Japetus Temperature Map

Caption NASA originale:"Temperatures reach nearly 130 Kelvin (-226 F) at noon on the equator on the dark material that covers most of this side of Japetus, making high noon on Japetus's dark side probably the warmest place in the Saturn System. This is much warmer than temperatures on the moon Phoebe - as measured by the composite infrared spectrometer in June 2004 - which peaked near 112 Kelvin (-258 F). That's because, although Phoebe is almost as dark as Japetus's dark material and absorbs nearly as much sunlight, Phoebe rotates much more quickly (once every 9 hours, compared to 79 days for Japetus). That means the surface has less time to heat up during the day. Temperatures on Japetus' bright material are much colder, peaking near 100 Kelvin (-280 F), both because the bright material absorbs less sunlight and because it is further from the equator on this side of Japetus".