Figure 2.
Ratio of initial to final Na as a function of mean ρ and |$v$|r. For reference the free fall velocity in this region is |$v$|ff ∼ 108cm s−1. The dashed lines correspond to fixed accretion rates assuming quasi-spherical accretion i.e. |$\rho \approx \dot{M}/(4\pi r^2 v_r)$|. For a range of values Na is enriched by 101.8, so long as |$v$|r is sufficiently low or the ρ is sufficiently high, see text for details.
