The home world of the Tellarites.
Tellar Prime is the homeworld of the Tellarites, a stocky, argumentative people with snout-like noses. In Tellarite culture, argument is a way of showing respect and testing ideas, and outsiders who stay politely quiet can be seen as weak.
The planet was one of the four founding members of the United Federation of Planets in 2161, together with Earth, Vulcan and Andoria. In Enterprise, Tellarite and Andorian diplomats travelled with Archer to a peace conference on the planetoid Babel, and Romulan efforts to start a war between the two sides were defeated when Earth, Vulcan, Andoria and Tellar worked together.
The Tellarite ambassador Gav appears in the original series episode Journey to Babel, debating Sarek about the admission of Coridan to the Federation before he is murdered by a disguised Orion agent. Tellarites have continued to appear in later series as Starfleet officers and diplomats.