Linearly polarized spectrum of Betelgeuse (with the continuum polarization level set to zero) around the Fe i (558.7 nm), Ni i (558.8 nm) & Ca i (558.9 nm) in Set 1 (left) and Set 2 (right). The upper spectrum shows Stokes I (intensity) and the lower spectra show Stokes Q (blue) and Stokes U (red). The vertical lines correspond to the positions of the Fe i, Ni i and Ca i lines in the stellar rest frame.