Spectral Variations and Simple Models of FS CMa

Investigation of FS CMa type objects is difficult due to a lack of systematic observations. We present a study of the group prototype, FS CMa, based on a long-term observational campaign. Our unique set of spectra obtained in 2005-2013 allows to study line formation in various parts of the circumstellar environments. We observed both short- and long-term changes in several spectral line parameters. We estimated the ionic density from the observations of the Balmer jump region and used it in modeling the spectral energy distribution (SED) and Hα profile.