A sub-millimeter Mapping Survey of Herbig AeBe Stars
  We have acquired sub-millimeter observations of 33 fields containing 37
Herbig Ae/Be (HAEBE) stars or potential HAEBE stars, including SCUBA maps of
all but two of these stars. Nine target stars show extended dust emission. The
other 18 are unresolved, suggesting that the dust envelopes or disks around
these stars are less than a few arcseconds in angular size. In several cases we
find that the strongest sub-millimeter emission originates from younger,
heavily embedded sources rather than from the HAEBE star, which means that
previous models must be viewed with caution. These new data, in combination
with far-infrared flux measurements available in the literature, yield SEDs
from far-infrared to millimeter wavelengths for all the observed objects.
Isothermal fits to these SEDs demonstrate excellent fits, in most cases, to the
flux densities longward of 100 {\mu}m. We find that a smaller proportion of
B-type stars than A and F-type stars are surrounded by circumstellar disks,
suggesting that disks around B stars dissipate on shorter time scales than
those around later spectral types. Our models also reveal that the mass of the
circumstellar material and the value of beta are correlated, with low masses
corresponding to low values of beta. Since low values of beta imply large grain
sizes, our results suggest that a large fraction of the mass in low-beta
sources is locked up in very large grains. Several of the isolated HAEBE stars
have disks with very flat sub-millimeter SEDs. These disks may be on the verge
of forming planetary systems.
