Sketchley's Statistics MRG - play stats here ABOUT LINKS logo_macross30th (4K) MAIN INDEX
By AARON SKETCHLEY ( 2019.12.15 Ver 2.4

Official Setting information is in darkgreen. Extended Universe information is in steelblue.

The Solar System - The Outer Solar System

  • Inner Solar System
  • Asteroid Belt

    5 AU
  • (P) Jupiter
    - Brangogne Satellite City
    - Miranda Satellite City
    - White Flora Satellite City
  • Io
  • Europa
    - Europa Base 7
  • Ganymede
    - Ganymede water and mining colony
  • Callisto
  • Jupiter Trojans
  • Centaur Planetoids
    6 AU
    9 AU
  • (P) Saturn
    - Reds Wood Satellite City
  • Mimas
  • Enceladus
  • Tethys
  • Dione
  • Rhea
  • Titan
  • Hyperion
  • Iapetus
    10 AU
  • Damocloid Asteroid
    15 AU
  • Chariklo
    19 AU
  • (P) Uranus
  • Miranda
  • Ariel
  • Umbriel
  • Titania
  • Oberon
  • Pholus
    30 AU
  • (P) Neptune
    - Grande Savoie Residential Area
  • Proteus
  • Triton
  • Nereid
  • Neptune trojans

  • Trans-Neptunian & Farthest Regions
  • Jupiter
    Jupiter is a giant planet with a mass one-thousandth of that of the Sun, but is two and a half times that of all the other planets in the Solar System combined. Jupiter is a gas giant, along with Saturn. Jupiter is primarily composed of hydrogen with a quarter of its mass being helium, although helium only comprises about a tenth of the number of molecules. It may also have a rocky core of heavier elements, but like the other giant planets, Jupiter lacks a well-defined solid surface. Because of its rapid rotation, the planet's shape is that of an oblate spheroid. The outer atmosphere is visibly segregated into several bands at different latitudes, resulting in turbulence and storms along their interacting boundaries. A prominent result is the Great Red Spot, a giant storm that is known to have existed since at least the 17th century when it was first seen by telescope. Surrounding Jupiter is a faint planetary ring system and a powerful magnetosphere.

    Jupiter Trojan Asteroids
    The Jupiter trojans, commonly called Trojan asteroids or just Trojans, are a large group of objects that share the orbit of the planet Jupiter around the Sun. Relative to Jupiter, each trojan librates around one of Jupiter's two stable Lagrangian points. Jupiter trojans are distributed in two elongated, curved regions around these Lagrangian points, with an average semi-major axis of about 5.2 AU.

    The total number of Jupiter trojans larger than 1 km in diameter is believed to be about 1 million. Like main-belt asteroids, Jupiter trojans form families. Jupiter trojans are dark bodies with reddish, featureless spectra.

    Centaur Planetoids
    Centaurs are small Solar System bodies with a semi-major axis between those of the outer planets. They have unstable orbits that cross or have crossed the orbits of one or more of the giant planets, and have dynamic lifetimes of a few million years. Centaurs typically behave with characteristics of both asteroids and comets.

    No centaur has been photographed up close, although there is evidence that Saturn's moon Phoebe may be a captured centaur. As of 2008, three centaurs have been found to display cometary comas: Chiron, 60558 Echeclus, and 166P/NEAT. Chiron and Echeclus are therefore classified as both asteroids and comets. Other centaurs, such as 52872 Okyrhoe, are suspected of showing cometary activity. Any centaur that is perturbed close enough to the Sun is expected to become a comet.


    The comet is unusual in that it suddenly undergoes an outburst. This causes the comet to brighten by 1 to 4 magnitudes. This happens with a frequency of 7.3 outbursts per year, fading within a week or two. The magnitude of the comet has been known to vary from 19th magnitude to 9th magnitude, a ten thousand-fold increase in brightness, during its brightest outbursts.


    Of objects listed as a centaur, Okyrhoe has the second smallest perihelion distance of a numbered centaur.

    2008 QD4

    Of numbered objects listed as a centaur, 2008 QD4 has the smallest perihelion distance.

