Small objects in the Solar System ESA25188647

Kuiper belt plot objects of outer solar system

Solar System belts are

asteroid An asteroid is a minor planet—an object larger than a meteoroid that is neither a planet nor an identified comet—that orbits within the Solar System#Inner Solar System, inner Solar System or is co-orbital with Jupiter (Trojan asteroids). As ...

and

comet A comet is an icy, small Solar System body that warms and begins to release gases when passing close to the Sun, a process called outgassing. This produces an extended, gravitationally unbound atmosphere or Coma (cometary), coma surrounding ...

belts that orbit the

Sun The Sun is the star at the centre of the Solar System. It is a massive, nearly perfect sphere of hot plasma, heated to incandescence by nuclear fusion reactions in its core, radiating the energy from its surface mainly as visible light a ...

in the

Solar System The Solar SystemCapitalization of the name varies. The International Astronomical Union, the authoritative body regarding astronomical nomenclature, specifies capitalizing the names of all individual astronomical objects but uses mixed "Sola ...

in interplanetary space. The Solar System belts' size and placement are mostly a result of the Solar System having four

giant planet A giant planet, sometimes referred to as a jovian planet (''Jove'' being another name for the Roman god Jupiter (mythology), Jupiter), is a diverse type of planet much larger than Earth. Giant planets are usually primarily composed of low-boiling ...

Jupiter Jupiter is the fifth planet from the Sun and the List of Solar System objects by size, largest in the Solar System. It is a gas giant with a Jupiter mass, mass more than 2.5 times that of all the other planets in the Solar System combined a ...

Saturn Saturn is the sixth planet from the Sun and the second largest in the Solar System, after Jupiter. It is a gas giant, with an average radius of about 9 times that of Earth. It has an eighth the average density of Earth, but is over 95 tim ...

Uranus Uranus is the seventh planet from the Sun. It is a gaseous cyan-coloured ice giant. Most of the planet is made of water, ammonia, and methane in a Supercritical fluid, supercritical phase of matter, which astronomy calls "ice" or Volatile ( ...

and

Neptune Neptune is the eighth and farthest known planet from the Sun. It is the List of Solar System objects by size, fourth-largest planet in the Solar System by diameter, the third-most-massive planet, and the densest giant planet. It is 17 t ...

far from the sun. The giant planets must be in the correct place, not too close or too far from the sun for a system to have Solar System belts.

Formation

The Solar System belts were formed in the

formation and evolution of the Solar System There is evidence that the formation of the Solar System began about 4.6 billion years ago with the gravitational collapse of a small part of a giant molecular cloud. Most of the collapsing mass collected in the center, forming the Sun, while ...

. The Grand tack hypothesis is a model of the unique placement of the giant planets and the Solar System belts. Most

s found outside our Solar System,

exoplanet An exoplanet or extrasolar planet is a planet outside the Solar System. The first confirmed detection of an exoplanet was in 1992 around a pulsar, and the first detection around a main-sequence star was in 1995. A different planet, first det ...

s, are inside the

snow line The climatic snow line is the boundary between a snow-covered and snow-free surface. The actual snow line may adjust seasonally, and be either significantly higher in elevation, or lower. The permanent snow line is the level above which snow wil ...

, and are called

Hot Jupiter Hot Jupiters (sometimes called hot Saturns) are a class of gas giant exoplanets that are inferred to be physically similar to Jupiter (i.e. Jupiter analogue, Jupiter analogues) but that have very short orbital periods (). The close proximity to t ...

s. Thus in normal planetary systems giant planets form beyond snow line and then migrated towards the star. A small percent of giant planets migrate far from the star. In both types of migrations, the Solar System belts are lost in these planetary migrations. The Grand tack hypothesis explains how in the Solar System giant planets migrated in unique way to form the Solar System belts and near circular orbit of planets around the Sun. The Solar System's belts are one key parameters for a Solar System that can support complex life, as circular orbits are a parameter needed for the

Habitable zone for complex life A Habitable Zone for Complex Life (HZCL) is a range of distances from a star suitable for complex aerobic life. Different types of limitations preventing complex life give rise to different zones. Conventional habitable zones are based on compati ...

Solar System belts

The asteroid and comet belts orbit the Sun from the inner rocky planets into outer parts of the Solar System, interstellar space. An

astronomical unit The astronomical unit (symbol: au or AU) is a unit of length defined to be exactly equal to . Historically, the astronomical unit was conceived as the average Earth-Sun distance (the average of Earth's aphelion and perihelion), before its m ...

, or AU, is the distance from Earth to the Sun, which is approximately 150 billion meters (93 million miles). Small Solar System objects are classified by their orbits: * Main

Asteroid belt The asteroid belt is a torus-shaped region in the Solar System, centered on the Sun and roughly spanning the space between the orbits of the planets Jupiter and Mars. It contains a great many solid, irregularly shaped bodies called asteroids ...

