The millimeter observations of dust in protoplanetary disks show us spectacular structures like numerous gaps, vortices and spirals. In particular, IRS 48 disk demonstrates a large vortex-like structure. Molecular lines provide information about disks that is complementary to dust continuum observations: formaldehyde was found on the inner edge of the IRS 48 vortex, along with detections of SO2 and CS isotopes.
We use a reduced chemical network containing main carbon- and sulfur-bearing species to find the molecular species which can be sensitive to the gaps in dust, as well as to accumulation of the dust grains in the vortex. We find that SO molecule is the main reservoir for sulfur in IRS 48, for adopted disk model as in Bruderer et al. 2014. While SO is very sensitive to the gap edge, it cannot trace the vortex as it is weakly responding to the local increase in dust. Instead, SO2 molecule abundance can be expected to drop quickly within the vortex, making it an interesting tracer of dust-trapping structure.
