A satellite is a celestial body orbiting in a certain trajectory ( orbit ) around another object in outer space under the influence of gravity . Distinguish between artificial and natural satellites.
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Definition
For the first time the concept of "satellite" was used by Johannes Kepler in the work of Narratio de Iovis Satellitibus , published in 1611 in Frankfurt [1] . A synonym for this term in everyday life is the word "moon".
Among astronomers there is an opinion that it is necessary to consider a satellite as an object rotating around a central body ( stars [2] , a planet , a dwarf planet or an asteroid ) so that the barycenter of the system consisting of this object and the central body is inside the central body. If the barycenter is outside the central body, the object should not be considered a satellite, but should be considered a component of a system consisting of two or more planets (dwarf planets, asteroids). However, the International Astronomical Union has not yet given a strict definition of the satellite, stating that this will be done later [3] . In particular, the IAU continues to officially consider Charon a satellite of Pluto .
In addition to the above, there are other possible ways of formal definition of the concept of "satellite" [4] .
Naming Natural Satellites
When a natural satellite is discovered, it is assigned a designation and number, and later also its own name. According to tradition, the discoverer of the satellite has the right to choose this name. The names proposed by him must correspond to the names of previously discovered satellites of the celestial body around which he is turning. History knows two exceptions to the tradition of choosing the name as the discoverer: the names of the first seven satellites of Saturn and also the four satellites of Uranus were assigned by John Herschel , the son of the astronomer William Herschel , and the satellites of Jupiter, discovered from 1892 to 1974 and remaining unnamed discoverers, were given names by the International astronomical union in 1975 [1] .
Since 1919, the International Astronomical Union (IAU) has been regulating the assignment of satellite names, and since 1973, the Working Group on the Planetary System Nomenclature ( WGPSN [5] ) created by it.
The following naming procedure applies. The discovery of a new satellite is reported to the Central Bureau of Astronomical Telegrams in Cambridge , which assigns it a temporary designation (for example, type S / 2017 S1 for the satellite of Saturn) and sends out information about the discovery in a circular. A proper name is assigned after the elements of the satellite’s orbit are set with sufficient accuracy. The naming proposed by the discoverer is submitted for discussion by WGPSN, and following its results it is submitted for approval to the Executive Committee and the General Assembly of the IAC, which finally approves it [5] .
Most of the satellite names are borrowed from Greek and Roman mythology ; the exceptions are the satellites of Uranus , the names of which are borrowed from the plays of Shakespeare and the poem “Theft of a Curl” by Alexander Pope , as well as the irregular satellites of Saturn , for which the names (mainly giants) from Inuit , Gallic and Scandinavian mythology are used [5] .
Satellites at satellites
Satellites can also have their own satellites, but in most cases the tidal forces of the main body would make such a system unstable. There were speculations about the presence of satellites on the Moon , Rhea, and Iapetus , but satellites of natural origin were not detected on the satellites.
See also
- Artificial Earth Satellite
- Satellites of the planets
- List of geostationary satellites
Notes
- ↑ 1 2 Blunck J. Solar System Moons : Discovery and Mythology - Berlin , Heidelberg : Springer Science + Business Media , 2010 .-- P. VII. - 142 p. - ISBN 978-3-540-68852-5 - doi: 10.1007 / 978-3-540-68853-2
- ↑ MSFC, Jennifer Wall:. What is a satellite? (Eng.) , NASA (May 15, 2015). Date of treatment March 8, 2017.
- ↑ Pluto and the Developing Landscape of Our Solar System
- ↑ Moon - satellite or planet?
- ↑ 1 2 3 Blunck J. Solar System Moons : Discovery and Mythology - Berlin , Heidelberg : Springer Science + Business Media , 2010 .-- P. VIII. - 142 p. - ISBN 978-3-540-68852-5 - doi: 10.1007 / 978-3-540-68853-2
Links
- Natural Satellite Physical Parameters (JPL-NASA, with refs - last updated July 2006 )
- Moons of the Solar System (The Planetary Society, as of March 2009 )
- JPL's Solar System Dynamics page
- Planetary Names: Planet and Satellite Names and Discoverers
- "Upper size limit for moons explained" Kelly Young. Nature (vol 441, p. 834) June 14, 2006