A red herring was a metaphor-derived literary device that intentionally misled the audience to form a false conclusion detracting from the relevant plot of a story.
While the crew of Enterprise NX-01 tried to determine the location of the yet unknown Azati Prime in 2153 from Degra, who eventually revealed that his family was on a colony near a red giant, Trip Tucker mused that "this red giant might be a red herring. He only told you his family was living near one of these stars. We don't know that the weapon is there." (ENT: "Stratagem")