A SUBMILLIMETER MAPPING SURVEY OF HERBIG AeBe STARS

Journal Article · Thu Jan 20 04:00:00 EST 2011 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/727/1/26· OSTI ID:21567512

Sandell, Goeran; Hamidouche, Murad ^[1]

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1. SOFIA-USRA, NASA Ames Research Center, Mail Stop N211-3, Building N211/Rm. 249, Moffett Field, CA 94035 (United States)

We have acquired submillimeter 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 submillimeter 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 spectral energy distributions (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 timescales 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 submillimeter SEDs. These disks may be on the verge of forming planetary systems.

• OSTI ID: 21567512
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 727; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
DUSTS
EMISSION
ENERGY SPECTRA
FLUX DENSITY
MAPPING
MASS
SPECTRA
STARS