Condensation temperature (T_c) of Na, plotted against the molar disk C/O (top) and Mg/Si (bottom). Dots represent simulation results based on stellar abundance data for individual stars. Lines represent results for solar abundances with varying C (top) or varying Mg and Si while conserving bulk Mg+Si (bottom). Temperatures are derived from condensation sequence calculations at P = 10⁻⁴ bar.