Ixo System

Ixo, planets, moons and dwarf planets (true color, size to scale, distance not to scale)

## Planetary system

### Semi-major axis of outern known planet

* 38.3 AU
* 5.7296 bill. km
* 3.5602 bill. mi

## Populations

### Known planets

* Painia
* Emeron
* Ratera
* Yuter
* Theania
* Vyria
* Nadrinus
* Munvides
* Chiistea
* Iucarro

### Known dwarf planets

* Curio
* Ora
* Erecurni
* Mefitis
* Labal
* Cifercu
* Atuve
* Tustis
* Minaena
* Xiongwei
* Ushris

### Known natural satellites

38+ (25+ planetary,13+ minor planetary)

The **Ixo System** is the gravitationally bound system of Ixo and the objects that orbit the star. The largest of such objects are the ten planets, in order from Ixo: six terrestrial planets named Painia, Emeron, Ratera, Yuter, Theania, and Vyria, three gas giants named Nadrinus, Munvides, and Chiistea, and one ice giant named Iucarro. The terrestrial planets have a definite surface and are mostly made of rock and metal. The gas giants are made mostly of hydrogen and helium, while the ice giant is made mostly out of water, ammonia, and methane. In some texts, these terrestrial planets and gas giants are referred to as the inner Ixo System and outer Ixo system respectively.

The Ixo System was formed around 4.6 billion years ago from the gravitational collapse of a giant interstellar molecular cloud. Over time, this molecular cloud formed Ixo and a protoplanetary disk that gradually formed the planets and other objects. This is the reason why all ten planets have an orbit that lies near the same plane. Eight of the planets and nine of the possible dwarf planets have natural satellites or moons orbiting around them.

There are an unknown number of smaller dwarf planets and innumerable small bodies orbiting Ixo. These objects are primarily distributed around the asteroid belt that lies between the orbits of Vyria and Nadrinus, the Seyler belt, the scattered disc that both lies beyond Iucarro's orbit and at even further reaches of the Ixo System which they would be classified as an extreme trans-Iucarroan object. There is consensus between astronomers that these eleven objects are considered dwarf planets: the asteroids Curio and Ora, the Syler-belt objects Erecurni, Atuve, Cifercu, Mefitis, and Labal, and the scattered-disc objects Minaena, Xiongwei, Tustis, and Ushris. Many small-body objects like comets, centaurs and interplanetary dust clouds, freely travel between regions of the Ixo System.

## Inner Ixo System

The inner Ixo System is the region comprising the terrestrial planets and the asteroid belt. Comprised primarily of silicates and metals like iron, the objects of the inner Ixo System are relatively close to Ixo; the entire radius of this regions is less than the distance between the orbits of Nadrinus and Munvides.

### Inner planets

The six terrestrial or inner planets have dense, rocky compositions, few or no moons, and no ring systems. They are composed mainly of silicates - which form their crusts and mantles - and metals such as iron and nickel which form their cores. Four of the six inner planets have atmospheres thick enough to generate weather; all have impact craters and tectonic surface features, such as rift valleys and volcanoes.

#### Painia

*Main article: Painia*

Painia (0.161-0.205 AU (24.0-30.6 million km; 14.9-19.0 million mi) from Ixo) is the closest planet to Ixo. The second smallest planet in the Ixo System (0.313 MEarth), Painia has no natural satellites nor an atmosphere. The dominant features across Painia's surface are mountain ranges and craters.

#### Emeron

*Main article: Emeron*

Emeron (0.271-0.283 AU (40.5-42.3 million km; 25.1-26.2 million mi) from Ixo) is the smallest planet (0.208 MEarth) in the Ixo System, and second from Ixo. Emeron has no atmosphere and lacks any natural satellites. Despite being smaller than the planet Painia, Emeron is denser.

#### Ratera

*Main article: Ratera*

Ratera (0.388-0.392 AU (58.0-58.6 million km; 36.0-36.4 million mi) from Ixo) is the third smallest planet (0.921 MEarth) in the Ixo System, and third from Ixo. It is known to have geological activity and is the only known place in the universe to host life. It is unique in being one of two celestial bodies in the Ixo System to possess liquid water on its surface and is the only known planet to have observed plate tectonics. Its atmosphere differs greatly due to the presence of life on its surface, containing more than 23% free oxygen. It has one natural satellite, Auter.

