SIMBAD references

We report the detection of very cold dust in a small and isolated dust cloud. Observations at 60, 90, 135, and 200µm show a constant surface brightness ratio I₁₃₅/I₂₀₀ and a flattening of I₉₀/I₂₀₀ towards the cloud centre. The dust temperature derived from the far-infrared colours can be confined to the range of 12-15K assuming a λ^–2 dust emissivity. The 60µm emission comes mainly from outer dust layers surrounding the core. We infer that a fraction of the power in the 90µm band comes from the warmer grain component also causing I₆₀. This fraction is approximately equal to the total power in the 60µm band. The cloud is also detected in ¹²CO, ¹³CO, CO¹⁸, HCO⁺ and CS. The detections indicate that the dust emission is associated with a molecular cloud core where n(H₂) ≥3x10⁴cm^–3. Using the column density derived from the molecular observations we find an extinction cross section per H-atom of 4.1-9.5cm²/H-atom.