THE S106 STAR-FORMING REGION

We present a K-band image, near-infrared photometry and I-band polarization data on the bipolar H II region S106. Assuming a distance of 600 pc we find S106 to be associated with a 0.3 pc radius protocluster of about 160 stars (> 1300 M. pc-3), embedded in the molecular cloud surrounding S106. Only a few of the stars in this cluster show reflection nebulosity surrounding them, which we interpret as a sign of very young age. We derive an age estimate of 1 x 10(6)-2 x 10(6) yr for the cluster. The K-band brightness function in this cluster rises smoothly to the completeness limit of K = 14.0 mag. Only within the last 10(5) yr has a star formed that is sufficiently massive to remove significant amounts of gas from the protocluster and end further star formation there. Polarization data on embedded and background stars near S106 confirm earlier results about the magnetic field orientation in its parent molecular cloud.