A multiple star consists of three or more stars which appear from the Earth to be close to one another. This closeness may be merely apparent, in which case the multiple star is optical, or result from the stars being physically close and gravitationally bound to each other, in which case it is physical. A physical multiple star is a form of multiple star system.

Examples

• HD 188753 is a physical multiple star with three component stars: HD 188753A, a yellow dwarf; HD 188753B, an orange dwarf; and HD 188753C, a red dwarf. B and C orbit each other every 156 days, and, as a group, orbit A every 25.7 years.
• HR 3617 is a multiple star with three component stars, HR 3617A, HR 3617B, and HR 3617C. A and B form a physical binary star, while C is optical.

See also

• Binary star
• Double star
• Triple star system
• Star system

Multiple stars

Étoile multiple