Yridia is a Federation planet, the homeworld of the Yridian species. (ST reference: Star Charts) The Rings of Paltriss were removed from Yridia over several years. (DS9 episode: "Melora") In 2374, the Ariadne was travelling from Lissepia to Yridia when it was forced to detour to Deep Space 9. (DS9 novel: Hollow Men) In 2381, Yridia was attacked by the Borg during their invasion, causing much destruction on the planet. (ST - Destiny novel: Lost Souls)