Near-infrared polarization study of L1641S

Abstract

H-band polarimetric images and Ks-band images of star formation region L1641S are presented. Two reflection nebulae, Re50N and Re50, are in the north and south of the region, respectively. The polarization maps of two nebulae exhibit high degrees of polarization and centrosymmetric patterns, indicating the single scattering and small dust grains in the nebulae. There are two infrared sources, IRS1 and IRS2 in the nebula Re50N. IRS1 is the illuminating source of the nebulae and the driving source of CO outflow; IRS2 is suggested to provide considerable light at optical wavelengths. The high polarization in Re50N can be interpreted as surface scattering from the outflow at an inclination of 30 degrees. Based on the polarization arc structure, we further identified the bipolar structure of the nebula Re50N. The FU Orionis phenomenon in L1641S is discussed at the end of this paper.