Sirius

The brightest star in Earth's sky (save the sun itself, of course) is also home to a hub of warp bridges. In fact, Sirius is a binary star system, with a number of small planets in orbit around either star. One of these planets serves as a hub, with bridges to Parella, Redland, Bermuda, and Mintaka. With each of these bridges being one more step away from the homeworlds of Vorans, humans, and Vorans respectively, the system serves as an ideal middle ground during a number of diplomatic missions.

Sirius A

This large white star lies at the center of the system. Sirius A is about twice as large as the Sun and radiates around 25 times as much heat. Sirius A has three planets inside the orbit of Sirius B, whose gravitational influence has cleared out any other potential planets between about 6 AU and 35 AU from Sirius A. One distant planet, Fringe, orbits outside Sirius B; it is generally thought of as a planet of Sirius A, though it technically orbits around the epicenter of both stars.

Sirius B

This white dwarf is about the size of Earth, but contains the mass of the sun. Having exhausted most of its fusion-capable elements, the star long ago passed through a red giant phase, and is now relatively cool.

Its orbit around Sirius A takes places it closer or further from the larger star every 50 years - its closest point, perisir, on years ending in '44 and '94, and its furthest point, aposir, on years ending in '19 and '69. Perisir is at a distance of 8.2 AU, and aposir is at a distance of 31.5 AU.

This distance has an effect on the transit time between Sirius A and B based on the point in the orbit. At aposir, the base transit time between them is 10 years. At perisir, the base transfer time is just 1 year. (The base ΔV cost for the transfer is not affected by the different phases, only the transfer time.) Transit times from Sirius B to the outermost planet of the Sirius system, Fringe, are longer and inverted - 50 years if transiting from perisir, 5 years if transiting from aposir. The ultimate result is that nearly all of the activity in the system, including all warp bridge transfers and major settlements, happen around the Sirius B star. However, a few isolationist Bactarans have established a colony on one of the planets around Sirius A, for the explicit purpose of being far from civilization.

Saizok

Long Summer: Sirius B's eccentric orbit takes it close enough to Sirius A to scorch the planets orbiting it, and then far enough away to freeze it completely. The Long Summer, the ~5 years surrounding the closest approach, causes the second planet Saizok to rise to scalding temperatures. The freezing/heating cycle has eroded the surface of Saizok into a coarse, sandy, flat desert; millions of years of this temperature cycle has broken up any rocks and mountains that might have formed.

Saizok is home to a number of rudimentary life forms there which manage to survive for the cold parts of the long year, and burrow underground for the Long Summer, coming out in between to breed. These life forms are studied to improve cryogenic technology.

Saizok is the planet around which all four Sirius warp bridges orbit.

TMP ☼ 5 ☽ 4 ATM 2 RAD ☼ 6 ☽ 1 GRV 3

Long Spring/Fall: Before and after the Long Summer, there are two time periods of about 10 years each when temperatures are suitable for life on Saizok.

TMP 3 ATM 2 RAD ☼ 4 ☽ 1 GRV 3

Long Winter: Thanks to the realities of orbital mechanics, the long winter of Sirius B takes up about 25 years of each 50-year orbital cycle. All water in the system is frozen, and in the deepest part of the winter even nitrogen sometimes falls as a liquid from the sky.

TMP 1 ATM 2 RAD ☼ 1 ☽ 0 GRV 3

Bojal

Long Summer: Bojal, Sirius B's nearest planet, is a small planet with no atmosphere. Like Saizok, the freezing/heating cycle has an erosive effect on the landscape. However, the lack of water on Bojal reduces the effect somewhat, and the more active plate tectonics replace the large rocks and mountains on a periodic basis. Bojal ends up looking like a cracked, rocky desert.

TMP ☼ 6 ☽ 2 ATM 0 RAD ☼ 5 ☽ 1 GRV 2

Long Winter

TMP ☼ 3 ☽ 1 ATM 0 RAD ☼ 1 ☽ 0 GRV 2

Kulos

Kulos, the third planet orbiting Sirius A, lies just inside Sirius B's closest approach to the larger star; its 2.5-Earth-year orbit is in 20:1 mean motion resonance with Sirius B, and when Sirius B is at its closest point, Kulos is at the closest point in its orbit. Nonetheless, it remains locked in stable orbit around Sirius A.

The temperature on Kulos ranges from "too hot" to "much too hot". The stats given here are for aposir (Sirius B's furthest point), and the TMP rises to 8 during closest approach.

TMP ☼ 5 ☽ 4 ATM 2 RAD ☼ 5 ☽ 2 GRV 4

Fringe

This large planet orbits the Sirius AB system at a wide range with a 200-year orbital period. It was undiscovered by the Bactarans in the time they inhabited the system, but when humans enter the system during the Orion War, charting vessels discover the planet. It is cold and inhospitable, but spectroscopic analysis indicates that its moons are rich in various exotic minerals. An automated mining fleet is dispatched to Fringe by humans in 2110 (one of the last things humans do before withdrawing from the Sirius system as a part of the treaty), set to arrive at Fringe by 2118, and to return to orbit of Sirius B by 2174 with valuable minerals in tow.

TMP 1 ATM 3 RAD 1 GRV 6

Koloa

This molten ball of rock orbits close to Sirius A - so close that the star's corona lights up a fair amount of the "night" side.

TMP ☼ 10 ☽ 8 ATM 0 RAD ☼ 12 ☽ 6 GRV 5

Brinok

Another hot, lifeless rock.

TMP ☼ 8 ☽ 4 ATM 0 RAD ☼ 10 ☽ 2 GRV 3