A telepathic exile: Tarquin
Tarquin's homeworld is a planet about 30 light years from Tarquin's planet. It has been described as "a wonderful place to live."
One in every fifty million inhabitants of the planet is born with telepathic abilities. This gift is considered dangerous, as telepaths are seen to be a threat to the rest of the population. They are exiled to other planets to live out their lives in isolation such as Tarquin was condemned to his lonely planet. (ENT: "Exile")
At least one of this species had left the Expanse by 2154, though he had had the misfortune to be captured by Orion Syndicate slavers in the Borderland. (ENT: "Borderland")
Tarquin's homeworld might lie within the Delphic Expanse, though this was never explicitly mentioned, and members of Tarquin's species were seen on both sides of the Thermobaric cloud surrounding the Expanse.