ELDIRAO
The Rao system takes its name from the red dwarf star that serves as its Sun and the major god of the pantheon worshipped in its planetary system. At times, they were used interchangeably, in accordance with beliefs of Raoism. It is likely that the whole system is also referred to as “the Rao system” and tied to Raoistic belief in accordance with the Kryptonian cosmogony. Raotist creationism called for the tale that Rao the god had created the solar system. The Kryptonians called the red dwarf for “Eldirao”, literally Kryptonese for “star of Rao”, from el meaning star, although they sometimes merely referred to it under the name of Rao. It is possible that the Rao system was a two-star (binary) system.
VALOR
In the comics, however, the planet Daxam (sometimes located in the system of Rao, and sometimes in others) is said to have its own sun, Valor, similar to Eldirao, suggesting that the Rao system is a binary star system with two stars. Valor is far smaller than Rao, which is estimated to be seven times larger than our Sun.
MOONS OF KRYPTON
Krypton is mostly described as having two moons, but evidence suggests that there were once more satellites. Additionally, no other planets in the Rao system had moons.
WEGTHOR AND MITHEN
Krypton had two moons, one of whom, Wegthor, was destroyed by a scientist, but also seemed to sustain presumably Kryptonian inhabitants:
One of them, Wegthor, was accidentally destroyed by the deviant Kryptonian scientist Jax-Ur, who was experimenting with a nuclear missile that was accidentally diverted from its intended destination (an approaching meteor). The disaster killed 500 inhabitants of the moon (...) The other [moon], Mithen, had an unknown fate after Krypton's immolation.
ADDITIONAL MOONS
However, comics also mention there as having been two moons at the time immediately before its destruction, suggesting if not verifying that Krypton once had three moons. At the time of Krypton’s destruction, its moons were Mithen and Koron. A fourth moon, Xenon, had flown out of orbit and come to be considered a planet on its own right and, had, like Argo in some versions, (mistakenly) been called its sister world.
(....) under the soft radiance of Krypton's two moons; but it is firmly established in the chronicles that the Kryptonian scientist Jax-Ur destroyed one of Krypton's moons prior to this period, (...) clear evidence that Krypton had three moons - one of which was evidently named Koron - in the not-too-distant past. In addition, Xenon, the so-called twin world of Krypton, was evidently Krypton's fourth moon, sometime in the ancient past, until it spun out of its orbit and left Krypton forever.
Sources:
https://en.wikipedia.org/wiki/Rao_(comics) https://en.wikipedia.org/wiki/Krypton_(comics) http://theages.superman.nu/Encyclopaedia/krypton.php#planet Diagrama Planetario del Sistema Rao