Fractional linear polarization as a function of T_bΔΩ for J = 1−0, v₁ = 2⁰ rotational transition (top), and three HCN rotational transitions of the vibrationally excited state (bottom), assuming a magnetic field oriented perpendicular to the direction of propagation of the maser radiation. We considered the magnetic field strength and decay rate listed in Table 3 for HCN. Under these assumptions, the vertical lines set the maximum linear polarization that the different maser lines can reach satisfying the condition gΩ = 10R.