#### Yuter

*Main article: Yuter*

Yuter (0.673-0.687 AU (100.6-102.7 million km; 62.5-63.8 million mi) from Ixo) is the fourth planet from Ixo. It is large in size (2.91 MEarth), being similar in size to Vyria and second largest terrestrial planet in the Ixo System. The surface of Yuter consists mainly of highlands, with an average elevation of 10.3 km. Yuter has a thin atmosphere and has one natural satellite, Zuturn, which is unique in being the only moon in the Ixo system to possess an atmosphere, and the only celestial body other than Ratera to possess liquid water on its surface. Unlike Ratera, it is uncertain if life exists on Zuturn above the possible microbial level. Zuturn is also the largest moon compared to its orbital parent of any planet in the Ixo System, being around 25% the size of Yuter.

#### Theania

*Main article: Theania*

Theania (0.908-0.987 AU (135.8-147.6 million km; 84.4-91.7 million mi) from Ixo) is the third largest of the terrestrial planets (1.62 MEarths) and fourth from Ixo. It has a thin atmosphere similar to Yuter's. It's surface does not have very much variation, with highlands of a maximum height of 4.19 km and lowlands of 0.136 km. It has one natural satellite, Xezeon.

#### Vyria

*Main article: Vyria*

Vyria (1.5-1.8 AU (224.4-269.2 million km; 139.4-167.2 million mi) from Ixo) and is the sixth planet from Ixo, as well as the largest terrestrial planet (3.07 MEarths) in the Ixo System. It has a thicker atmosphere than the other planets with the exception of Ratera, which an atmosphere made mainly of carbon dioxide. Vyria is also relatively active, possessing weather, vyriaquakes, and volcanic eruptions It has two natural satellites, the smallest of which is Gainia, and the largest is Thouros.

### Asteroid belt

Asteroids except for the two largest, Curio and Ora, are classified as small Ixo System bodies and are comprised of mainly silicates and metallic minerals, with some ice. They range from a few meters to hundreds of kilometers in size.

The asteroid belt occupies the orbit between Vyria and Nadrinus, between around 1.8 and 2.3 AU (269 and 344 million km; 167 and 213 million mi) from Ixo. It is thought to be remnants from the Ixo System's formation that failed to coalesce because of the gravitational interference of Nadrinus. The asteroid belt is assumed to contains tens if not hundreds of thousands of celestial bodies greater than one km in diameter. Despite this, the region is sparsely populated.

#### Curio & Ora

*Main articles: Curio & Ora*

Curio and Ora are dwarf planets that orbit within the asteroid belt. They are the only dwarf planets the orbit completely within the orbit of Iucarro. Both Curio and Ora differ from other asteroids due to their larger size, and rounded shape. Curio (1.91-1.92 AU (285.7-287.2 km; 177.5-178.4 mi)) has a diameter of around 1,798 km, and Ora (2.07-2.08 AU (309.6-311.1 km; 192.3-193.3 mi)) has a diameter of around 1,670 km.

#### Cita & Salibe

*Main articles: Cita & Salibe*

Cita and Salibe are two major asteroids in the asteroid belt that are smaller than the dwarf planets Curio and Ora, but larger than other asteroids.

## Outer Ixo System

The outer region of the Ixo System is home to the giant planets and their large moons. Centaurs and comets also orbit in this region. Due to their greater distance from Ixo, the solid objects in the outer Ixo System contain higher proportions of water, ammonia, and methane than those of the inner Ixo System because of the lower temperatures allow these compounds to remain solid.

