Scattering of light in thin magnetized envelopes – II

• Published in: Monthly notices of the Royal Astronomical Society 2023-05, Vol.521 (3), p.3962-3971
• Main Authors: Silant’ev, N A, Alekseeva, G A, Ananjevskaja, Yu K
• Format: Article
• Language: English
• ISSN: 0035-8711; 1365-2966
• DOI: 10.1093/mnras/stad805

ABSTRACT We consider optically thin spherical stellar envelopes with dipole magnetic field. The source of magnetic dipole field is assumed point like and emits the non-polarized monochromatic radiation. This paper carry on the previous paper of authors, where the general theory is presented and the circular polarization of scattered radiation is calculated for small values of magnetic fields corresponding to parameter x ≪ 1 (x = ωB/ω ≃ 0.933 × 10−8λ(μm)B(G)). The Stokes parameters of scattered radiation mutually transform into each other due to interference. Here we obtained the explicit formulas describing the transformation of all Stokes parameters for any value of parameter x. The qualitative discussion of these formulas is presented. These formulas show that for x ∼ 1 the transformation leads to large variations of all Stokes parameters. The linear and circular polarizations acquire oscillating dependence on the propagation path. For x ≫ 1 the single scattered radiation has very small circular polarization of the order ∼1/x ≪ 1 and large linear polarization. In this case the transformation gives rise to additional value of observed circular polarization, which is proportional to initial single scattered value. The observed linear polarization acquires small inclination angle relative to the plane ‘line of sight–direction of magnetic dipole’ due to existence of small circular polarization. The Stokes parameters of single scattered radiation from all envelope without taking into account the interference effects are given for x ≫ 1.