On the dust and gas associated with Sharpless 252

The stellar cluster and the massive molecular cloud associated with theHii region Sharpless 252 have been studied by means of multicolour polarization and molecular line measurements. The average wavelength of the maximum polarization _max and polarization efficiency for the cluster stars are similar to the values observed for the nearby field stars. Two local maxima lying only 2 apart were found in the molecular cloud core in CO, NH₃, and HCO⁺. The excitation conditions and radial velocities associated with the maxima are different.Paper presented at a Workshop on The Role of Dust in Dense Regions of Interstellar Matter, held at Georgenthal, G.D.R., in March 1986.