Heaven, the earthly world, and the Underworld
Jupiter is the brother of Neptune and Pluto; the brothers preside over the realms of Heaven, the earthly world, and the Underworld. Pluto is associated with Tuesday, alongside Mars since Pluto is the higher octave of that planet in astrology. Like with Venus, the planet Neptune is also associated with Friday because Neptune is the higher octave of Venus. Jupiter is associated with Thursday. Uranus is also associated with Wednesday, alongside Mercury (since Uranus is in the higher octave of Mercury).
Nergal
Nergal (Mars) seems to be in part a solar deity, sometimes identified with Shamash, but only representative of a certain phase of the sun (Apollo). Portrayed in hymns and myths as a god of war and pestilence, Nergal seems to represent the sun of noontime and of the summer solstice that brings destruction, high summer being the dead season in the Mesopotamian annual cycle. He has also been called “the king of sunset”. Over time Nergal developed from a war god to a god of the underworld (Pluto). In the mythology, this occurred when Enlil and Ninlil gave him the underworld.