Near‐Infrared Polarimetric Study of S140 IRS

Abstract

We present H- and Ks-band imaging polarimetry for the star-forming region S140 IRS and spectropolarimetry from 1.26 to 4.18 μm 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.