EW of FeKα against L_{1−10 keV}. γ Cassiopeae analogues (circles) lie at L_{1−10 keV}< 10³³ erg/s. Open symbols indicate that either the distance or the error in the estimation of the distance is unknown. The solid line corresponds to a linear fit on logarithmic scale of the filled diamonds, that is, the sources with available distance with error estimation and L_{1−10 keV}> 10³³ erg/s.