Figure 1 ,Table 0
    • Figure 1.  (color online) The classification of the solutions. The horizontal and vertical axes denote ${w_2}$ and ${2M'/r_0}$, respectively. The blue curve represents ${2M'/r_0 = (1-2w_2)^{-1}}$, for which ${M=0}$. Each line in the figure is labeled by the text of the same color.