Dust Emission and Molecular Depletion in L1498

Abstract

We present 100 and 200 mm ISOPHOT observations of the dense core L1498. We have mapped the central core by using , where is a measure of the emission from the cold dust and DI I I /V D I V 200 200 100 200 in the outer regions. The dust continuum emission provides information about the chemical depletion I /I 100 200 and the properties of cold cores where there is a lack of gas tracers. Previous observations of L1498 show that the emission from CS and CCS lies outside of the NH core. The peak in lies close to the previously DI 3 200 observed NH peak. A comparison with high spatial resolution observations of C O emission shows that the 18 3 maximum coincides with a dip in the C O emission at the core center. We estimate that the depletion factor 18 DI 200 for C O in this region is at least 8 and is likely to be much larger. Such high depletion has significant implications 18 for studies of gas-grain chemistry and protostellar cores.