English: Extrasolar planet Upsilon Andromedae d lies in the habitable zone and if it has moons large enough, they may be able to support liquid water, as the image shows. On the horizon of this hypothetical earth-like moon can be seen Upsilon Andromedae d, possibly a class II planet (Sudarsky classification): since it is too warm to form ammonia clouds, the visible top ones are mostly made up of water vapor, white in colour instead of the characteristic yellow-reddish clouds of Jupiter and Saturn, and with some bluish hue due to the rayleigh scatterig.