Parameter space of the age-circularity priors for Au-6-60-5. We use three parameters to determine the λ_z−t prior, including the age when λ_z = 0, the age when λ_z = 1, and the dispersion σ_k. The largest orange triangles denote the model with the minimum χ², and the other coloured dots represent the models within the 1σ confidence level, as indicated by the colour bar. The small black asterisks represent the models outside the 1σ confidence level.