### Outer Planets

The four outer planets, also called gas giants, collectively make up around 99% of the mass known to orbit Ixo. Nadrinus is more than 100 times the mass of Ratera and consists primarily of hydrogen and helium, Iucarro is also around 100 times the mass of Ratera, but contains much more water, ammonia, and methane, as such it has been suggested the Iucarro be its own category known as a ice giant. The smaller of the gas giants, Munvides and Chiistea combined around 50 times the mass of Ratera and contains mainly hydrogen and helium. All four gas giants possess rings, however only Chiistea's are more easily visible from Ratera.

#### Nadrinus

*Main article: Nadrinus*

Nadrinus (2.59-2.59 AU (387.4-388.1 million km; 240.7-241.1 million mi) from Ixo) is the largest planet (95.4Earths) in the Ixo System and is sixth from Ixo. It is a gas giant made primarily of hydrogen and helium, and is uniquely colored. It has a blue northern pole due to the presence of methane whereas the southern pole is mainly yellow due to the upper most clouds containing helium and partially blue due to methane. The reason for the red color of the rest of the planet's clouds is relatively uncertain, though it possibly has to deal with the presence of ammonia or hypothetically red phosphorus. The brown equatorial ring of clouds is likely caused by ammonia or even water vapor or hydrocarbons.

Nadrinus has a large number of moons, with eight major moons: Liotis, Eloumia, Egion, Orilia, Ethea, Yiclite, Treinope, and Monroria.

#### Munvides

*Main article: Munvides*

Munvides (5.58-6.17 AU (834.7-923.0 million km; 518.6-573.5 million mi) from Ixo) is the second gas giant from Ixo and the smallest gas giant (16.2Earths) in the Ixo System. Unlike the more colorful Nadrinus and Chiistea, Munvides is almost solely white and grey in color which is caused by helium and hydrogen in the atmosphere. Both its southern and northern poles are faintly blue which is caused by methane gas.

Munvides, like the other gas giants has many moons. It has four major moons: Lupi, Cibadus, Tivionus and Tolichi.

#### Chiistea

*Main article: Chiistea*

Chiistea (19.6-21.7 AU (2.932-3.246 billion km; 1.821-2.017 billion mi) from Ixo) is the third gas giant from Ixo and is the third biggest planet (30.9Earths). Chiistea is primarily yellow in color with bands of orange its atmosphere. These colors are caused by the presence of helium and ammonia. The most prominent feature of Chiistea is its rings which contain ice, iron and silicate.

It has five major moons: Udorix, Ubos, Bineter, Etharth and Canus, though it has many minor moons.

#### Iucarro

*Main article: Iucarro*

Iucarro (34.4-38.3 AU (5.146-5.729 billion km; 3.197-3.560 billion mi) from Ixo) is the furthest planet from Ixo and the second largest planet but the heaviest (100Earths) in the Ixo System. Iucarro is an ice giant, made primarily of ice as well gasses, mainly methane as well as helium and hydrogen.

Iucarros has three major moons: Keivis, Chunides and Verta, as well as many minor moons.

### Centaurs

The centaurs are icy comet-like bodies whose orbits have semi-major axes greater than Nadrinus' (2.59 AU (387 million km; 240 million mi)) and less than Iucarro's (36.3 AU (3.93 billion km; 2.44 billion mi)). These are former Seyler belt objects that were gravitationally perturbed closer to Ixo by the outer planets, and are expected to become comets or be ejected from the Ixo System. Most centaurs are inactive, however some show comet-like activity, such as the first centaur discovered, 2003 Horta.

## Comets

Comets are small Ixo System bodies, typically only a few kilometers across, composed mostly if not entirely of ices. They have highly eccentric orbits, generally a perihelion within the orbits of the inner planets and an aphelion in the Seyler belt. When a comet enters the Inner Ixo System, its proximity to Ixo causes its icy surface to sublimate and ionize, creating a coma: a long tail of gas and dust often visible to the naked eye.

## Trans-Iuccaroan region

Beyond the orbit of Iuccaro lies the area of the "trans-Iuccaroan region", with the doughnut-shaped Seyler belt, home of Erecurni and several other dwarf planets, and an overlapping disc of scattered objects which reaches out much further than the Seyler belt and is tilted towards the plane of the Ixo System. The entire region consists of thousands of small worlds - with the largest having a diameter only a sixth that of Ratera and a mass far smaller than that of Auter - comprised mainly of rock and ice.

