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Pallene (moon)
Encyclopedia
Pallene is a very small natural satellite
of Saturn
. It is one of three small moons known as the Alkyonides that lie between the orbits of the larger Mimas
and Enceladus
. It is also designated as .
Pallene was discovered by the Cassini Imaging Team in 2004, during the Cassini–Huygens mission. It was given the temporary designation . In 2005, the name Pallene was provisionally approved by the IAU Division III Working Group for Planetary System Nomenclature, and was ratified at the IAU General Assembly in 2006. The name refers to Pallene, one of the Alkyonides
, the seven beautiful daughters of the giant
Alkyoneus.
After the discovery in 2004, it was realized that Pallene had been first photographed on August 23, 1981, by the space probe . It had appeared in a single photograph and had been provisionally named and estimated to orbit 200,000 km from Saturn. Since it had not been visible in other images, it had not been prossible to compute its orbit at the time, but recent comparisons have shown it to match Pallene's orbit.
. The perturbations cause Pallene's osculating orbit
al elements to vary with an amplitude of about 4 km in semi-major axis, and 0.02° in longitude (corresponding to about 75 km). Eccentricity also changes on various timescales between 0.002 and 0.006, and inclination between about 0.178° and 0.184°.
Natural satellite
A natural satellite or moon is a celestial body that orbits a planet or smaller body, which is called its primary. The two terms are used synonymously for non-artificial satellites of planets, of dwarf planets, and of minor planets....
of Saturn
Saturn
Saturn is the sixth planet from the Sun and the second largest planet in the Solar System, after Jupiter. Saturn is named after the Roman god Saturn, equated to the Greek Cronus , the Babylonian Ninurta and the Hindu Shani. Saturn's astronomical symbol represents the Roman god's sickle.Saturn,...
. It is one of three small moons known as the Alkyonides that lie between the orbits of the larger Mimas
Mimas (moon)
Mimas is a moon of Saturn which was discovered in 1789 by William Herschel. It is named after Mimas, a son of Gaia in Greek mythology, and is also designated Saturn I....
and Enceladus
Enceladus (moon)
Enceladus is the sixth-largest of the moons of Saturn. It was discovered in 1789 by William Herschel. Until the two Voyager spacecraft passed near it in the early 1980s very little was known about this small moon besides the identification of water ice on its surface...
. It is also designated as .
Discovery
Alkyonides
The Alkyonides were, in Greek mythology, the seven daughters of Alcyoneus. When their father was slain by Heracles, they threw themselves into the sea, and were transformed into halcyons by Amphitrite...
, the seven beautiful daughters of the giant
Giant (mythology)
The mythology and legends of many different cultures include monsters of human appearance but prodigious size and strength. "Giant" is the English word commonly used for such beings, derived from one of the most famed examples: the gigantes of Greek mythology.In various Indo-European mythologies,...
Alkyoneus.
After the discovery in 2004, it was realized that Pallene had been first photographed on August 23, 1981, by the space probe . It had appeared in a single photograph and had been provisionally named and estimated to orbit 200,000 km from Saturn. Since it had not been visible in other images, it had not been prossible to compute its orbit at the time, but recent comparisons have shown it to match Pallene's orbit.
Orbital characteristics
Pallene is visibly affected by a perturbing mean longitude resonance with the much larger Enceladus, although this effect is not as large as the Mimas perturbations on MethoneMethone (moon)
Methone is a very small natural satellite of Saturn lying between the orbits of Mimas and Enceladus.It was first seen by the Cassini Imaging Team and given the temporary designation '. Methone is also named '....
. The perturbations cause Pallene's osculating orbit
Osculating orbit
In astronomy, and in particular in astrodynamics, the osculating orbit of an object in space is the gravitational Kepler orbit In astronomy, and in particular in astrodynamics, the osculating orbit of an object in space (at a given moment of time) is the gravitational Kepler orbit In astronomy,...
al elements to vary with an amplitude of about 4 km in semi-major axis, and 0.02° in longitude (corresponding to about 75 km). Eccentricity also changes on various timescales between 0.002 and 0.006, and inclination between about 0.178° and 0.184°.