  Acoustic holes are the hydrodynamic analogue of standard black holes.
Featuring an acoustic horizon, these systems spontaneously emit phonons at the
Hawking temperature. We derive the Hawking temperature of the acoustic horizon
by fully exploiting the analogy between black and acoustic holes within a
covariant kinetic theory approach. After deriving the phonon distribution
function from the covariant kinetic equations, we reproduce the expression of
the Hawking temperature by equating the entropy and energy losses of the
acoustic hole and the entropy and energy gains of the spontaneously emitted
phonons. Differently from previous calculations we do not need a microscopical
treatment of normal modes propagation. Our approach opens a different
perspective on the meaning of Hawking temperature and its connection with
entropy which may allow an easier study of non stationary horizons beyond
thermodynamic equilibrium.
