Time-dependent spectropolarimetry of the red variable V CVn

Systematic spectropolarimetric observations over the cycle of the semiregular red variable V CVn were obtained. The observed variations across the 4955 A TiO band give further credence to the hypothesis of a photospheric origin for most of the optical polarization in this object and, in particular, they support the existence of an intermediate scattering layer in the stellar photosphere. We point out the importance of spectropolarimetry to test and improve such late-type model atmospheres, especially those incorporating spherical, non-LTE conditions