Upper panel: ternary plot with posterior distribution of the mass fractional composition with three representative components: MgSiO₃, Fe, and C (graphitic carbon). This three-dimensional space is plotted in a 2D ternary landscape because the sum of the contributions equals one. The 1 and 2σ contours are indicated with red and dark red lines, respectively. Lower panel: 1D posterior distribution of the relative masses of MgSiO₃, Fe, and graphitic carbon. The Fe content is bounded from below and above, x(Fe) = 0.35 ± 0.07, while an unconstrained ratio mix of C and MgSiO₃ makes up the rest.