Formation of the binary and hypothesised evolution of the binary components and planetary material. R_p is the projected separation between the binary components, and r_crit is the critical initial semi major axis that a planetesimal must have in order to survive through the stellar evolution to the WD phase assuming an eccentricity of zero. The depletion of moderate refractory relative to refractory elements in (B), indicated by red arrows, can occur both during and after nebula condensation. The different colors of the planetesimals represent whether they have experienced depletion of mildly refractory elements (brown) or not (gray). The WD is being observed in declining phase (G). Equations in phases (E) to (G) show how the relative abundances of elements X₁ and X₂ change from the parent body depending on the accretion phase.