  We use models of magnetized hydrogen atmospheres to fit the soft X-ray
thermal spectrum of the Vela pulsar obtained by ROSAT. The distance and
hydrogen column density required by our fits are in good agreement with other
independents estimates and can be considered as an argument for the presence of
hydrogen at the surface of this pulsar.
  The low temperature obtained, T = 7.85 +/- 0.25 10^5 K, is below the
predictions of the `standard' model of neutron star cooling and strengthens
previous claims for the necessity of the occurrence of fast neutrino cooling in
this neutron star.
