Kerr-Newman horizon temperature
= Kerr-Newman horizon temperature
{c}
{title2=$T_H=(r_+-r_-)/(4\pi(r_+^2+a^2))$}
The outer-horizon <surface gravity> is $(r_+-r_-)/(2(r_+^2+a^2))$. <Hawking radiation> or nondegenerate <Euclidean black-hole regularity condition> gives $T_H=\kappa/(2\pi)$ in units $G=\hbar=c=k_B=1$. The zero-temperature extremal value is the nonextremal limit; conical regularity alone does not fix a Euclidean period at a degenerate horizon.