Sedna is a dwarf planet in the Sol system which lies in the ort cloud. It is smaller than Earth's moon.
While most objects in the Sol system are colonized to some extent, Sedna has remained virtually untouched. It was a low priority for exploration, due to the invention of slipspace drives and the prospect of exploring extrasolar planets, and it was so low on humanity's list that a manned mission was not put on it's surface until 3378.
Quite unexpectedly, the wreckage of a massive starship was found crashed on Sedna's surface. It was heavily damaged, due to thousands of years of meteor impacts, and it was discovered that the spaceship predated even the earliest known Noki ruins.
Sedna is generally avoided by most spacecraft(because of superstition), as most worlds with unexplained alien ruins are.
The only human population of Sedna is in a small community of archeologists who live around the wrecked spacecraft(With a population of 250), studying it. The community has experienced a number of strange events, such as all power going out suddenly, and mysterious cryptic messages appearing on computer screens. It is unknown what causes these strange happenings; it has even been suggested that part of the long dead crew of the ancient spacecraft's conciousness is still intact. Nevertheless, these events lead to even more superstition among visitors.