Correlation between p_B and ξr_B + m_B in the unsaturated regime for p_L = 2 (black line) and p_L = 3 (dotted). Here, η = 4 and ξ = 0.9. In dark gray: excluded region. In red: exponents corresponding to mass losses outside the envelope of Wood et al. (2005) data. In green: exponents consistent with the mass-loss constraints. The light gray band corresponds to the upper and lower bounds from ZDI statistical studies (see Sect. 3.4 for more details).