Left-hand panel: reduced-χ² of the fit to the BD region (G430M data). Each curve represents a specific value of with values ranging from 12 000 K to 15 000 K, right to left, and for a range of values. The smooth curves are spline fits to the data points (asterisks). Right-hand panel: minima of the curves define the relationship between and , illustrated by the thick line for a Bstr contribution of 55% of the flux in the V-band. Thin lines indicate analogous relationships for other percentage flux contributions (labeled).