Complex sentence: FK Comae Berenices, which varies between 8.14m and 8.33m over a period of 2.4 days, is the prototype for the FK Com class of variable stars.
Split into simpler sentences: FK Comae Berenices is a variable star that varies in apparent magnitude between 8.14m and 8.33m over a period of 2.4 days. It is the prototype for the FK Com class of variable stars.