Casara System

The Casara system is the star system home to the planet of Aesthetica, consisting of four terrestrial worlds and two gaseous worlds, located within the Outer Rim territories.

## Discovery and Exploration

In the year 1950, the Casara system was colonised by a band of Chiss exiles who had gone through thousands of years of universe-spanning travel to reach a safe destination to start anew aboard large, space-faring hotels, eventually landing on the third planet of the system, Aesthetica, to begin forging their society. By 2318, Aesthetica had became a successful and prominent society, expanding its influence to three other worlds in the system; the terrestrial worlds of Magart and Klusos, and the gas giant Yuqui.

## Structure and Composition

The principle component of Casara system is the G2 main sequence star Casar, which contains over 99% of the Casara system's mass and dominates the system gravitationally. Casar's two giant planets, the gaseous Yuqui and Gyuminatrix, account for the 99% of the remaining mass, with the remaining objects, including the four terrestrial planets Magart, Klusos, Aesthetica and Remus, as well as asteroids, comets, and moons, together compromise 0.003% of the entire star system's mass.

Most large objects in the Casara system orbit Casar along the ecliptic plane, including Aesthetica, with planets orbiting very close to the ecliptic, whereas comets, asteroids and objects within the Kru'uja Belt are frequently at greater angles to it. All the planets, asteroids and other objects in the Casara system with the exception of Remus and the Yukari Comet, orbit Casar in the same direction Casar rotates (counter-clockwise, as viewed from Aesthetica's Great Pole).

Most planets in the Casara system possess secondary systems of their own, being orbited by moons, and in the case of Gyuminatrix, rings (thin bands of tiny particles and asteroids that orbit the planet in unison). Most of the largest natural satellites are in synchronous rotation, meaning they always face their parent body.

Following Kepler's laws, each object in orbit of Casar travels along an ellipse with Casar at one focus. Objects closer to Casar orbit much quicker, as they are greater affected by Casar's gravitational pull. On an elliptical orbit, a body's distance from Casar varies over the course of its year. A body's closest approach to Casar is called its pericason, whereas its most distant point from the Sun is called its aphicason.

Although Casar dominates the system by mass, it accounts for only about 3% of the angular momentum. The planets, dominated by Yuqui, account for most of the rest of the angular momentum due to the combination of their mass, orbit, and distance from Casar, with a possibly significant contribution from comets.

Casar, which comprises nearly all the matter in the Casara system, is composed of roughly 97% hydrogen and helium. Yuqui and Gyuminatrix, which comprise nearly all the remaining matter, are also primarily composed of hydrogen and helium, as well as tibanna. A composition gradient exists in the Casara sytstem, created by heat and light pressure from Casar; those objects closer to Casar, which are more affected by heat and light pressure, are composed of elements with high melting points. Objects farther from Casar are composed largely of materials with lower melting points. The boundary in the Solar System beyond which those volatile substances could condense is known as the frost line, and it lies at roughly 6 AU from Casar.

The objects of the inner Casara system are composed mostly of rock, the collective name for compounds with high melting points, such as silicates, iron or nickel, that remained solid under almost all conditions in the protoplanetary nebula. Yuqui and Gyuminatrix are composed mainly of gases, the astronomical term for materials with extremely low melting points and high vapour pressure, such as hydrogen, helium, tibanna and neon, which were always in the gaseous phase in the nebula. Ices, like water, methane, ammonia, hydrogen sulfide, and carbon dioxide, have melting points up to a few hundred kelvins. They can be found as ices, liquids, or gases in various places in the Casara system, whereas in the nebula they were either in the solid or gaseous phase. Icy substances comprise the majority of the satellites of the two giant planets, and the numerous small objects that lie beyond Remus's orbit. Together, gases and ices are referred to as volatiles.

### Distances and scales

The distance between Casar and Aesthetica is 1.56 Astronomical Units (AU), with Magart being the closest to Casar (0.48 AU), and Remus being the furthest away (44 AU). Klusos, the second planet closest to Casar, is 0.84 AU away, and the two gas giants, Yuqui and Gyuminatrix, are 17 and 31 AU away respectively. The Kru'uja Belt, further out from Casar than even Remus, spans 0.0032 AU in length on average, and at its closest point, is 79 AU away from Casar. At its pericason, the Yukari Comet is 7 AU away from Casar, and at its aphicason, Yukari is 107 AU away.

## Formation

The Casara system formed 4.792 billion years ago from the gravitational collapse of a region within a large molecular cloud. This initial cloud was likely several light-years across and probably birthed several stars, including the neighbouring Greyta and Alau'coganu systems.  As is typical of molecular clouds, this one consisted mostly of hydrogen, with some helium and tibanna, and small amounts of heavier elements fused by previous generations of stars. As the region that would become the Casara system, known as the pre-casara nebula, collapsed, conservation of angular momentum caused it to rotate faster. The centre, where most of the mass collected, became increasingly hotter than the surrounding disc. As the contracting nebula rotated faster, it began to flatten into a protoplanetary disc with a diameter of roughly 230 AU and a hot, dense protostar at the centre. The planets formed by accretion from this disc, in which dust and gas gravitationally attracted each other, coalescing to form ever larger bodies. Hundreds of protoplanets may have existed in the early Solar System, but they either merged or were destroyed, leaving the planets such as Magart, Yuqui, Gyuminatrix, Klusos and Remus, dwarf planets like Aesthetica, and leftover minor bodies.

