 Stellar energy balance equation

For a slowly evolving spherical star, the Lagrangian energy equation separates nuclear rest-mass release, stellar neutrino energy loss, thermal storage and pressure-volume work. Specific internal energy and nuclear energy conventions must avoid counting nuclear mass changes or escaping reaction-neutrino energy twice. At fixed composition the gravothermal stellar energy generation is $-TDS/Dt$. Energy transport processes redistribute heat rather than creating it.