SIMBAD references

We present J, H, and K' images of 45 IRAS sources in the recent list by Campbell, Persson, & Matthews, which have been presumed to be luminous young stellar objects (YSOs) because of their infrared colors and their large IRAS fluxes. These objects have been classified into four groups according to two dust features in the 3 µm band–the H₂O ice absorption and the unidentified infrared band (UIB) emission. Our near-infrared images reveal that most of them (42/45) have nebulosity in at least one of the three bands. By examining the nebulosities around these YSOs, we find that (1) nebulae around the objects with the ice absorption can be explained by the scattered light of the central stars, (2) nebulae around the objects with the UIB emission cannot be explained by the scattered light alone–additional emission, most likely from very small grains, is necessary to explain the nebular colors and the surface brightness, and (3) the objects with neither the ice absorption nor the UIB emission tend to have faint or no nebulosity. We interpret the variation of nebular brightness and the color as evolutionary phases of circumstellar matter of intermediate- to high-mass YSOs.