## Casar

Casar is the Casara system's star and by far its most massive component. Its large mass produces temperatures and densities in its core high enough to sustain nuclear fusion of hydrogen into helium, making it a main-sequence star. This releases an enormous amount of energy, mostly radiated into space as electromagnetic radiation peaking in visible light.

Casar is a G2-type main-sequence star. Hotter main-sequence stars are more luminous. Casar's temperature is intermediate between that of the hottest stars and that of the coolest stars. Stars brighter and hotter than Casar are rare, whereas substantially dimmer and cooler stars, known as red dwarfs, make up 89% of the stars in the known galaxies.

Casar is a population I star; it has a higher abundance of elements heavier than hydrogen and helium ("metals" in astronomical parlance) than the older population II stars. Elements heavier than hydrogen and helium were formed in the cores of ancient and exploding stars, so the first generation of stars had to die before the Universe could be enriched with these atoms. The oldest stars contain few metals, whereas stars born later have more. This high metallicity is thought to have been crucial to Casar's development of a planetary system because the planets form from the accretion of "metals".

## Inner Casara System

### Magart

Magart is the closest planet to Casar (0.48 AU away) and is the second smallest planet in the Casar system. It is a barren, crater-topped rocky world with lava-filled trenches spanning the surface, and a thin, tenuous and toxic atmosphere. Magart has no natural satellites, but is home to an Aesthetican mining colony that includes a space station orbiting the world. At the bottom of its craters, and at night, the temperatures of Magart are below freezing, though at the Casar-warmed surface, temperatures rise to well over 300°C.

### Klusos

Klusos is the second closest planet to Casar (0.84 AU away), and is the largest of the terrestrial planets in the Casar system. It is a purple world smothered by a thick, toxic atmosphere that traps the heat of Casar within the planet, raising temperatures to over 120°C on the surface. Despite these temperatures, Klusos has lakes and oceans, though not of water, but of sulphuric acid. It has one natural satellite, a misshapen, rocky moon known as Aerstos, and is home to an Aesthetican mining colony built to survive under the harsh conditions.

### Aesthetica

Aesthetica is the third closest planet to Casar (1.56 AU away), and is the smallest planet in the Casar system, and is classified as a dwarf planet. A rocky world enriched with water, icy caps, plant and animal life, Aesthetica is home to millions of species. Its atmosphere is thick, containing over 23% free oxygen. It has two natural satellites and one made by the life it cultivates; the moons of Krasnada and Pelero, and Fogor Battlestation.

## Outer Casara System

### Yuqui

Yuqui is the fourth closest planet to Casar (17 AU away), and is the largest planet in the Casar system. A gas giant, Yuqui is mostly, if not all, atmosphere, containing oxygen, hydrogen, neon, tibanna, and helium. Yuqui has several natural satellites and is also home to an Aesthetican mining colony floating in the breathable zone of Yuqui's atmosphere, mining and refining the tibanna gas for use in Aesthetican hyperdrives. Yuqui commonly has large storms, and is also known to rain.

### Gyuminatrix

Gyuminatrix is the second largest planet in the Casara system, and the fifth closest to Casar (31 AU away). Unlike its bigger gaseous brother Yuqui, Gyuminatrix is toxic and much stormier, rendering it unsuitable for Aesthetican colonies. It also produces tibanna, and contains hydrogen, neon and helium, as well as several other gases. Around it is a stunning ring system, with several moons on either side of it.

### Remus

Remus is the furthest planet away from Casar (44 AU), and is the second largest terrestrial planet. Unlike the other planets, it orbits clockwise relative to Aesthetica's Great Pole, and is thus slowly tearing itself apart. The world has no atmosphere, and is frosty and rocky with deep trenches and jagged, lava-filled holes where chunks of the planet had been torn out by gravity. It is estimated that in a few million years, Remus will be nothing more than another asteroid belt.

### Kru'uja Belt

The Kru'uja belt is a large asteroid belt beginning 79 AU away from Casar. It is home to billions of asteroid-sized particles as well as other minor bodies too small to be considered a even dwarf planet. Its sheer size and presence makes hyperspace travel to adjacent star systems from Casar impossible, and so starships must travel longer routes to avoid it.

## Trans-Kru'ujan Objects

### The Yukari Comet

While the Yukari Comet can come as close as 7 AU away from Casar, it is believed it originated from beyond the Kru'uja Belt, some 100 AU away from Casar. An icy comet travelling at extremely high velocities, it takes nearly 135 years for it to complete its orbit, leaving a bright trail of ice and rock along its path.