The chemical residue of a white dwarf-dominated galactic halo

Halo initial mass functions (IMFs) heavily biased toward white dwarf (WD) precursors (i.e., similar to 1-8 M.) have been suggested as a suitable mechanism for explaining microlensing statistics along the line of sight to the Large Magellanic Cloud. Such IMFs can apparently be invoked without violating the observed present-day WD luminosity function. By employing a simple chemical evolution argument, we demonstrate that reconciling the observed halo Population II dwarf abundances (i.e., [C, N/O] approximate to -0.5) with that expected from the postulated ''WD-heavy'' IMF (i.e., [C, N/O] greater than or similar to +0.5) is difficult.