  Neutrino and axion production in neutron stars occurs mainly as
bremsstrahlung from nucleon-nucleon (NN) scattering. The energy radiated via
neutrinos or axions is typically very small compared to other scales in the
two-nucleon system. The rate of emission of such "soft" radiation is directly
related to the on-shell NN amplitude, and thereby to the NN experimental data.
This facilitates the model-independent calculation of the neutrino and axion
radiation rates which is presented here. We find that the resultant rates are a
factor of four below earlier estimates based on a one-pion-exchange NN
amplitude.