### Seyler belt

The Seyler belt is a great ring of debris similar to the asteroid belt but consisting mainly of objects comprised primarily of ice. It extends between around 40 and 65 AU (5.98 and 9.72 billion km; 3.71 and 6.04 billion mi) from Ixo. It is comprised mainly of small Ixo System bodies, although the largest few are large enough to be classified as dwarf planets. There are estimated to be somewhere 125,000 Seyler belt objects with a diameter of more than 50 km (30 mi), but the total mass of the Seyler belt is likely only a tenth or even a hundredth of the mass of Ratera. Many Seyler belt objects have satellites, and most have elliptical orbits.

### Scattered disc

The scatter disc, which overlaps with the Seyler belt but extends out to near 500 AU, is thought to be the source of some comets. Scattered disc objects are thought to have been perturbed into erratic orbits by the gravitational influence of Iuccaro's early outward migration. Most scattered disc objects (SDOs) have perihelia within the Seyler belt but aphelia far beyond it (a handful more than 150 AU from Ixo). SDOs' orbits can also be heavily inclined, with inclinations above 40° from the elliptical plane.

## Farthest regions

The point at which the Ixo System ends, and interstellar space begins is not precisely defined because its outer boundaries are shaped by two forces, the ixoar wind and Ixo's gravity. The limit of the ixoar wind's influence is around six times Erecurni's distance from Ixo; this *heliopause*, the outer boundary of the heliosphere, is considered the beginning of the interstellar medium. Ixo's Hill sphere, the effective range of its gravitational dominance, is thought to extend up to a thousand times farther and encompasses the hypothetical Oort Cloud.

### Edge of the heliosphere

Ixo's ixoar-wind bubble, the heliosphere, a region of space dominated by Ixo, has its boundary at the *termination shock*, which is roughly 90-100 AU from Ixo upwind of the interstellar medium and roughly 250 AU from Ixo downwind. Here the ixoar wind collides with the interstellar medium and dramatically slows, condenses, and becomes more turbulent, forming a great oval structure known as the *heliosheath*. This structure has been hypothesized to look and act similar to a comet's tail, extending outwards for another 40 AU upwind but tailing many times that distance downwind.

### Oort cloud

The Oort cloud is a hypothesized spherical cloud containing trillions of small icy objects that is thought to be the origin of all long-period comets and to surround the Ixo System at roughly 50,000 AU (roughly 1 light year (ly)) from Ixo, and possibly as far as 10,000 AU (1.87 ly). It is thought to be composed of comets that were ejected from the inner Ixo System by gravitational interactions with the outer planets. Oort cloud objects move very slowly, and can be perturbed by infrequent events, such as collisions, gravitational effects of a passing star, or the galactic tide.

### Boundaries

Much of the Ixo System is unknown. Ixo's gravitational field is estimated to dominate the forces of surrounding stars out to about two light years (125,000 AU). Lower estimates for the radius of the Oort cloud, by contrast, do not place it further than 50,000 AU.

## Location

Within 10 lightyears of Ixo, there are a total of eight stars, the closest of which is Zeta Navolis, which lays about 1.73 lightyears away from Ixo. The next two closest stars are Theta Alicus and Eta Alicus, being 3,03 lys and 3.05 lys away from Ixo respectively. The remaining five stars are beyond 8 lys away from Ixo, which, in order from closest to furthest are: Eta Sinon, Gamma Callineria, Alpha Pentagorus, Delta Paris, and Zeta Testudo.

Since ancient times, several civilizations have looked to the stars for guidance. The most notable stars in the sky used for celestial navigation are Polaris and Australis, the North Star and South Star respectively. Many also saught knowledge from the sky, forming constellations. In Western astrology, there are a total of 34 constellations, 16 in the northern hemisphere, and 18 in the southern hemisphere. Constellations were often named after animals, important mythological peoples and creatures, as well as general shapes or objects that astrologers believed the stars to resemble when connecting lines between them.

For more astronomical and astrological information, see *List of Constellations*