    Saturn is a gas giant. Its interior is probably composed of a core of iron-nickel and rock (silicon and oxygen compounds). This core is surrounded by a deep layer of metallic hydrogen, an intermediate layer of liquid hydrogen and liquid helium, and finally outside the Frenkel line, a gaseous outer layer. Saturn has a pale yellow hue due to ammonia crystals in its upper atmosphere. Electrical current within the metallic hydrogen layer is thought to give rise to Saturn's planetary magnetic field. Saturn's magnetic field strength is around one-twentieth the strength of Jupiter's. The outer atmosphere is generally bland and lacking in contrast, although long-lived features can appear. Wind speeds on Saturn can reach 1,800 kmph, faster than on Jupiter, but not as fast as those on Neptune.

    Saturn has a prominent ring system that consists of nine continuous main rings and three discontinuous arcs, and that is composed mostly of ice particles, with a smaller amount of rocky debris and dust. Sixty-two moons are known to orbit Saturn, of which fifty-three are officially named. This does not include the hundreds of moonlets comprising the rings. Titan is larger than the planet Mercury, and is the only moon in the Solar System to have a substantial atmosphere.


    On 30 December 2005, when 13.1 AU from the Sun, a large chunk of Echeclus was observed to break off, causing a great cloud of dust. Astronomers have speculated this could have been caused by an impact or by an explosive release of volatile substances.

    Damocloid Asteroids
    Damocloids are minor planets that have Halley-family or long-period highly eccentric orbits typical of periodic comets such as Halley's Comet, but without showing a cometary coma or tail. Their average radius is 8 km. The albedos of four damocloids have been measured, and they are among the darkest objects known in the Solar System. Damocloids are reddish in color, but not as red as many Kuiper-belt objects or centaurs.
    Damocloids are believed to be nuclei of Halley-type comets that have lost all their volatile materials due to outgassing and become dormant. Such comets are believed to originate from the Oort cloud. Another strong indication of cometary origin is the fact that some damocloids have retrograde orbits, unlike any other minor planets.


    Damocles's orbit reaches from inside the aphelion of Mars to as far as Uranus. It seems to be in transition from a near-circular outer Solar System orbit to an eccentric orbit taking it to the inner Solar System. There is some speculation that Damocles may have a meteor shower associated with it on Mars from the direction of Draco.


    It is the second-known minor planet to have rings. Chiron's orbit was found to be highly eccentric, with perihelion just inside the orbit of Saturn and aphelion just outside the perihelion of Uranus. Chiron is probably a refugee from the Kuiper belt and will probably become a short-period comet in about a million years. Chiron is suspected to have two rings, similar to the better-established rings of Chariklo.

    The largest confirmed centaur. It is the smallest known object to have rings. Chariklo orbits within 0.09 AU of the 4:3 mean-motion resonance with Uranus. Chariklo's rings should disperse over a period of at most a few million years, so either they are very young, or they are actively contained by shepherd moons with a mass comparable to that of the rings.


    A centaur that grazes the orbit of Uranus.


    Centaurs are dark in colour, because their icy surfaces have darkened after long exposure to solar radiation and the solar wind. However, fresh craters excavate more reflective ice from below the surface. Asbolus is estimated to have an orbital half-life of about 860 kiloannum. Asbolus is currently classified as a SN centaur since Saturn is considered to control the perihelion and Neptune controls the aphelion.

    Uranus is similar in composition to Neptune, and both have different bulk chemical composition from that of the larger gas giants Jupiter and Saturn. Therefore, astronomers place them in a separate category called "ice giants". Uranus has the coldest planetary atmosphere in the Solar System, with a minimum temperature of 49 K, and has a complex, layered cloud structure, with water thought to make up the lowest clouds, and methane the uppermost layer of clouds. The interior of Uranus is mainly composed of ices and rock.

    Like the other giant planets, Uranus has a ring system, a magnetosphere, and numerous moons. The Uranian system has a unique configuration among those of the planets because its axis of rotation is tilted sideways, nearly into the plane of its revolution about the Sun. Its north and south poles therefore lie where most other planets have their equators. The wind speeds on Uranus can reach 250 m/s (900 kmph).

