Near-infrared polarimetric study of S140 IRS

We present H- and K(s)-band imaging polarimetry for the star-forming region S140 IRS and spectropolarimetry from 1.26 to 4.18 mu m for the infrared source IRS 1. The polarimetric images reveal two reflection nebulae illuminated by the deeply embedded infrared sources IRS 1 and IRS 3. The nebula associated with IRS 1 does not simply show a symmetric structure, as expected in the well-known pole-on outflow model, but displays three reflection lobes. Two bipolar reflection lobes are apparently extended in the northeast-southwest direction and lie nearly in the plane of the sky. Another pole-on lobe, corresponding to the blueshifted pole-on molecular outflow, is Projected to the southeast of IRS 1. The polarimetric images also resolve an asymmetric density distribution around IRS 1; to the west there is a dense disk structure elongated in the east-west direction; whereas to the east there is a cavity. On the basis of these features, as well as previous radio continuum and CO molecular line observations, we propose that S140 IRS 1 may drive a quadrupolar outflow.