Avalon

Avalon, officially named Heze III, is a terrestrial planet located in the Heze binary system, located about 74 light years (23 parsecs) away from Sol. Classified as an anomalous body by the SDC, the planet is a myriad of dualities -- a habitable atmosphere and abundant wildlife clash dramatically with its toxic soil and poisonous oceans.

The planet of Avalon is covered in a fog that partially blocks light from its parent stars, its lukewarm temperature instead coming from its highly volcanically active crust.

Heze was discovered in 2047 via the transit method of it intersecting its parent star. However, its thick fog had masked its unique properties and was not considered a habitable planet until advanced technologies had allowed scientists to discover its atmospheric composition remotely, prompting it as a prime habitable candidate and marking it for later exploration by the Final Frontier Project.

LZ Alpha (New Medan Caldera)
The SDCN Emissary 's initial landing site of the planet was on a plateau nestled inside a dormant volcano, with temperatures and conditions ideal for life to thrive. These oases, of which many are scattered across the planet, are the only places in which the native wildlife on Avalon can thrive. Surrounded by a geothermal spring with high walls, the caldera forms both a natural oasis and a sanctuary for animals (and, in the future, maybe even colonists), shielded from the toxic climate outside the caldera.

The area has been officially named LZ Alpha, but has been also given a name by the scientific community - the New Medan caldera.

Planetary Information
Avalon is the third planet from its parent star, Heze, in a six-planet star system with Heze (Zeta Virginis A) being an A-type main sequence star with about twice the mass of the Sun.

Avalon is a terrestrial planet slightly over half the volume of Earth, but with twice the density, giving a gravitational pull of approximately 0.86 G, meaning minimal adjustment is required for anyone stepping foot on the planet.

Avalon's orbital eccentricity is approximately 0.7. Its orbital inclination is 22.38 degrees and its axial tilt is almost 46.5 degrees relative to its orbital path.

Avalon has no moons - due to this, tides are not present and the planet's axial tilt is subject to severe fluctuations every few thousand years, with the planet likely entering the more extreme of these tilt phases.

Anomalous Properties
Classified as an anomalous body by the SDC, Avalon holds a plethora of mysteries that violate the conventional laws of scientists previously known, prompting it to be a high-priority research target for both the United Nations and AXIOM Corporation, both of which have poured billions of credits into funding research expeditions via the SDC's Final Frontier Project.

Apparent Age
Radiometric dating of bedrock samples as far as 2.3 miles below the surface of the planet have led to the discovery that Avalon as a planet is 3.4 billion years old, nearly 3 billion years older than its parent star, Heze. This has led to the theory that Avalon is, in fact, a captured, formerly rogue planet from a distant star system, owing to its highly eccentric orbit and unusual rotationary period. Avalon's original star system, as well as how it had sustained life even while rogue, still remains a mystery.

Eccentricity
Owing to the rogue planet theory, Avalon's orbit is extremely eccentric, so much so that it alternates between the third and fourth planet in the solar system depending on its season, occasionally surpassing the barren planet Heze IV. The stability of the planet's orbits, seemingly yet unaffected by Avalon's gravitational influence, suggests that if the rogue planet theory is correct, the capture would only have been done recently, approximately in the past 10,000 years or so. If Avalon was captured before this time period the orbits of Heze I, II and IV would have deteriorated due to Avalon's gravity.

Density
Avalon, despite only having just above half of Earth's mass, has twice its density. While the planetary core composition has not been properly analysed yet, scientists suggest the core and mantle are made up of far denser material than iron. One theory suggests the presence of hypothetical solid mercury at its core, crushed by the planet's gravity so much that it has become solid in spite of mercury's natural liquid state. Such a composition would be highly unnatural, as mercury is not found normally in such high quantities to become the main component of a planet's core.

Atmosphere
Avalon's lower atmosphere composition has a nitrogen-oxygen blend almost perfectly mirroring that of Earth, while its upper atmosphere is a cloud of particulates, ozone, methane, and other greenhouse gases, forming a nigh-impenetrable, high-albedo fog that shields the planet from Heze's heat. This gives the planet a cloudy, almost bluish-white appearance when viewed from the outside, while inside the atmosphere the sky is a gloomy dark grey or black.

Analysis of the upper atmosphere's particulates reveal clouds of ash in addition to ozone, suggesting a massive volcanic eruption (or chain of reactions) that had dispersed this cloud and caused it to block out the sun. However, temperatures on the planet had remained historically consistent according to geological surveys - signifying that either the ash was either always there, or that planetwide eruptions happen on a regular scale as part of the planet's way of maintaining a homeostatic atmosphere. The lack of this upper fog would result in the planet being cooked by its star, due to its relative proximity to the star in addition to its already lukewarm lower atmosphere caused by its plentiful geothermal springs.

Caves
Beneath Avalon's surface is a vast network of entangled, labyrinthic caves. Initial research suggests the volcano that once dominated the New Medan caldera had many lava conduits formed underneath its surface once the volcano had gone extinct, as evidenced by the heavy presence of igneous rock. However, the sporadical nature of the tubes as well as the lack of clear flow direction dispute this theory, and further studies hint that the tunnels may have been, in fact, artificially constructed.

Flora
Avalon holds a plentitude of fauna and flora, often displaying high resemblances to those on Earth, albeit with several notable differences.

