Tags: Star.
12 Ophiuchi is a variable star in the constellation Ophiuchus. No companions have yet been detected in orbit around this star and it remains uncertain whether or not it possesses a dust ring.This star is categorized as a BY Draconis variable with variable star designation V2133. The variability is attributed to large-scale magnetic activity on the chromosphere (in the form of starspots) combined with a rotational period that moved the active regions into (and out of) the line of sight.