Pasiphae , formerly spelled Pasiphaë, is a retrograde

irregular satellite In astronomy, an irregular moon, irregular satellite or irregular natural satellite is a natural satellite following a distant, inclined, and often eccentric and retrograde orbit. They have been captured by their parent planet, unlike regular s ...

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 mass more than two and a half times that of all the other planets in the Solar System combined, but ...

. It was discovered in 1908 by

Philibert Jacques Melotte Philibert Jacques Melotte (29 January 1880 – 30 March 1961) was a British astronomer whose parents emigrated from Belgium. In 1908 he discovered a moon of Jupiter, today known as Pasiphaë. It was simply designated "Jupiter VIII" and was ...

and later named after the mythological

Pasiphaë In ancient Greek religion and Greek mythology, Pasiphaë (; grc-gre, Πασιφάη, Pasipháē, lit=wide-shining derived from πάσι (archaic dative plural) "for all" and φάος/φῶς ''phaos/phos'' "light") was a queen of Crete, and wa ...

, wife of

Minos In Greek mythology, Minos (; grc-gre, Μίνως, ) was a King of Crete, son of Zeus and Europa. Every nine years, he made King Aegeus pick seven young boys and seven young girls to be sent to Daedalus's creation, the labyrinth, to be eaten ...

and mother of the

Minotaur In Greek mythology, the Minotaur ( , ;. grc, ; in Latin as ''Minotaurus'' ) is a mythical creature portrayed during classical antiquity with the head and tail of a bull and the body of a man or, as described by Roman poet Ovid, a being "pa ...

from Greek legend. The moon was first spotted on a plate taken at the Royal Greenwich Observatory on the night of 28 February 1908. Inspection of previous plates found it as far back as January 27. It received the

provisional designation Provisional designation in astronomy is the naming convention applied to astronomical objects immediately following their discovery. The provisional designation is usually superseded by a permanent designation once a reliable orbit has been calcu ...

, as it was not clear whether it was an asteroid or a moon of Jupiter. The recognition of the latter case came by April 10. Pasiphae did not receive its present name until 1975; before then, it was simply known as . It was sometimes called "Poseidon" between 1955 and 1975.

Orbit

Pasiphae orbits Jupiter on a high eccentricity and high inclination retrograde orbit. It gives its name to the

Pasiphae group 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 22.8 and 24.1 million km (th ...

, irregular retrograde moons orbiting Jupiter at distances ranging between 22.8 and 24.1 million km, and with

inclination Orbital inclination measures the tilt of an object's orbit around a celestial body. It is expressed as the angle between a Plane of reference, reference plane and the orbital plane or Axis of rotation, axis of direction of the orbiting object ...

s ranging between 144.5° and 158.3°. Sheppard, S. S.; Jewitt, D. C.; and Porco, C. C.
''Jupiter's Outer Satellites and Trojans''
, in ''Jupiter: The Planet, Satellites and Magnetosphere,'' edited by Fran Bagenal, Timothy E. Dowling, and William B. McKinnon, Cambridge Planetary Science, Vol. 1, Cambridge, UK: Cambridge University Press, , 2004, pp. 263-280 The orbital elements are as of January 2000. They are continuously changing due to solar and planetary perturbations. The diagram illustrates its orbit in relation to other retrograde irregular satellites of Jupiter. The eccentricity of selected orbits is represented by the yellow segments (extending from the

pericentre An apsis (; ) is the farthest or nearest point in the orbit of a planetary body about its primary (astronomy), primary body. For example, the apsides of the Earth are called the aphelion and perihelion. General description There are two ...

to the apocentre). The outermost regular satellite

Callisto Callisto most commonly refers to: *Callisto (mythology), a nymph *Callisto (moon), a moon of Jupiter Callisto may also refer to: Art and entertainment *''Callisto series'', a sequence of novels by Lin Carter *''Callisto'', a novel by Torsten Kro ...

is located for reference. Pasiphae is also known to be in a

secular resonance A secular resonance is a type of orbital resonance between two bodies with synchronized precessional frequencies. In celestial mechanics, secular refers to the long-term motion of a system, and resonance is periods or frequencies being a simple n ...

with Jupiter (tying the longitude of its perijove with the longitude of perihelion of Jupiter).

Physical characteristics

With diameter estimated at 60 km Pasiphae is the largest retrograde and third largest irregular satellite after Himalia and Elara. Spectroscopical measurements in

infrared Infrared (IR), sometimes called infrared light, is electromagnetic radiation (EMR) with wavelengths longer than those of visible light. It is therefore invisible to the human eye. IR is generally understood to encompass wavelengths from around ...

indicate that Pasiphae is a spectrally featureless object, consistent with the suspected

asteroid An asteroid is a minor planet of the inner Solar System. Sizes and shapes of asteroids vary significantly, ranging from 1-meter rocks to a dwarf planet almost 1000 km in diameter; they are rocky, metallic or icy bodies with no atmosphere. ...

al origin of the object. Pasiphae is believed to be a fragment from a captured

along with other Pasiphae group satellites.Sheppard, S. S.; and Jewitt, D. C.
''An Abundant Population of Small Irregular Satellites Around Jupiter''
, Nature, Vol. 423 (May 2003), pp. 261-263 In the visual spectrum the satellite appears grey ( colour indices B-V=0.74, R-V=0.38) similar to

C-type asteroid C-type (carbonaceous) asteroids are the most common variety, forming around 75% of known asteroids. They are volatile-rich and distinguished by a very low albedo because their composition includes a large amount of carbon, in addition to rocks ...

s. Grav, T.; Holman, M. J.; Gladman, B. J.; and Aksnes, K.
''Photometric Survey of the Irregular Satellites''
Icarus, Vol. 166 (2003), pp. 33-45

References

External links

Pasiphae Profile
b
NASA's Solar System Exploration

{{DEFAULTSORT:Pasiphae (Moon) Moons of Jupiter Irregular satellites 19080127 Pasiphae group Moons with a retrograde orbit

Orbit

Physical characteristics

See also

References

External links