Variable star FK Comae Berenices

Variable stars FK Comae Berenices are a type of variable whose brightness fluctuation is only a few tenths of magnitude. They are giants of spectral type G and K that rotate at high speed and whose surface has a non-uniform brightness. The period of variation in these variables corresponds to their period of rotation, and may also be binary spectroscopic systems. It is possible that these stars represent a later stage in the evolution of a binary system with a common envelope, where the two nuclei have already merged.

FK Comae Berenices - Class Prototype - 31 Comae Berenices (LS Comae Berenices), 28 Monocerotis (V645 Monocerotis) and UZ Librae are examples of this type of variables.

wiki