FK Comae Berenices star
A giant of spectral type G–K which is also a rapidly rotating extrinsic variable with non-uniform surface brightness. The variations are caused by a region of cool spots (starspots) localized on one hemisphere of the star; abbr. FKCOM. The rotation and variation periods are identical and are typically several days, with amplitudes up to several tenths of a magnitude. It is possible that these stars represent a later stage in the evolution of a common envelope binary in which the cores have coalesced.