Circinius IV

Circinius IV is a terrestrial world in the Circinius system and a colony in the Human Sphere. Its largest settlement was the Corbulo Academy of Military Science (CAMS).

Etymology
Circinius IV is the designation and official name of the world, though some early surveys called the planet HD 128020 IV after the formal designation of its parent star. Since the earliest explorations of extrasolar planets, it has been common to give certain star systems more memorable, or marketable, names than their original designations; in cases such as Circinius and Eridanus system, for example, unremarkably-named systems have been renamed after the constellations they are in. It has since been pointed out that the planet's name technically incorrect as the constellation the system is in is named "Circinus", Latin for "compass", while "Circinius" is seemingly meaningless. This seems to have been the result of a mistake or a typo; early documents use "Circinus" and "Circinius" interchangeably, and the latter became the standard spelling only after the 2410s. Although the name Circinius has become common in military and civilian use alike, astronomers continue to prefer the star's classical designation, HD 128020, in formal documents.

Colloquially and in CMA and CAA documents, it has been referred to as just Circinius. Later UNSC, UEG and Phoenix Initiative documents have given the planet the provisional name of Corbulo after the school.

Initial discoveries and usage
Circinius IV was originally surveyed in the 2380s. Its somewhat Earth-like characteristics made it noteworthy initially, but the lack of rare earth minerals, relatively harsh terrain, high gravity and eccentric day-night cycle made it unpopular among civilian colonists, corporations and for a time, governmental planners. A small colony was established on the planet in the colonization boom of the 2390s, though the effort was ill-fated from the start. After various setbacks and financial difficulties, including the founder of the colony being exposed as a fraudster, the colony had mostly emptied after just twenty years. Meanwhile, Circinius IV became the target of persistent campaigning by planetary conservationist groups campaigning for the planet to be declared a nature preserve due to its still mostly-pristine state.

Due to the world's lack of noteworthy resources, the initial colony's misfortune and the ongoing ecological debate, Circinius faded into the background as other colonies like Arcadia took precedence over it. While the planet hosted only small scientific outposts, the Circinius system became home to a secondary waystation to colonies further out in the Polona and Grenadi sectors, such as Biko, Mesra and Bliss. Most of the ships passing through the system did so through one of the outer ice giants, which hosted a modest stopover station and fusion fuel refinery, with Circinius IV being little more than a footnote in most catalogues of the system.

The planet began a rise to some prominence decades later, as tensions in the Outer Colonies heated up. The planet's physical position made it quite astropolitically valuable, leading to various plans on how best to utilize its position. This was a minor part of the larger schism occurring between the CMA and UNSC. The CMA wanted to set-up supply stations and resource extraction sites to help boost the local economy and make the sector more self-sufficient. The UNSC argued for more militaristic and esoteric uses for the planet to help assert further control over the sector. A compromise was reached soon after; a military school connected to a few smaller civilian settlements with a space elevator connecting to a larger civilian-run orbital facility opened in the mid-2470s.

The placement of Corbulo Academy on Circinius IV was a decision largely driven by the upwelling of the UEG's Pan-Humanist ideology as it existed in the mid-to late 25th century. Placing an elite UNSC military school on an Outer Colony was contentious for reasons both logistical and astropolitical. The project's proponents argued that whereas most UNSC and UEG institutions were located in SolCore or the Inner Colonies, having some of them distributed across human space would be a concrete act showing that the UNSC truly represented all of humanity. At the same time, a military school on a harsh frontier world was meant to teach the students, or "the future of the UNSC", an idealized pioneering spirit that was widely romanticized as the dynamo of the UEG's development, even as the actual settlers of the Outer Colonies were often tacitly looked down on.

