Left panel: M₂ vs. M₁ relationships for different inclination i of the system orbital plane obtained from the mass function . The inclination range is of 65°−90° with a step of 5° from top to bottom. The solid-line corresponds to a companions mass ratio of q = 0.165. Main-sequence stars with T_eff = 24   000 K are located to the left from the dotted-line. Right panel: a Hertzsprung-Russell diagram with recent determinations of fundamental parameters of π Aqr. Solid lines show evolutionary tracks of stars with rotation from Ekström et al. (2012). Initial masses are indicated by numbers at the corresponding track. Filled circles show the positions based on the luminosity calculated using the two Hipparcos distances (see text), the diamond shows data from Hohle et al. (2010), and the filled square shows parameters adopted here.