Overview

Kallichore, also catalogued as Jupiter XLIV and initially designated S/2003 J 11, is one of Jupiter's many small irregular satellites. It is a faint, non-spherical body roughly 2 kilometres across that follows a distant, retrograde orbit around the planet. Because of its size and brightness, Kallichore is observable only with large telescopes and sensitive detectors; it is best known as a member of a dynamical family of moons that share similar orbits and likely a common origin.

Discovery and name

The moon was discovered in 2003 by a team from the University of Hawaii led by Scott S. Sheppard and colleagues using ground-based survey techniques. Upon discovery it received the provisional designation S/2003 J 11 and was later given the permanent name Kallichore in March 2005. The name derives from a figure in Greek myth—described in modern sources as a nymph associated with the deities linked to Zeus/Jupiter—following the convention of naming Jovian satellites after characters related to Zeus.

Orbit and physical characteristics

Kallichore orbits Jupiter at an average distance of about 23,112,000 kilometres and completes one orbit in roughly 717.8 days. Its motion is retrograde, meaning it moves around Jupiter in the opposite direction to the planet's rotation. The orbit is inclined about 165 degrees to the ecliptic plane (about 164 degrees relative to Jupiter's equator), as recorded in published orbital elements; see inclination data. Kallichore's orbit is moderately eccentric, with an eccentricity near 0.2042 according to available measurements; see eccentricity information. Its small size implies a low surface gravity and a likely irregular shape rather than a spherical form.

Carme group and origin

Kallichore is catalogued as a member of the Carme group, a population of retrograde irregular satellites that orbit Jupiter at distances between about 23 and 24 million kilometres and share similar inclinations near 165 degrees. The group's namesake is the moon Carme; members of the group are thought to be fragments of a parent body that was captured by Jupiter and later disrupted by a collision. Many members of this family have comparable colours and spectral characteristics, supporting a common origin hypothesis. For a general overview of the group see Carme group and for notes on physical shape see irregular, non-spherical satellites.

Scientific significance and observation

Although Kallichore itself is small and contributes little to Jupiter's overall mass, studying such satellites helps astronomers reconstruct the capture and collisional history of the giant planet's satellite system. Observations of orbital dynamics, colour indices and light curves can indicate composition, rotational properties and whether a moon is a fragment from a larger progenitor. Continued monitoring refines orbital parameters and can reveal subtle perturbations from other moons or solar tides.

Notable facts and distinctions

  • Designation: S/2003 J 11; permanent name Kallichore (assigned 2005).
  • Size: approximately 2 kilometres in diameter; irregular shape assumed.
  • Orbit: retrograde, ~23.11 million km from Jupiter, orbital period ~717.8 days, inclination ~165° to the ecliptic.
  • Group: member of the Carme group—likely a collisional fragment from a captured body.

Kallichore exemplifies the class of small irregular Jovian moons whose collective properties illuminate processes of capture, fragmentation and long-term orbital evolution in the outer regions of giant-planet systems.