004669 536__ $$a3PRODPLANINT/$$c3PRODPLANINT/$$f3PRODPLANINT 000004669 594__ $$aNO 000004669 6531_ $$aCore 000004669 6531_ $$aLight element 000004669 6531_ $$aElastic property 000004669 6531_ $$aTerrestrial planet 000004669 6531_ $$aHigh pressure 000004669 700__ $$aRivoldini, Attilio 000004669 700__ $$aShimoyama, Yuta 000004669 700__ $$aNishida, Keisuke 000004669 700__ $$aUrakawa, Satoru 000004669 700__ $$aMaki, Mayumi 000004669 700__ $$aKurokawa, Fuyuka 000004669 700__ $$aTakubo, Yusaku 000004669 700__ $$aShibazaki, Yuki 000004669 700__ $$aSakamaki, Tatsuya 000004669 700__ $$aMachida, Akihiko 000004669 700__ $$aHigo, Yuji 000004669 700__ $$aUesugi, Kentaro 000004669 700__ $$aTakeuchi, Akihisa 000004669 700__ $$aWatanuki, Tetsu 000004669 700__ $$aKondo, Tadashi 000004669 773__ $$n8$$pJournal of Geophysical Research: Planets$$v124$$y2019 000004669 8560_ $$fattilio.rivoldini@observatoire.be 000004669 8564_ $$s2122441$$uhttp://publi2-as.oma.be/record/4669/files/Terasaki2019aa01.pdf 000004669 8564_ $$s3922$$uhttp://publi2-as.oma.be/record/4669/files/Terasaki2019aa01.gif?subformat=icon$$xicon 000004669 8564_ $$s6889$$uhttp://publi2-as.oma.be/record/4669/files/Terasaki2019aa01.jpg?subformat=icon-180$$xicon-180 000004669 905__ $$apublished in 000004669 980__ $$aREFERD