Disks around Early B Stars

Although high mass star formation models predict that massive stars form with rotating accretion disks, direct observational evidence for the presence of these disks around high mass stars is rather scarce. Therefore, observational constraints on the disk structure and physical parameters (and consequently on the theoretical models) are weak and very limited. We propose to observe a small sample of bright early B-type stars which are believed to possess circumstellar accretion disks, based on previous observations, in order to directly detect the disks via their dust emission at MIR wavelengths. In these systems, the in-falling envelopes appear to have dispersed but the circumstellar accretion disks remain. The spectral energy distributions derived from the proposed FORCAST observations will be fit with models of young stars and used to determine the physical characteristics of the disks (sizes, structure, masses, and temperatures) in these sources. SOFIA with FORCAST provides the only means of studying the disks in these young, massive systems at the MIR wavelengths where their signatures are expected to be the strongest.