[Previous] | [Session 71] | [Next]
G. Sandell (USRA), D.A. Weintraub (Vanderbilt)
Do Herbig Ae/Be stars have accretion disks like T Tauri stars? We report the detection of 850 micron continuum emission toward 21 of 33 HAEBE stars in a JCMT mapping and archival survey; more than half the sample was observed at 450 micron as well. Of the detected sources, eight show extended, disk-like dust emission centered on the star. The others are unresolved in our beam, suggesting that the dust envelopes or disks around these stars are less than a few arcsec, similar to the sizes of envelopes and disks seen toward most T Tauri stars. Several of the detected but unresolved stars (e.g., MWC 297, Elias 1, HD 142666) have very flat SEDs in the submillimeter, suggesting the presence of dust with unusual properties or disks with large dust grains or planetesimals. These disks may be on the verge of forming planetary systems.
Many HAEBE stars lie in regions of extended dust emission; quite often, however, our maps show that the strongest submillimeter emission originates from younger, optically invisible, heavily embedded sources rather than from the HAEBE stars. Mapping therefore is essential in order to determine whether the submillimeter or far-infrared emission detected in large beam measurements is from a HAEBE star, nearby protostars or merely from the dust cloud in which the star is embedded. In addition to already known cases like R CrA, LkHa 198, and BD+40 4124, where the submillimeter emission is dominated by emission from heavily embedded Class I or Class 0 sources, we find several other regions where the same is true or where the dust emission comes the surrounding PDR/molecular cloud interface, but not from the star itself. Only one star, the extremely distant MWC 300, showed no emission at all in the SCUBA field of view.
Guest User, Canadian Astronomy Data Center, which is operated by the Dominion Astrophysical Observatory for the National Research Council of Canada's Herzberg Institute of Astrophysics.
The author(s) of this abstract have provided an email address for comments about the abstract: gsandell@mail.arc.nasa.gov
[Previous] | [Session 71] | [Next]
Bulletin of the American Astronomical Society, 34
© 2002. The American Astronomical Soceity.