A Betan was the designation given to any Pelian who lived on the Beta moon of Peliar Zel. Throughout their history, Betans had been in discord with the Alphans moon and lived in a state of perpetual tension with their neighbors.
In 2337, the aunt of Betan Lathal Bine agreed to change places with her Alphan counterpart, Kalin Trose, for a week to understand each other's situation with more informed eyes.
Thirty years later, Bine found himself in a similar situation when the Alpha moon developed a way to tap into the energy from Peliar Zel's magnetic field, causing environmental damage to the Beta moon when its orbit passed through the energy beam. That strained relations again and both moons began to arm for war. Like his aunt, Bine agreed to mediation by Federation Ambassador Odan, who reminded Bine of the "iron-willed lady of Beta moon" and her willingness to do what was best for her people. (TNG: "The Host")