KnowraO-type starLinked fromLinked fromThe 8 pages that link to O-type star, each with the reason it gives.All 8Broader topic 3Related 2Narrower topic 1Compared with 2Harvard spectral classificationBroader topic: O stars occupy the hottest end of the Harvard sequence.Spectral typeBroader topic: O stars anchor the hottest end of the main spectral sequence.Spectral classificationBroader topic: It is the hottest main category in the standard OBAFGKM sequence.