(main belt), between Mars and Jupiter, in near circular orbit, 2.2 to 3.2 AU ** Hungaria asteroids, small group, 1.78 to 2.00 AU **

Alinda asteroid The Alinda asteroids are a dynamical group of asteroids with a semi-major axis of about 2.5 AU and an orbital eccentricity approximately between 0.4 and 0.65.Hilda asteroid small group just inside Jupiter, 4.0 AU *

Kuiper belt The Kuiper belt ( ) is a circumstellar disc in the outer Solar System, extending from the orbit of Neptune at 30 astronomical units (AU) to approximately 50 AU from the Sun. It is similar to the asteroid belt, but is far larger—20 times ...

large belt, 43 to 64.5 AU *

Scattered disc The scattered disc (or scattered disk) is a distant circumstellar disc in the Solar System that is sparsely populated by icy small Solar System bodies, which are a subset of the broader family of trans-Neptunian objects. The scattered-disc obj ...

small group, 21.5 to 215 AU * Sednoid (inner Oort cloud objects) small group of four or more, high elliptical orbits, 47.8 to 80 AU *

Extreme trans-Neptunian object An extreme trans-Neptunian object (ETNO) is a trans-Neptunian object orbiting the Sun well beyond Neptune (30 AU) in the outermost region of the Solar System. An ETNO has a large semi-major axis of at least 150–250 AU. The orbits of ET ...

s 150 to 250 AU * Hills cloud a large hypothetical circumstellar disc

Planets

Solar System planets 10 largest Trans-Neptunian objects Solar System

planet A planet is a large, Hydrostatic equilibrium, rounded Astronomical object, astronomical body that is generally required to be in orbit around a star, stellar remnant, or brown dwarf, and is not one itself. The Solar System has eight planets b ...

s and

dwarf planet A dwarf planet is a small planetary-mass object that is in direct orbit around the Sun, massive enough to be hydrostatic equilibrium, gravitationally rounded, but insufficient to achieve clearing the neighbourhood, orbital dominance like the ...

s listed for distances comparison to belts. The Solar System planets all orbit in near circular orbits.
Planets: * Mercury 0.39 AU *

Venus Venus is the second planet from the Sun. It is often called Earth's "twin" or "sister" planet for having almost the same size and mass, and the closest orbit to Earth's. While both are rocky planets, Venus has an atmosphere much thicker ...

0.72 AU *Earth 1 AU *

Mars Mars is the fourth planet from the Sun. It is also known as the "Red Planet", because of its orange-red appearance. Mars is a desert-like rocky planet with a tenuous carbon dioxide () atmosphere. At the average surface level the atmosph ...

1.52 AU *Jupiter 5.2 AU *Saturn 9.54 AU *Uranus 19.2 AU *Neptune 30.06 AU
Dwarf planets:

Dwarf planet A dwarf planet is a small planetary-mass object that is in direct orbit around the Sun, massive enough to be hydrostatic equilibrium, gravitationally rounded, but insufficient to achieve clearing the neighbourhood, orbital dominance like the ...

s, other than Ceres, are plutoids that have elliptical orbits: * Ceres, 2.8 AU in the asteroid belt *

Orcus Orcus was a god of the underworld, punisher of broken oaths in Etruscan and Roman mythology. As with Hades, the name of the god was also used for the underworld itself. Eventually, he was conflated with Dis Pater and Pluto. A temple to Orcus ma ...

39.4 AU, Trans-Neptunian-Kuiper belt object *

Pluto Pluto (minor-planet designation: 134340 Pluto) is a dwarf planet in the Kuiper belt, a ring of Trans-Neptunian object, bodies beyond the orbit of Neptune. It is the ninth-largest and tenth-most-massive known object to directly orbit the Su ...

39 AU, Kuiper belt (a planet until 2006) *

Haumea Haumea ( minor-planet designation: 136108 Haumea) is a dwarf planet located beyond Neptune's orbit. It was discovered in 2004 by a team headed by Mike Brown of Caltech at the Palomar Observatory, and formally announced in 2005 by a team heade ...

43 AU, Kuiper belt *

Makemake Makemake ( minor-planet designation: 136472 Makemake) is a dwarf planet and the largest of what is known as the classical population of Kuiper belt objects, with a diameter approximately that of Saturn's moon Iapetus, or 60% that of Pluto. It ...

45.8 AU, Kuiper belt * Eris 95.6 AU, Kuiper belt *

Gonggong Gonggong () is a Chinese water god who is depicted in Chinese mythology and folktales as having a copper human head with an iron forehead, red hair, and the body of a serpent, or sometimes the head and torso are human, with the tail of a serpen ...

Scattered disc object, 34 to 101 AU *

Quaoar Quaoar (minor-planet designation: 50000 Quaoar) is a ringed dwarf planet in the Kuiper Belt, a ring of many icy planetesimals beyond Neptune. It has an elongated ellipsoidal shape with an average diameter of , about half the size of the dwarf ...

Kuiper belt object, 41.9 to 45.4 AU * Sedna 76 to 506 AU

References

External links

Expected Science Return of Spatially-Extended In-Situ Exploration at Small Solar System Bodies
{{Portal bar, Solar System, Astronomy, Earth sciences, Stars, Spaceflight Solar System Planetary science Space science

Formation

Solar System belts

Planets

See also

References

External links