Fig. 1: A comparison of bulk planet (core + crust + mantle) compositions.
From: Polluted white dwarfs reveal exotic mantle rock types on exoplanets in our solar neighborhood
Bulk compositions of polluted white dwarfs (PWDs) are compared to the bulk planets Earth21, Moon23, and Mars26 and FGKM stars of the Hypatia Catalog17 (a, b), and various meteorite types19 (c), as well as rocks from Earth31, Moon32, and Mars30, and iron and stony iron meteorites19 (d). c also shows the field for the subclass of achondrites known as urelites, which have an unknown parentage. Mg + Si + Ca + Fe are normalized to equal 100%. Vertical and horizontal lines labeled “WD Unc.” show the propagated average uncertainties of PWD compositions. a, b show that PWDs exhibit a much wider range of compositions than that found among FGKM stars. c, d show that PWDs overlap only imperfectly with meteorites from our Solar System, and almost not at all with rocks from Earth, Mars, or Moon. WD1041 + 092 has the highest Ca among our PWDs, but as can be seen in d, it cannot be a candidate for continental crust as it is far removed from granitic rocks that characterize such crust types. MORB Mid-Ocean Ridge Basalt.
