Compared histograms of the Lyα integrated intensity of the observed profiles with those calculated using multi-thread models with hotter outer threads. Left panel: multi-thread models with T₀ values of 30 000 and 15 000 K in the outer threads. Right panel: comparison for somewhat lower temperatures of 15 000 and 10 000 K. The solid black line represents the observed data. Three values of μ are represented with corresponding colours and line-styles.