On Protostellar Disks in Herbig Ae[solm0]Be Stars

The spectral shape of IR emission from Herbig Ae/Be stars has been invoked asevidence for accretion disks around high-mass protostars. Instead, we presenthere models based on spherical envelopes with $r^{-1.5}$ dust density profilethat successfully explain the observed spectral shapes. The spectral energydistributions (SEDs) of eight primary candidates for protostellar disks arefitted in detail for all wavelengths available, from visual to far IR. The onlyenvelope property adjusted in individual sources is the overall visual opticaldepth, and it ranges from 0.3 to 3. In each case, our models properly reproducethe data for both IR excess, visual extinction and reddening. The success ofour models shows that accretion disks cannot make a significant contribution tothe radiation observed in these pre-main sequence stars.Comment: 10 pages, 2 Postscript figures (included), uses aaspp4.sty. To appear in Astrophysical Journal Letter