double starTwo stars that lie close together on the celestial sphere. If they are physically linked by gravity so that they orbit around one another, they are said to be a physical double or a binary star. If their apparent proximity is due only to a chance alignment, they are referred to as an optical double. Sometimes "double star" is used to mean only the latter. Related category• TYPES OF STARAlso on this site: Encyclopedia of Alternative Energy & Sustainable Living Encyclopedia of History |