The Kerenza solar system is the setting of the Illuminae Files series. It is a solar system with a singular star and seven planets in orbit. It has one gas giant and six rocky/exoplanets.
Kerenza is the sun and the center of the system. It appears to be a small star, which accounts for the icy temperatures on Kerenza IV.
Kerenza IV is the fourth planet from the sun. It is plunged in icy temperatures and snow. It is the only populated planet in the Kerenza system (as far as we know), and is home to an illegial hermium mine owned by WUC.