Contribution functions to the optical depth in the heliospheric model at 0.1 Å from line center (eq. [1]), plotted as a function of the distance from the Sun. The axes are scaled such that the area under the curves gives the total τhw(0.1). The dashed curve is model 1, the dotted curve is model 2, and the dot‐dashed curve is model 3, for comparison with Fig. 2. Comparison with Fig. 2e shows the connection to the elevated temperature structure.