The area |$A$| of a common marginally DTTS in a Majumdar–Papapetrou spacetime as a function of |$z_0/m$|⁠. The cases of two kinds of normalizations are shown. One is |$A/4\pi r_{\rm DTTS+}^2$| and the other is |$A/4\pi r_p^2$|⁠. See text for details.