Vagra II

T'Khasi – An indigenous name for Vulcan.

T'Khut – Volcanic planet that shares an orbit with Vulcan.

T'Lani Prime – Homeworld of the T'Lani species.

T'Lani III – World belonging to the T'Lani species which was wiped out in 2370 in a war against the Kellerun species.

T'lli Beta – Destination of the USS Enterprise-D before it became trapped in a cosmic string anomaly.

T-Rogoran – Home of the Dominion allied T-Rogoran species in the Gamma Quadrant.

Tagra IV – The dying homeworld of the Tagran species, whose careless industrialization began destroying the atmosphere. On stardate 46192.3, the USS Enterprise-D undertakes a clean up mission of the atmosphere which proves fruitless. However, young intern crewmember Amanda Rogers (who was unknowingly a member of the Q) uses her godlike powers to save the planet.

Tagus III – Homeworld of the secretive Taguan species who have a rich historic culture studied by the Vulcans (the only species the Taguans allow to visit their world). The Federation Archaeology Council holds an annual symposium in orbit above the planet.

Takar II – Delta Quadrant homeworld of the Takarians species that laid at one end of the Barzan Wormhole.

Takara – Homeworld of the Takaran species (not to be confused with the Takarians), the planet has an inhospitable environment to most humanoid life.

Talarian homeworld – Home of the Talarian species. The Enterprise encounters a disabled Talarian ship adrift in the Neutral Zone. (At one point in the episode, Capt. Picard describes the ship as "Taralian," but the subtitle track spells the name "Talarian.")

Talax – Homeworld of the Talaxian species. The Talaxians were known as the Talax-ilzay in their "old tongue."

Tallonian homeworld – Quark is accused of dealing with Markalian smugglers to acquire Tallonian crystals, illegal anywhere away from the Tallonian homeworld.

Talos IV – Quarantined homeworld of the Talosian species, strange humanoids who can create realistic illusions. Star Fleet General Order 7 quarantines the entire region against any and all contact under penalty of death because of the Talosians' abilities; any communication supposedly originating from the region is to be assumed false, without exceptions.

Tamar – Homeworld of the metaphoric speaking Children of Tamar species.

Tandar Prime – Planet in the 39 Tauri system. Homeworld of the Tandarian species.

Tantalus – A Federation prison colony where the warden, Dr. Tristan Adams, is discovered conducting cruel psychological experiments on the inmates. The planet is also referred to as Tantalus V.

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Wikipedia