Planetary type: Rocky world, likely interstellar capture.
Region: Traverse.
Natural satellites: three asteroid moons.
Age: 1.5 billion years (estimated).
Parent star: T-class brown dwarf.
Surface gravity: 0.6 gees.
Atmosphere: 0.5 atmospheres, close to human-breathable.
Average temperature: 12°C
Climate range: Cold arid to hot arid.
Ecosystem classification: Carbon-based, scattered evolution.
Solar revolution length: 15 days.
Day length: Tidally-locked (with terminator precession).
Settlement Type: Isolated cities.
Settlement age: 42 years.
Population: 500,000.
Allegiance: Eloran Ekumen.
Distance to Earth: 578 lightyears

Starports: Styx Port, Urcaguary Station.

Modern interstellar travel notwithstanding, brown dwarfs remain hard to spot and are only systematically explored in dense areas of space. This is the main reason why unlikely or otherwise anomalous habitable worlds seem to be concentrated in the Traverse: the well-travelled region has been thoroughly explored in the past seventy years. In any other place, save for the surroundings of the Sun, Stygia would have been missed -- and the age-old debate concerning the habitability of brown dwarfs would have remained without a conclusive answer. For despite all odds, Stygia harbors carbon-based life: tidally-locked, it is close enough to the brown dwarf to receive enough energy to maintain a biosphere made of dark, scarce plants, fungus, lichen and a thriving pseudoinsect environment. Its cool atmosphere is breathable with a simple oxygen mask and the precession of the brown dwarf at the terminator even allow for a semblance of a day-night cycle at the cool temperatures where human settlements are located. The night side is frozen, with basic life concentrated around sites of geothermal activity, while the day side is occupied by noxious, life-rich swamps and warm but liveable deserts.

In theory, Stygia should not exist. Its T-class brown dwarf is a feeble parent star, whose system is extremely oxygen-poor; its other two rocky planets are classified as "carbon worlds", whose surface is exclusively made of graphite, liquid hydrocarbons and carbon monoxide. Local asteroids are remarkably dry and metal-poor. Stygia itself concentrates 95% of the system's water and the three quarters of its heavy metals. Under the current understanding of planetology, there is no possible way Stygia could have formed in its current system through natural means. In the first years of study, the dominant theory was that Stygia was, to some extent, an artificial creation, not unlike some of the megastructures found in the antispinwards part of the Traverse. It took scientists a good decade to uncover the real origin of Stygia -- and the key was to be found in the fossils contained deep within the cold crust of the planet. Pristinely preserved, they told the tale of an impossible ecosystem; a thriving, complex environment that bore all the hallmarks of a warm planet orbiting a main sequence star, most likely an F or G-class yellow dwarf.

Stygia is an outcast. A former garden world ejected from its parent system by a cosmic cataclysm, having travelled millions of years as a rogue world, its soil and atmosphere frozen barely above absolutely zero, then captured by a brown dwarf and slowly brought back to life by its infrared radiation and tidal heating. A chance in a trillion; a world of death and rebirth, whose current ecosystem evolved over the course of the past half a billion year from pockets of micro-organisms huddled around underground geothermal hotspots during the great journey.

Founded by Eloran settlers, the commune of Stygia is mostly dedicated to studying the peculiar planet; it houses and administers the Styx Research Center, dedicated to uncovering the secret of Stygia's origin and painting an accurate picture of the world it once was -- though the original system has yet to be pinpointed, three candidate G-class stars have been identified in the Traverse and are currently under investigation. The planet is also home to several world-class exobiology laboratories, an unofficial Algorab dig site and a few cooperative farms fruits and vegetables famous for their pitch-black colour.

Illustration by Marc Garlick -- Science Photo Library/Getty Images.