  We present a new grid of LTE model atmospheres for weakly magnetic
(B<=10e10G) neutron stars, using opacity and equation of state data from the
OPAL project and employing a fully frequency- and angle-dependent radiation
transfer. We discuss the differences from earlier models, including a
comparison with a detailed NLTE calculation. We suggest heating of the outer
layers of the neutron star atmosphere as an explanation for the featureless
X-ray spectra of RX J1856.5-3754 and RX J0720.4-3125 recently observed with
Chandra and XMM.
