The Pasiphae group is a group of retrograde irregular satellites of Jupiter that follow similar orbits to Pasiphae and are thought to have a common origin.
Their semi-major axes (distances from Jupiter) range between 22.6 and 24.3 million km (similar range as the Carme group), their inclinations between 141.5° and 157.3°, and their eccentricities between 0.22 and 0.44.
The members of the Pasiphae group are: [1]
Name | Diameter (km) [2] | Period (days) [3] [note 1] | Notes |
---|---|---|---|
Pasiphae | 58 | –743.61 | largest member and group prototype |
Sinope | 38 | –758.85 | red colour |
Callirrhoe | 7 | –758.87 | reddish colour |
Megaclite | 6 | –752.86 | reddish colour |
Autonoe | 4 | –761.00 | |
Eurydome | 3 | –717.31 | |
Sponde | 2 | –748.29 | |
Hegemone | 3 | –739.81 | |
Aoede | 4 | –761.42 | |
Cyllene | 2 | –751.97 | |
Kore | 2 | –776.76 | |
S/2011 J 2 | 1 | –718.32 | |
Philophrosyne | 2 | –702.54 | |
S/2017 J 1 | 2 | –756.41 | |
S/2017 J 6 | 2 | –733.99 | |
S/2003 J 4 | 2 | –718.10 | |
S/2003 J 23 | 2 | –760.00 | |
S/2016 J 4 | 1 | –727.01 |
The International Astronomical Union (IAU) reserves names ending in -e for all retrograde moons.
The Pasiphae group is believed to have been formed when Jupiter captured an asteroid which subsequently broke up after a collision. The original asteroid was not disturbed heavily: the original body is calculated to have been 60 km in diameter, about the same size as Pasiphae; Pasiphae retains 99% of the original body's mass. However, if Sinope belongs to the group, the ratio is much smaller, 87%. [4]
Unlike the Carme and Ananke groups, the theory of a single impact origin for the Pasiphae group is not accepted by all studies. This is because the Pasiphae group, while similar in semi-major axis, is more widely dispersed in inclination. [note 2] Alternatively, Sinope might be not a part of the remnants of the same collision and captured independently instead. [6] The differences of colour between the objects (grey for Pasiphae, light red for Callirrhoe and Megaclite) also suggest that the group could have a more complex origin than a single collision. [6]
Carme is a retrograde irregular satellite of Jupiter. It was discovered by Seth Barnes Nicholson at Mount Wilson Observatory in California in July 1938. It is named after the mythological Carme, mother by Zeus of Britomartis, a Cretan goddess.
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Pasiphae, formerly spelled Pasiphaë, is a retrograde irregular satellite of Jupiter. It was discovered in 1908 by Philibert Jacques Melotte and later named after the mythological Pasiphaë, wife of Minos and mother of the Minotaur from Greek legend.
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In astronomy, an irregular moon, irregular satellite, or irregular natural satellite is a natural satellite following a distant, inclined, and often highly elliptical and retrograde orbit. They have been captured by their parent planet, unlike regular satellites, which formed in orbit around them. Irregular moons have a stable orbit, unlike temporary satellites which often have similarly irregular orbits but will eventually depart. The term does not refer to shape; Triton, for example, is a round moon but is considered irregular due to its orbit and origins.