    At ultraviolet and visible wavelengths, Uranus's atmosphere is bland in comparison to the other giant planets, even to Neptune, which it otherwise closely resembles. One proposed explanation for this dearth of features is that Uranus's internal heat appears markedly lower than that of the other giant planets.

    In an eccentric orbit, with a perihelion less than Saturn's and aphelion greater than Neptune's. It is believed that Pholus originated in the Kuiper belt. It is quite red in color, for which it has been occasionally nicknamed "Big Red". It has shown no signs of cometary activity.


    Notable for its unusual orbit, which is highly eccentric and retrograde. It is one of twenty or so known minor planets in the Solar System that have a retrograde orbit. Dioretsa's orbit is otherwise similar to that of a comet. This has led to speculation that Dioretsa was originally an object from the Oort cloud.


    Nessus is an "SE object" because currently Saturn controls its perihelion and its aphelion is within the Kuiper belt.


    Currently Uranus controls Hylonome's perihelion and Neptune its aphelion.


    Amycus lies within 0.009 AU of the 3:4 resonance of Uranus.

    Neptune is the farthest planet from the Sun in the Solar System, and is the fourth-largest planet by diameter and the third-largest by mass. Among the gaseous planets in the Solar System, Neptune is the most dense. Neptune is slightly more massive than its near-twin Uranus. Neptune is similar in composition to Uranus. Astronomers sometimes categorise Uranus and Neptune as "ice giants" to emphasise this distinction from Jupiter and Saturn. The interior of Neptune is primarily composed of ices and rock.

    Neptune's atmosphere has active and visible weather patterns. These weather patterns are driven by the strongest sustained winds of any planet in the Solar System, with recorded wind speeds as high as 2,100 kmph. Because of its great distance from the Sun, Neptune's outer atmosphere is one of the coldest places in the Solar System, with temperatures at its cloud tops approaching 55 K.

    Neptune's weather is characterised by extremely dynamic storm systems. Most of the winds on Neptune move in a direction opposite the planet's rotation. The general pattern of winds showed prograde rotation at high latitudes vs. retrograde rotation at lower latitudes. Because of seasonal changes, the cloud bands in the southern hemisphere of Neptune have been observed to increase in size and albedo. The long orbital period of Neptune results in seasons lasting forty years.

    Neptune Trojan Asteroids
    Neptune trojans are bodies in orbit around the Sun that orbit near one of the stable Lagrangian points of Neptune. They therefore have approximately the same orbital period as Neptune and follow roughly the same orbital path. The discovery of 2005 TN53 in a high-inclination (>25°) orbit was significant, because it suggested a "thick" cloud of trojans, which is indicative of freeze-in capture instead of in situ or collisional formation. It is suspected that large (radius ≈ 100 km) Neptune trojans could outnumber Jupiter trojans by an order of magnitude.

    The orbits of Neptune trojans are highly stable; Neptune may have retained up to 50% of the original post-migration trojan population over the age of the Solar System. The original population of trojans probably contained many objects on dynamically unstable orbits, and the current trojan population continues to contribute centaurs. On the other hand, a trojan on a stable orbit need not be primordial.

    The first four discovered Neptune trojans have similar colors. They are modestly red, slightly redder than the gray Kuiper belt objects, but not as extremely red as the high-perihelion cold classical Kuiper belt objects. This is similar to the colors of the blue lobe of the centaur color distribution, the Jupiter trojans, the irregular satellites of the gas giants, and possibly the comets, which is consistent with a similar origin of these populations of small Solar System bodies.

    2007 RW10

    A temporary quasi-satellite of Neptune. Prior to the quasi-satellite dynamical state, 2007 RW10 was an L5 trojan, and it will go back to that state soon after leaving its current quasi-satellite orbit. Its orbital inclination is the largest among known Neptune co-orbitals. It is also possibly the largest known object trapped in the 1:1 mean-motion resonance with any major planet.

    1999 OX3

    A TNO in a Centaur-like orbit.

  • Wikipedia and the numerous contributors to it
  • The Macross Compendium's Atlas
  • The UNSDB's Colonies and Bases list by Daniel Henwood

  • © Aaron Sketchley