High-temperature corrections for the classical expressions of radiative losses from a black body

The contribution from thermally generated electron-positron pairs to the ra diative losses from a black body is considered near the temperature corresp onding to the electron's rest mass energy T-c = m(e)c(2)/k. The correction factors are defined as the ratio of corrected expressions (which also inclu de the contribution from thermal pairs) to the classical expressions (which include merely photons). The correction factors for energy, free energy, a nd entropy fluxes have different values about 0.5T(c), while they have the same value at T much less than T-c and T much greater than T-c. The Stephan -Boltzmann's constant becomes temperature dependent due to the contribution of thermal pairs. According to the classical expressions of radiative loss es, the ratio of energy flux to the absolute value of free energy flux is a constant and it is equal to 3. On the contrary, it is shown that it is a f unction of temperature about T-c and it has a maximum about 0.38T(c). The c orrection factor for mean energy per emitted thermal particle has also a ma ximum about T=0.42T(c).