Tau Ceti system (The Expanse)

Tau Ceti (τ Ceti) is a star system located 11.9 light years from the Sol system and was one of the first systems, excluding the Sol system, that was colonized by humans in Scenario: The Expanse. It is made up of a single star (Tau Ceti) and several planets and asteroids fields orbiting it. The ship that brought the first people to Tau Ceti was SS Enterprise.

Tau Ceti
Tau Ceti is a G8 class star and the only star in the Tau Ceti system. Several massive mirrors orbit the star, similar to the ones orbiting the stars in the Alpha Centauri system. These mirrors reflect the light of the star and focus it into solar panels who use it to generate a vast amount of energy which is transported across the system with lasers. Small colonies often buy some energy from the nations and companies who own these solar panels. Several nations in the Tau Ceti system decided to construct a so-called stellaser (short for stellar laser), 2 massive mirrors were constructed, specifically designed to reflect green light. This light would react with the ionized iron in the star’s corona and cause light to bounce back and forth between the two mirrors. This laser then emitted it and it was used for interstellar highways. stellasers are curren extremely common in most colonized systems.

Tyr (Tau Ceti I)
Tyr, previously known as Tau Ceti g, is the first planet in the Tau Ceti system. Tyr has a red color, but unlike Mars whose red color comes from rust (iron oxide), its color comes from Mercuric oxide. The planet contains an abnormally large amount of mercury, this combined with the planet’s fast rotation lends it the nickname Quicksilver. The planet has no permanent population and most people only come for a short visit or to conduct research. Several research centers are located on the planet, including the famous Fenrir Military Research Center, named after the giant wolf in Norse mythology that bit of the arm of Tyr. This base is by far the largest on the planet and specializes in long-distance projectiles like interplanetary and even interstellar missiles, the latter one being abandoned after the realization that they had little practical use. The other bases are mostly about mercury and using genetic engineering to change creatures to live in an environment where mercury is prevalent. Lastly there is also the Tiw-research base, which contains the largest particle accelerator ever created by humanity.

Baldr (Tau Ceti II)
Baldr, previously known as Tau Ceti h, is a big Terra-like planet, with about 2 times the mass of Terra. The planet’s atmosphere is mostly made up of water vapor (about 81%) making the surface extremely hot because of the greenhouse effect. The average temperature on the planet’s surface is nearly 300ºC. Baldr is home to several floating habitats that use helium or other gasses to float inside the atmosphere, these cities aren’t connected with eachother and the only way to travel from one to another is with a zeppelin. One of these cities (Hoder) is home to a space elevator, which is anchored on the planet’s surface, this elevator is the only affordable way to get of the planet and into space. Baldr is controlled by the Baldr Republic, a small nation that has bare any influence over the rest of the system and mostly keeps to itself. It is the only nation in the system that does not have a base on Tyr.

Freyja (Tau Ceti III)
see Freyja (The Expanse)

Freyr
Freyr is the moon if Freyja, orbitting at a distance of around 240,000 km. The moon has 4 cylinders: Njörðr (often written as Njörd), Skaði (often written as Skadi), Gerðr (often written as Gerd) and Óðr (often written as Odr or Od). These four cylinders together form the United Freyr Republic (UFR). Each cylinder has a harbor tower which regulates travel and docking, that is covered with dust. Ships land on landing platforms and either have to bring their cargo to the cylinder from the outside with a hyperloop or are lowered into building which fills with air and is connected with the cylinder itself, depending on how rich the cylinder in question is.

Odin (Tau Ceti IV)
Tau Ceti f is the biggest planet in the Tau Ceti system, with a mass of around 4.5 M⊕. It is a cold super earth, residing just outside of the habitable zone of its star. The planet has a thin atmosphere of CO2 and nitrogen. The planet is mostly covered in a layer of ice, leading some scientists to speculate that the planet was once located in the habitable zone and maybe even had life, though no evidence of that has been found. The planet is mostly controlled by the 6 largest cities on the planet: Ymir, Grid, Vidar, Aegir, Surtr and Skadi, these 6 cities have fought dozens of wars against each other, these wars are called the Odinian wars, the last one ended in 3458. The planet has a space elevator located on neutral ground. The main export of the planet is ice, but also the nitrogen in the atmosphere. The planet is often seen as the 2nd most important planet in the system, after Tau Ceti III.

Hoenir
Hoenir is the closest moon to Odin, orbiting at a distance of just over 400,000 km. The moon is extremely cold and covered mostly in dry ice (solid Carbon Dioxide). This dry ice is the planets main export, being used for refrigeration and as a part of artificial atmospheres. Water ice is another export allong with several metals found beneath the surface. The capital of the moon is Vili, a city with a population of 3 million people, about 3% of the population of Hoenir, making it the biggest city on the moon. People can get on and of the moon using launch loops. There have been some tensions between Hoenir and Odin over the autonomy of Hoenir, though these have mostly subsided with the exception of some extremists that commit terrorist attacks on Odin.

Frigg
Frigg is the furthest of the 2 moons of Odin, orbiting at a distance of 600,000 km. There are 3 O’Neill Cylinders within the asteroid. Ve is the capital of Frigg and has the largest population at about 10 million. Burr is the second biggest of the cylinders, having a population of 6 million, it is also the one with the biggest harbor. This harbor works similarly to the ones on Ceres, having ships land in a crater and using truck-like vehicles to bring materials and/or people to the asteroid. Bestla is the final cylinder, having a population of only 1 million people, it is the smallest and poorest of the cylinders and often seen as nothing more than a slum. The asteroid has a small independence movement (named Fjorgynn) but this movement has never had a large amount of members or real public support.

Tau Ceti Asteroid Belt
The Tau Ceti Asteroid Belt is about twice as big as the Sol System Asteroid Belt. The majority of asteroids are C-types, a minority are S-types and finally a very smalle amount are M-types. A large amount of asteroids have a cylinder in them. Most of these form their own state or city-state or form a federation or union with a few other asteroid bases. The largest of these unions is the Tau Ceti Asteroid Union (TCAU), which contains nearly 2000 asteroids. Living conditions in the belt vary drastically, from nearly uninhabitable stations like Mimir where the majority of the population has no job and riots are an almost daily occurrence. To luxurious paradises like Tyr, an asteroid with one of the biggest harbors in the system, thousands of ships dock everyday and bring goods and profit to the inhabitants. This is the main reason that the Tau Ceti Asteroid Belt is more divided than the Sol System Asteroid Belt.

Ymir
Ymir is a dwarf planet that is located inside the Tau Ceti Asteroid belt. Aquamarine covers a large amount of the planets surface. The reason for this is unknown and has led some people to attribute it to aliens or gods. The dwarf planet is mined for this aquamarine and other beryl minerals there is also a lot of ice at the poles. Ymir is home to 200 million people, most of which mine aquamarine and ice. The capital of the planet is Aurgelmir and has a population of 2 million people. The dwarf planet is also home to several launch loops, magnetic rails that propel spaceships so that they can escape the planet’s gravity.