  We compute the detailed energy spectra of axions with two-photon coupling
produced in stellar cores over a wide range of stellar masses. We focus on main
sequence stars and base our calculations on the stellar interior profiles from
MESA, for which we provide simple fits in an appendix. The obtained stellar
axion spectra, combined with recent models of star formation history and
stellar initial mass function, enable us to estimate the properties of the
diffuse axion background sourced by all the stars in the universe. The fluxes
of this stellar axion background and its decay photons are subdominant to but
can in principle be disentangled from those expected from the Sun and the early
universe based on their different spectral and spatial profiles.
