Figure 2
The column density of H2 was calculated with observations of dust continuum and molecular line emission; in addition, the column density of H2 was calculated from the best-fitting model to the line profiles of C18O (J= 2–1) assuming a constant abundance model. It indicates that significant amounts of the molecular gas are not observed because the gas has frozen out on to dust grains. Therefore, an abundance profile is included in the modelling to account for this effect.