Glowfruit Tree (candentis xenoarborum)
Scattered throughout Avalon lies a dominant species of evergreen tree, dubbed the Glowfruit Tree with the scientific name candentis xenoarborum, which appears to be a tree with a wood-like trunk and bioluminescent 'fruit' pods that can be seen suspended from the trees on thin vines. The roots of the tree dig extremely deep, presumably to directly tap from the underground aquifers.

The fruit of Glowfruits are cantaloupe-sized circular drupes, containing high amounts of luciferin and luciferase, compounds that produce bioluminescence, as well as sucrose and various other organic compounds, including citric acid. The fruit is marginally edible but possesses an incredibly sour taste due to the high amount of citric acid in the fruit, leading to them being used instead as organic 'lanterns' should artificial light not be available. The high amounts of acid additionally lead to the fruits functioning as low-capacity electrochemical batteries (similar to lemons) and store about 200 milliamp hours of charge per fruit at 0.7 volts.

Glowfruits normally emit white light at around 3300K, a slight warm white, but cooling the fruit has shown to change its color temperature dramatically all the way to a pale blue at 8800K, when cooled to -10 degrees Celsius or below. Glowfruit freezes and dries up below -50 degrees Celsius, at which point its bioluminescent properties are permanently destroyed.

The trees themselves possess a trunk of a light violet wood, comparable in appearance and texture to cherry. Topping it is a canopy of burgundy-colored leaves with high amounts of anthocyanin, giving the trees' appearance a highly exotic look compared to that of Earth trees.

Glowfruit in enclosed growing environments sport remarkable gestation periods of only 8-10 days and reach the height of a 1-foot sapling within approximately 1-2 months. Owing partially to this, the trees have short lifespans, living for only about 20-40 years.

Glowfruit wood inherits anthocyanin from its leaves, dyeing it a light lavender colour. While the wood itself is soft and porous - making it unsuitable as a construction material - its artisan value is often praised, and samples of the wood have been sent back to Earth for exotic woodworking.

Coexisting with the Glowfruit Trees are violet-purple colored grass and weeds, displaying heavy similarity to grasses found on Earth. The grass displays similar deep-digging roots to that of the Glowfruit tree, making weed and grass removal much more difficult than expected.

Fauna
Analysis of the soil has found microbes, amoebas, and bacteria highly resembling those found on Earth. Fungi are notably absent from the soil composition.

Multiple avian animals have been discovered on Avalon. These alien birds appear to have feathers, white-colored beaks, two eyes, and pointed crests. A majority of the birds appear to be purple or magenta in color, presumably to provide camouflage.

Underground studies conducted by probes across the planet have found small yet prominent deposits of coal and oil, highly indicating that the planet was, and still is, home to large amounts of multicellular carbon-based animals.

Upon inspection of the larger lakes and seas, there are traces of alien fish and coral present in the waters; however, they are much more sparse than what would be considered normal on Earth.

Atmosphere
The atmosphere of Avalon is composed of 59% nitrogen, 21% oxygen, 11% carbon dioxide, and 2% other gases. The atmosphere is breathable to humans without much need for protection or assistance. Part of the 2% of other gases is carbon monoxide, likely formed from volcanic eruptions and forest fires, while another significant portion is methane, thought to be similarly emitted by forest fires but also the prevalent wetlands on the planet.

Weather
Most of Avalon's weather activity consists of mildly acidic precipitation with an average pH level of 3.8, weaker than vinegar. While it is not harmful to skin, it is an eye irritant and protection should be worn during rainy days.

The thick fog over the planet can also produce erratic, violent lightning storms that can either be dry or accompanied by rain. This can lead to forest fires, some of which have been sighted burning across the planet.

During the winter season the rain freezes into snow or hail, which is also acidic.

Seasons
With an axial tilt of almost 47 degrees against Heze A, the planet experiences extreme seasonal changes, with seasons often lasting for several years at a time due to the planet's slow orbital speed around its parent sun. During winter, the New Medan caldera is plunged into snow, with acidic blizzards often seen battering against the colony's structures and driving most of the permanently-stationed inhabitants indoors. The first winter experienced on Avalon had shown the glowfruit trees abundant in the area are, in fact, evergreen, and instead of shedding their leaves and fruits instead change color of their leaves (and even their fruits) in response to the drops in temperature.

Surface
Much of Avalon is geologically active, with earthquakes and volcanoes creating hot springs which form steaming lakes. Although it is an uncommon sight, some of these lakes can grow to incredible size, rivaling that of even the Caspian. Despite the otherwise hostile implications set forth by the planet's activity, pockets of life containing fauna and flora exist in patches which surround these lakes, creating a network of oases which are shrouded in a purple hue brought along by the color of the Glowfruit Tree's leaves.

About 46% of Avalon is covered in water, with prominent underground aquifers making up another significant portion of the planet's water content. Approximately 35% of the water forms small seas across the planet, formed of saltwater containing potassium chloride. Small ice caps can also be found at the planet's poles. Several mountain ranges and highlands are also present on the surface, and routinely see varying amounts of snowfall all year round.

The dense population of Glowfruit Trees on Avalon can cause a natural phenomenon in which lights produced by their bioluminescence can be seen from low orbit on the dark side of the planet. This creates the illusion of city lights, despite there being no actual intelligent life native to the planet.