Risa, also known as Epsilon Ceti, were binary suns in the Alpha Quadrant. They were the primary stars of the Risian system and orbited by the planet Risa.
In 2256, these stars' location was labeled on the star chart "Alpha/Beta Quadrant Overview" in the ready room aboard the USS Discovery. (DIS: "Magic to Make the Sanest Man Go Mad")
In 2257, during the first Federation-Klingon War, these stars' system was occupied by the Klingons. (DIS: "The War Without, The War Within")
According to Star Trek: Star Charts (p. 62) and Stellar Cartography: The Starfleet Reference Library ("Federation Historical Highlights, 2161-2385"), Risa (Epsilon Ceti) was a multi-star with a trio of F-class stars.