Map from Star Trek Star Charts by Geoffrey Mandel; Pandora, Sitol and the station are added later of course ;-)
The Pandora System
The Pandora system is one of a few planetary systems on the edge of the Din'ghes Nebula in the Din'ghes sector.
It consists of 4 planets orbiting a class A star. Between the first and second planet is a small asteroid field.
Pandora I
Orbit: 94,100,000 km Diameter: 5,200 km
Pandora I is a small C class planet with a dense carbon dioxide atmosphere. Due to the "greenhouse effect" caused by this atmosphere and the distance to the system's star, the surface temperature is about 1000° C.
Pandora II
Orbit: 151,200,000 km Diameter: 16,340 km
Pandora II is a class O planet, slightly bigger than Earth. About 97.2% of the planet's surface is covered with water.
The average surface temperature is 35° C.
In orbit of this planet is Pandora Station (SB-243).
About 90 kilometers below the water surface, at the edge of an even deeper trench, is a small scientific Outpost Poseidon (also called Poseidon Station), which is manned by a small team of civilian scientists, mainly marine biologists, although recent discoveries also caused a team of archaeologists to be present.
Pandora III
Orbit: 1,219,300,000 km Diameter: 132,900 km
Pandora III is a class J planet, a gas giant. The planet has a small ring and 3 moons (1 class G, 2 class I)
Pandora IV
Orbit: 3,210,000,000 km Diameter: 4,562 km
Pandora IV is a class G planet.
Location (old/wrong)
Old information:
Pandora Station to
Earth (Sol system): 68 ly (lightyears)
New Amsterdam Colony (Zon system): 99 ly
Betazed: 55 ly
Briar Patch/Ba'ku: 30 ly
Trill: 40 ly
Bajor: 63 ly
Starbase 375: 38 ly
Romulus: 155 ly (closest border Romulan Star Empire: 140 ly)