Thermal electron relativistic threshold
= Thermal electron relativistic threshold
{title2=$T_*=m_ec^2/k_B$}
In a dilute <Electron> gas, thermal kinetic energies become relativistic near $k_BT=m_ec^2$, corresponding to $T_*\simeq5.93\times10^9\,\mathrm K$. This is a crossover in the momentum distribution, not an abrupt <temperature> transition. Degenerate <Electrons> can instead be relativistic at much lower <temperature> if their <Fermi momentum> exceeds $m_ec$.