Binary system

A binary system (or binary star) was a star system consisting of two stars.

Sirius was, as the Eleventh Doctor pointed out to Henry Avery, a binary system. (TV: The Curse of the Black Spot)

The Althosian system (PROSE: The Pit) and the Meson system (PROSE: Time of Your Life) were binary star systems. Major and Minor were the stars in the binary system which contained the planet Trion. (PROSE: Turlough and the Earthlink Dilemma)

Lucie Miller hoped that her first visit to another planet would be to one that had two suns. (AUDIO: Blood of the Daleks)

Planets with two suns included Anubis, (TV: Curse of Anubis) Aridius, (TV: The Chase) Caresh, (PROSE: The Suns of Caresh) Coralee, (PROSE: Storm Harvest) Corbo, (PROSE: The Devil-Birds of Corbo) Dido, (PROSE: The Rescue) Gliese 581d, (TV: Smile) a devastated planet, (PROSE: Lords of the Galaxy) the planet of the Gonds, (TV: The Krotons) Kandalinga, (PROSE: The Fishmen of Kandalinga) Lobos, (PROSE: The Good Doctor) the Sense Sphere, (PROSE: The Monsters from Earth) and Skaro. (PROSE: The Stranger)

Gallifrey had a "second sun". (TV: Gridlock, Spyfall) The Monk believed that the Homeworld had not originally been part of a binary system, but had been retroactively engineered into one by He-of-Many-Epithets as a precaution during the war against the vampires: the interaction of the orbital patterns of the two suns created a shifting "interference pattern" in the daylight which meant that even vampires resistant to ordinary sunlight could not walk on the Homeworld without burning. Because of these "mad orbital mechanics", the planet had "an unconventional day-night terminator": as the Monk put it, "the region in darkness [shrank] like an iris and close[d] like a fist". (PROSE: The Bloodletters)

The film Star Wars featured a scene in which twin suns set over the Tatooine desert. (PROSE: Mission: Impractical)