Callirrhoe (moon)
Encyclopedia
Callirrhoe also known as (17), is one of Jupiter
's outermost named natural satellite
s. It is an irregular moon that orbits in a retrograde
direction. Callirrhoe was imaged by Spacewatch
at Kitt Peak National Observatory
from October 6 through November 4, 1999, and originally designated as asteroid
. It was discovered to be in orbit around Jupiter by Tim Spahr
on July 18, 2000, and then given the designation . It was the 17th confirmed moon of Jupiter.
Callirrhoe has an apparent magnitude
of 20.7, making it even fainter than dwarf planet
Eris
at magnitude 18.7. Jupiter is about 2.5 million times brighter than Callirrhoe.
Callirrhoe is about 8.6 kilometers in diameter, and orbits Jupiter at an average distance of 24.1 million kilometers in 758 days, at an inclination
of 141° to the ecliptic
(140° to Jupiter's equator) with an eccentricity of 0.28. This object was probably captured long ago from a heliocentric orbit and the Sun's gravitational influence makes this orbit highly erratic.
It was named in October 2002 after Callirrhoe
, daughter of the river god Achelous
, one of Zeus
' (Jupiter's) many conquests.
It belongs to the Pasiphaë group
, irregular retrograde moons orbiting Jupiter at distances ranging between 22.8 and 24.1 million kilometers, and with inclination
s ranging between 144.5° and 158.3°.
As a navigation exercise, the New Horizons
spacecraft imaged it on January 10, 2007.
Jupiter
Jupiter is the fifth planet from the Sun and the largest planet within the Solar System. It is a gas giant with mass one-thousandth that of the Sun but is two and a half times the mass of all the other planets in our Solar System combined. Jupiter is classified as a gas giant along with Saturn,...
's outermost named natural satellite
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....
s. It is an irregular moon that orbits in a retrograde
Retrograde and direct motion
Apparent retrograde motion is the motion of a planetary body in a direction opposite to that of other bodies within its system as observed from a particular vantage point...
direction. Callirrhoe was imaged by Spacewatch
Spacewatch
Spacewatch is a project at the University of Arizona led by Robert S. McMillan that specializes in the study of minor planets, including various types of asteroids and comets...
at Kitt Peak National Observatory
Kitt Peak National Observatory
The Kitt Peak National Observatory is a United States astronomical observatory located on 2,096 m Kitt Peak of the Quinlan Mountains in the Arizona-Sonoran Desert on the Tohono O'odham Nation, southwest of Tucson...
from October 6 through November 4, 1999, and originally designated as asteroid
Asteroid
Asteroids are a class of small Solar System bodies in orbit around the Sun. They have also been called planetoids, especially the larger ones...
. It was discovered to be in orbit around Jupiter by Tim Spahr
Timothy B. Spahr
Timothy B. Spahr is an American astronomer.He works at the Harvard-Smithsonian Center for Astrophysics as director of the Minor Planet Center, has discovered numerous asteroids and is credited as a co-discoverer of one satellite of Jupiter and one of Saturn .He also discovered two periodic comets...
on July 18, 2000, and then given the designation . It was the 17th confirmed moon of Jupiter.
Callirrhoe has an apparent magnitude
Apparent magnitude
The apparent magnitude of a celestial body is a measure of its brightness as seen by an observer on Earth, adjusted to the value it would have in the absence of the atmosphere...
of 20.7, making it even fainter than dwarf planet
Dwarf planet
A dwarf planet, as defined by the International Astronomical Union , is a celestial body orbiting the Sun that is massive enough to be spherical as a result of its own gravity but has not cleared its neighboring region of planetesimals and is not a satellite...
Eris
Eris (dwarf planet)
Eris, formal designation 136199 Eris, is the most massive known dwarf planet in the Solar System and the ninth most massive body known to orbit the Sun directly...
at magnitude 18.7. Jupiter is about 2.5 million times brighter than Callirrhoe.
Callirrhoe is about 8.6 kilometers in diameter, and orbits Jupiter at an average distance of 24.1 million kilometers in 758 days, at an inclination
Inclination
Inclination in general is the angle between a reference plane and another plane or axis of direction.-Orbits:The inclination is one of the six orbital parameters describing the shape and orientation of a celestial orbit...
of 141° to the ecliptic
Ecliptic
The ecliptic is the plane of the earth's orbit around the sun. In more accurate terms, it is the intersection of the celestial sphere with the ecliptic plane, which is the geometric plane containing the mean orbit of the Earth around the Sun...
(140° to Jupiter's equator) with an eccentricity of 0.28. This object was probably captured long ago from a heliocentric orbit and the Sun's gravitational influence makes this orbit highly erratic.
It was named in October 2002 after Callirrhoe
Callirrhoe (naiad)
In Greek mythology, Callirrhoe was a naiad. She was the daughter of Oceanus and Tethys. She had three husbands, Chrysaor, Neilus and Poseidon. She was one of the three ancestors of the Tyrians, along with Abarbarea and Drosera...
, daughter of the river god Achelous
Achelous
In Greek mythology, Achelous was the patron deity of the "silver-swirling" Achelous River, which is the largest river of Greece, and thus the chief of all river deities, every river having its own river spirit. His name is pre-Greek, its meaning unknown...
, one of Zeus
Zeus
In the ancient Greek religion, Zeus was the "Father of Gods and men" who ruled the Olympians of Mount Olympus as a father ruled the family. He was the god of sky and thunder in Greek mythology. His Roman counterpart is Jupiter and his Etruscan counterpart is Tinia.Zeus was the child of Cronus...
' (Jupiter's) many conquests.
It belongs to the Pasiphaë group
Pasiphaë group
The Pasiphaë group is a group of retrograde irregular satellites of Jupiter that follow similar orbits to Pasiphaë and are thought to have a common origin....
, irregular retrograde moons orbiting Jupiter at distances ranging between 22.8 and 24.1 million kilometers, and with inclination
Inclination
Inclination in general is the angle between a reference plane and another plane or axis of direction.-Orbits:The inclination is one of the six orbital parameters describing the shape and orientation of a celestial orbit...
s ranging between 144.5° and 158.3°.
As a navigation exercise, the New Horizons
New Horizons
New Horizons is a NASA robotic spacecraft mission currently en route to the dwarf planet Pluto. It is expected to be the first spacecraft to fly by and study Pluto and its moons, Charon, Nix, Hydra and S/2011 P 1. Its estimated arrival date at the Pluto-Charon system is July 14th, 2015...
spacecraft imaged it on January 10, 2007.