Oh, no, in "the Kzin planet" I think it's definitely a case of Kzin being used as a noun adjunct, which is just another way of saying that the noun is being used as an adjective. Grammar terminology is unfortunately often needlessly complicated, when it's just a simple idea. The only reason I said it was probably an anomaly is because it's like the rest of the dialog was scrubbed to reduce the number of independent terms, perhaps in some attempt (misguided or not) to avoid confusing viewers, and that one case slipped by.Personally, I take it that "the Kzin planet" is merely an alternate phrasing of "the planet Kzin." It seems to me to refer to the planet itself by name, even if it is oddly phrased in context. At the most, it possibly indicates that Kzin can also be used as an adjective like Kzinti (see below).