The twin suns are named "Alured" (yellow, brighter) and "Alerot" (blue, lighter, which follows Alured by about two hours). Arkus experiences a 24 hour day, with Alured providing normal Earth-like daylight, followed by about two hours that only Alerot is in the sky. This period is known as "the blue gloaming," with the world bathed in blue-tinted light.