The parameterization of solid metal‐liquid metal partitioning of siderophile elements

Abstract— Many solar system processes involve a metallic liquid, and the composition of the metallic liquid, such as the liquid's concentrations of S, P, and C, will influence the partitioning of elements during such processes. We present a method for parameterizing solid metal‐liquid metal partition coefficients for siderophile (metal‐loving) elements as a function of the metallic liquid composition. Our parameterization method is based on an older theory of Jones and Malvin (1990), which stated that the metallic liquid is composed of metal and non‐metal‐bearing domains, and the domains are the dominant influence on the partitioning behavior. By revising the means by which the metal domains are calculated, our revised parameterization method is able to match experimental partitioning data from the Fe‐Ni‐S, Fe‐Ni‐P, Fe‐Ni‐S‐P, and Fe‐Ni‐C systems. Mathematical expressions were derived for the solid metal‐liquid metal partitioning of 13 siderophile elements. Elements that are chalcophile (S‐loving), P‐loving, or C‐loving prefer the non‐metal‐bearing domains in the metallic liquid and, consequently, aren't fit by the parameterization method presented here. Possible applications for our parameterization method include modeling the crystallization of iron meteorites, planetary differentiation, and the solidification of Earth's inner core.     

Mercury's spectrophotometric properties: Update from the Mercury Dual Imaging System observations during the third MESSENGER flyby

Presented here are analyses of the photometric measurements acquired by the imaging system on the MESSENGER spacecraft during its three flybys of Mercury, in particular the dedicated sequence of photometric measurements obtained during the third flyby. A concise, analytical approach is adopted for characterizing the effects of scattered light on the images. This approach works well for wavelengths shorter than 700 nm but breaks down at the longer wavelengths where the scattering behavior of the imaging system is more complex. Broadband spectral properties are commensurate with ground-based observations for spectra acquired at phase angles less than 110°; photometric corrections to a common illumination and viewing geometry provide consistent results for those phase angles. No phase reddening is apparent in the image-derived spectra. A bolometric albedo of 0.081 is derived over the wavelength range of the imaging system.     

Differentiation of clay resources on a limestone plain: The analysis of clay utilization during the Maya Formative at K'axob Belize

Differentiating clay resources in a uniform limestone plain, such as occurs in northern Belize, offers special challenges for the archaeologist. Combining data from soil mapping with petrographic and neutron activation analysis provides a mechanism for distinguishing possible resource areas. This study employed each of these differing avenues of analysis to determine possible clay resource areas used during the Maya Formative in northern Belize Central America. The results indicate that clay usage changed significantly from the Middle Formative period to the end of Late Formative period. These changes suggest a move to increased localized production and resource exploitation by the end of the period. © 2000 John Wiley & Sons, Inc.     

Ob-Stars on the utmost Borders of M 31

In a field of 4 square degrees, including the southwestern part of M 31 18 blue starlike objects are found by a photometric statistics in U,B,V of all starlike objects in this field. With great probability 13 of them are OB stars of M 31. Their utmost distances from the nucleus of M 31 are 35…50 kpc. Three further objects are probably quasistellar objects. Two others are striking by their extraordinary position in the two-colour diagram and cannot be classified in a distinct category of objects.