Linear polarization of binaries II. Phase function : wQ~(µ)Q~' (µ')

Abstract

This paper presents a method of calculating linear polarizations in close binaries whose surfaces are distorted due to tidal and rotational forces. Limb-darkening effect has been taken into account. Particles of different sizes are embedded in the outer atmosphere. The law of differential rotation of the primary is considered in analytic form: ??=3D b1 + b2 w2 + b3 w4, where b1, b2 and b3 are constants and w is the distance of a point P (r,?,?) from the axis of rotation of the primary. The atmosphere is assumed to be non-grey, plane-parallel and the phase function is wQ~(?)Q~? (??). Calculations are done with respect to rest frame fixed at the centre of the primary star for several functions as : mass-ratio (q) between the secondary and the primary, polar radius (rp) of the primary, wave-length (?) of the incident light, radius of a particle (1) and angle of inclination (?) with respect to the line of sight. It is noticed that polarization increases with an increase of the radius rp steadily; polarization increases with an increase of the radius of the particle (1), polarization increases with an increase of the mass-ratio q. The method of solution has been applied to several late type binaries to calculate disk integrated linear polarization of light emitted by them. When the mass-ratio q = 0, the general problem reduces to the calculation for a rotationally distorted single (primary) star.