The (fictional) Nyx system shown in these shots consists of two stars which orbit each other at an average distance of about 40au. Nyx A is a 1.4 solar mass star that has evolved to the red giant stage. Nyx B is a main sequence G class star very much like our Sun. The terrestrial planets Clotho and Lachesis orbit Nyx B at 0.7au and 1.2au. From Lachesis, the red giant Nyx A appears as bright as Nyx B even though it's 40 times further away.
Clotho is illuminated by both Nyx B (visible in picture) and Nyx A, leaving just a slice of the planet in darkness:
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Lachesis, lit by two suns. I used Runar's Blue Venus textures for this planet.
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A double sunset on Lachesis. Note that Nyx A appears larger than Nyx B. Even though Lachesis is 40au from Nyx A, the red giant has an apparent diameter over three times that of the Sun in our sky.
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--Chris