Grace names Tau Ceti e Adrian in Project Hail Mary.
The name appears after Grace and Rocky investigate the planet’s role in keeping Tau Ceti from suffering the same stellar crisis as the Sun. Rocky is an Eridian alien, and his mate’s name is translated into the human name Adrian. Grace chooses it as a practical English label for Tau Ceti e.
The joke is a reference to the Rocky film series. In those films, Rocky Balboa’s romantic partner is Adrian Pennino. Because Grace’s alien companion is called Rocky, naming the planet after Rocky’s mate creates one of the story’s most recognizable cultural references.
Adrian is not the planet’s formal astronomical designation. Tau Ceti e is the scientific catalog-style name, with “e” identifying it as one of the proposed planets associated with Tau Ceti. The story’s fictional planet is also important because its atmosphere contains Taumoeba, an organism that consumes astrophage and explains the star’s relative stability.