Thin vs. thick disk: left: stars plus stellar remnants; right: luminous stars only. Top: present-day stellar profiles: magenta: total; green: (thick disk); red: thin disk. In all curves, there is an attached best-fit exponential (dashed line of same colour) in the 5−11 kpc range, with scalelengths and column densities at R₀ = 8 kpc as reported in Table 3. Bottom: cumulative fraction of the thin and thick disk masses with respect to the corresponding total disk mass M_disk: M_thin( <r) /M_disk (red curve) and M_thick( <r) /M_disk (green curve) as a function of radius r.