Tags: Star.
HD 123657 or BY Boötis is a variable star (4.98–5.33V). This makes it a dim naked eye star. It has slow irregular variables of late spectral types (K M C S); as a rule they are giants (CO Cyg). This type is also ascribed in the GCVS to slow red irregular variables in the case of unknown spectral types and luminosities. The star is located near the end of the handle of the Big Dipper.