Only a few scant discussions took place about partially increasing the civilian presence on the planet, however an expansion of military assets beyond the perimeter of the school was quickly approved and set in motion. Unofficially, a cabal of planners had started to develop a master plan to hopefully develop a new loyalist colony around the school and a network of mountainside bunkers of varying use. This cabal believed that this loyalist colony could help bring stability to the astrographical region as well as being an excellent hideaway and military installation.

The Great War
Any and all plans were rendered unusable when the school and surrounding human habitations were wiped out during the Great War. Though Covenant glassing operations only occurred on a localized level due to the small scale of the human presence, subsequent wildfires ravaged a far greater area of the surface. Beyond vigils and memorials for those who died during the battle, the planet faded again into relative obscurity.

Reconciliation era
The Phoenix Initiative and the UNSC have earmarked the planet for potential development in the future, when reclamation operations begin in the outlying worlds of the Vela-Scorpius Quadrant. However, this was still projected to take decades as of the mid-2560s. Until then, a small UNSC military listening post was set up in the system to deter the raiders, pirates and miscellaneous independent groups both human and ex-Covenant who now lurk the Outer Colonies of Quadrant 2. Post-war scouting missions to the planet revealed the remains of small independent human settlements established since the planet's fall, likely by salvagers or groups of refugees. However, these settlements were long gone, with most signs pointing to them having fallen prey to Jiralhanae and Kig-Yar raiding parties.

Topography and climate
Circinius IV is a largely landlocked world, with rivers, smaller lakes and two inland seas cutting through the landscape. The inhabited portions of the planet, centered on the equatorial highlands, are temperate, and similar in many regards to portions of old Russia and the United Republic of North America. These regions feature vast coniferous forests and mountain ranges, similar to terrestrial taiga. Volcanic eruptions frequently spark large-scale forest fires, and only small areas of the planet are deemed tectonically stable enough to house permanent settlements. Toward the poles, the boreal forests give way to tundra and ice sheets, flecked with exposed igneous rock. At the time of its colonization, the planet was experiencing a glacial maximum, with large portions of the surface covered in ice sheets. The planet also has a seasonal cycle, with winters being long and harsh due to the nearly ten-year long orbital period.

A dense world, Circinius IV has a high gravity, which was one of the factors that made it unattractive to colonists, along with active volcanism and tectonic instability, which are exacerbated by tidal effects from the planet's complex system of moons. Its mineral composition is unremarkable, mostly common earth minerals, such as nickel and gold. The Circinius system at large is likewise unusually poor in natural resources, which made it largely a stopover on the way to worlds further out.

Society and culture
Most of the activity on Circinius IV's surface revolved around Corbulo Academy, with a small military town having formed around the school. Most of the civilian population around the academy either worked in the campus or provided services for its staff and students; most of the colony's foodstuffs were farmed locally. When CAMS was active, a space elevator connected the school and its surrounding settlements to an orbital named Praetor Station. Outside the school, other settlements were largely scientific in nature, studying the planet's native ecology and climate. Large swathes of the planet have been protected as wildlife sanctuaries due to the unique (and dangerous) fauna present there.

A fringe conspiracy theory by the Reacher author and online personality Shawnee Terrel, first detailed in 2516, claims that Circinius IV is one of six "gift worlds" home to secret crypts harboring advanced technology and spiritual enlightenment left behind by the purported ancient civilization known as the "Star Walkers". According to the theory, the colony's lack of development is due to a UNSC cover-up to prevent the alien relics from being discovered by the population at large. However, no xenoarchaeological discoveries have been reported on the planet in mainstream scientific literature, and the scientific community regards Terrel's claims as entirely fictional, with skeptics having pointed out numerous discrepancies, factual inaccuracies, and leaps of logic in her statements.

Since settlements began on Circinius, the original trees of the world have been used in various forms such as furniture, construction, and other personal effects. Most of the furniture and affects have ended up in the hands of dignitaries, collectors and military personnel. Long after the destruction of the settlements that could make anything from this wood, some have claimed to have new Circinian wood products. The authenticity of some these claims are dubious.