\(r_e\) decreases with temperature, so \(a=\cfrac{a_e}{r_e}\) increases with temperature.
The minimum point of \(U_{B\,L}+U_{B\,R}\) increases along \(\phi=\cfrac{\pi}{2}\) as the ratio \(\cfrac{a}{r_e}\) increases with increasing temperature, up to \(a\le\approx0.6\). Above \(a\approx0.6\), the value of \(U_B\), first increases then decreases, the value of \(U_B\) at \(a=0.1\) is below the values of \(U_B\) at \(a=0.9\).
\(U_B\) is indicative of the paired electrons ability to hold \(T^{+}\) particles in its \(B\) orbits. At high temperature, the paired electrons is comparatively weak at holding on to the \(T^{+}\), the material in which the paired orbit electrons are part of, releases some of its \(T^{+}\) particles and appears hotter than its ambient temperature.
Have a nice day.
