LO Pegasi: an investigation of multiband optical polarization

Abstract

We present BVR polarimetric study of the cool active star LO Pegasi (LO Peg) for the first time. LO Peg was found to be highly polarized among the cool active stars. Our observations yield average values of polarization in LO Peg: PB= 0.387 ± 0.004 per cent, θB= 88°± 1°; PV= 0.351 ± 0.004 per cent, θV= 91°± 1° and PR= 0.335 ± 0.003 per cent, θR= 91°± 1°. Both the degree of polarization and the position angle are found to be variable. The semi-amplitude of the polarization variability in B, V and R bands is found to be 0.18 ± 0.02, 0.13 ± 0.01 and 0.10 ± 0.02 per cent, respectively. We suggest that the levels of polarization observed in LO Peg could be the result of scattering of an anisotropic stellar radiation field by an optically thin circumstellar envelope or scattering of the stellar radiation by prominence-like structures.