Arun
The world of the story, Arun is actually a moon of the dwarf star Veria. It is one of 13 moons orbiting Veria.
The most marked feature on Arun is a deep “V” shaped gouge on the Island continent of Gohrys, created by a driving blow from an ancient object. This gouge caused molten inner core of Arun to spew up and cauterize, at the same time, the materials reacted with the radiation from Veria, refusing to totally close. This energy pressure occurrence is what gives Arun it’s spin. A rotational day is 20 hours.
The length of orbit around Blys, the central star, is 17 years. However, the people of Arun measure time in relation to Veria, which Arun orbits every 10 months.
Arun has a modest axial tilt, reducing the effect of “seasons” in that regard, but during it’s orbit around Veria, for 22 days, Veria blocks out Blys in an eclipse. This is called the Verian season, and temperatures plunge as the days continue without the primary sunlight.
The Verian season is not as cold as it could be, and in fact, the only reason that life continues during this time, that the oceans do not freeze, etc, is that Veria radiates its own heat and light, seen as a reddish-violet glow.