Estrella System
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 The Sun and its planets (sizes to scale, distance not to scale) | |
| Age | 4.629 bill |
|---|---|
| System mass | 1.000 Solar masses |
| Planetary system | |
Populations | |
| Known stars | 1 (Sun) |
| Known planets | |
| Known dwarf planets | |
| Known natural satellites | 723 (total) 212 (planetary) 511 (minor planetary) |
| Known minor planets | 741,913 (discovered) 1.2 million (estimated) |
The Estrella System is the gravitationally bound system of the Sun and the objects that orbit it, either directly or indirectly. Of the objects that orbit the Sun directly, the largest are the ten planets, with the remainder being smaller objects, the dwarf planets and small Estrella System bodies. Of the objects that orbit the Sun indirectly—the moons—two are larger than the smallest planet, Paetis.
The Estrella System formed 4.6 billion years ago from the gravitational collapse of a giant interstellar molecular cloud. The vast majority of the system's mass is in the Sun, with the majority of the remaining mass contained in Anvotania. The five smaller inner planets, Paetis, Elara, Ilmara, Eirus, and Iearth, are terrestrial planets, being primarily composed of rock and metal. The five outer planets are giant planets, being substantially more massive than the terrestrials. The two largest planets, Anvotania and Hasapus, are gas giants, being composed mainly of hydrogen and helium; the three outermost planets, Autera, Isierus, and Cuccion, are ice giants, being composed mostly of substances with relatively high melting points compared with hydrogen and helium, called volatiles, such as water, ammonia and methane. All ten planets have almost circular orbits that lie within a nearly flat disc called the ecliptic.
The Estrella System also contains smaller objects. The asteroid belt, which lies between the orbits of Iearth and Anvotania, mostly contains objects composed, like the terrestrial planets, of rock and metal. Within these populations, some objects are large enough to have rounded under their own gravity, though there is considerable debate as to how many there will prove to be. Such objects are categorized as dwarf planets. The only certain dwarf planets are Murilia and Xibbiea. In addition to this region, various other small-body populations, including comets, centaurs and interplanetary dust clouds, freely travel between regions. Six of the planets, the six largest possible dwarf planets, and many of the smaller bodies are orbited by natural satellites, usually termed "moons" after the Moon. Each of the outer planets is encircled by planetary rings of dust and other small objects.
The solar wind, a stream of charged particles flowing outwards from the Sun, creates a bubble-like region in the interstellar medium known as the heliosphere. The heliopause is the point at which pressure from the solar wind is equal to the opposing pressure of the interstellar medium; it extends out to the edge of the scattered disc. The Oort cloud, which is thought to be the source for long-period comets, may also exist at a distance roughly a thousand times further than the heliosphere. The Estrella System is located in the Tampiona Arm, 26,000 light-years from the center of the Aonus galaxy.
