(Y − K_s) vs. K_s CMD with isochrone lines for the helium burning sequence for the same two metallicities and age ranges as Sect. 3.5. Younger, more metal rich (log   (t/yr) = 9.0−9.4, Z = 0.0125) are in blue and the older, more metal poor (log   (t/yr) = 9.4−9.7, Z = 0.0033) are in red. Error bars represent error in LMC distance. Contours are plotted in magenta and green and have the same levels as in Fig. 4. The older population can be seen to be at the 5% contour level.