Abstract

Contributed Talk - Splinter StarFormation

The Role of Radiative Torques in L43

M. Scheiter, S. Wolf
Christian-Albrechts-Universität zu Kiel, Institut für Theoretische und Astrophysik

We investigate the influence of anisotropic radiation fields on the alignment of dust particles by magnetic fields, known as radiative torque alignment (RAT). In this study, we take advantage of the unique spatial configuration of the molecular cloud core L43, which contains an embedded yet optically visible star acting as an anisotropic radiation source. Based on polarization maps obtained at wavelengths of 154 μm (SOFIA/HAWC+), as well as 450 μm and 850 μm (JCMT/SCUBA-2), which show variations in the degree and angle of polarized emission across all wavelengths, we analyze the global polarization spectrum of this source. We find a negative slope of the polarization spectrum and derive plane-of-sky magnetic field strengths ranging from approximately 25 to 97 μG, varying with wavelength. Compared to three-dimensional radiative transfer simulations, this finding can at least partially be attributed to variations in dust properties and temperatures along the line of sight. However, the additional influence of changes in the magnetic field orientation along the line of sight cannot be ruled out. These results favor radiative torques as the primary mechanism of alignment, as they indicate that the degree of polarization is dependent on temperature and hence the strength of the local radiation field.