Top row left: Bi-dimensional probability density in the β vs. age plane, marginalized with respect to initial helium and metallicity for scenario A. Middle: as inthe left panel but for scenario B. Right: as in the left panel but for scenario C. Bottom row:as in the top row but for scenarios A_M, B_M, and C_M. The crosses mark the reference β and age values for all six cases. The little island of non-null density in the middle panel of the top row, and those in the middle and right panels of the bottom row, are numerical artefacts.