In 2268, Ariannus was infected by a bacterial invasion that threatened to destroy all life on the planet. The crew of the USS Enterprise conducted an orbital decontamination mission to save the planet's inhabitants. (TOS: "Let That Be Your Last Battlefield")
- Ariannus was mentioned as a small note on a very large star chart graphic created for TNG:"Conspiracy." It was the image behind the chair in the room where Dexter Remmick was killed. It appears to be located within an outlined block, which may indicate that it was surrounded or was even a part of Federation territory at the time. It appears to be near Beta Niobe.