¹Chavrit, D.,¹Moreira, M.A.,²Fike, D.A.,^1,3Moynier, F.
Chemical Geology 520, 52-59 Link to Article [DOI: 10.1016/j.chemgeo.2019.04.025]
¹Université de Paris, Institut de physique du globe de Paris, CNRS, Paris, F-75005, France
²Department of Earth and Planetary Sciences, Washington University, St Louis, MO 63130, United States
³Institut Universitaire de France, Paris, France

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¹Xunyu Zhang,²Meng‐Hua Zhu,¹Roberto Bugiolacchi
Journal of Geophysical Research, Planets (in Press) Link to Article [https://doi.org/10.1029/2018JE005870]
¹Space Science Institute, Macau University of Science and Technology, Macau, China
²Chinese Academy of Sciences Center for Excellence in Comparative Planetology, Hefei, China
Published by arrangement with John Wiley & Sons

The formation of the South Pole‐Aitken (SPA) basin is thought to excavate the deep crust or mantle because of its large size. The pervasive orthopyroxene‐dominated materials found across the basin suggest that they either represent the SPA impact melt or the excavated materials from the lower crust and/or upper mantle. This study analyzes the relative content and distribution of mafic minerals in the SPA area based on the spectra from small fresh craters. The orthopyroxene‐dominated materials in the non‐mare regions are classified into two types based on their distribution and different composition. One is distributed from the center to the edge across the SPA basin and interpreted as the SPA impact melt. The other is Mg‐richer and generally located in some plagioclase‐rich regions (e.g., some large impact craters/basins and the SPA edge), thought to represent materials from the lower crust and/or upper mantle. For the maria in the SPA area, the basaltic materials in the northwest are found to be richer in olivine and/or clinopyroxene than the southern ones.

¹C.T. Unterborn,²W.R. Panero
Journal of Geophysical Research, Planets (in Press) Link to Article [https://doi.org/10.1029/2018JE005844]
¹School of Earth and Space Exploration, Arizona State University
²School of Earth Sciences, The Ohio State University
Published by arrangement with John Wiley & Sons

The interior composition of exoplanets is not observable, limiting our direct knowledge of their structure, composition, and dynamics. Recently described observational trends suggest that rocky exoplanets, that is, planets without significant volatile envelopes, are likely limited to <1.5 Earth radii. We show that given this likely upper limit in the radii of purely‐rocky super‐Earth exoplanets, the maximum expected core‐mantle boundary pressure and adiabatic temperature is relatively moderate, 630 GPa and 5000 K, while the maximum central core pressure varies between 1.5 and 2.5 TPa. We further find that for planets with radii less than 1.5 Earth radii, core‐mantle boundary pressure and adiabatic temperature are mostly a function of planet radius and insensitive to planet structure. The pressures and temperatures of rocky exoplanet interiors, then, are less than those explored in recent shock‐compression experiments, ab‐initio calculations, and planetary dynamical studies. We further show that the extrapolation of relevant equations of state does not introduce significant uncertainties in the structural models of these planets. Mass‐radius models are more sensitive to bulk composition than any uncertainty in the equation of state, even when extrapolated to TPa pressures.