  Young stars with masses 2-8 Suns, called the Herbig Ae and Be stars, often
show a near-infrared excess too large to explain with a
hydrostatically-supported circumstellar disk of gas and dust. At the same time
the accretion flow carrying the circumstellar gas to the star is thought to be
driven by magneto-rotational turbulence, which according to numerical MHD
modeling yields an extended low-density atmosphere supported by the magnetic
fields. We demonstrate that the base of the atmosphere can be optically-thick
to the starlight and that the parts lying near 1 AU are tall enough to double
the fraction of the stellar luminosity reprocessed into the near-infrared. We
generate synthetic spectral energy distributions (SEDs) using Monte Carlo
radiative transfer calculations with opacities for sub-micron silicate and
carbonaceous grains. The synthetic SEDs closely follow the median Herbig SED
constructed recently by Mulders and Dominik, and in particular match the large
near-infrared flux, provided the grains have a mass fraction close to
interstellar near the disk's inner rim.
