Harpalyke (moon)

Harpalyke /hɑːrˈpæləkiː/, also known as Jupiter XXII, is a little retrograde irregular satellite of Jupiter.

Harpalyke

Harpalyke imaged by the Canada-France-Hawaii Telescope in December 2001
Discovery[1]
Discovered by	Scott S. Sheppard David C. Jewitt Yanga R. Fernandez Eugene A. Magnier
Discovery site	Mauna Kea Observatory
Discovery date	23 November 2000
Designations
Designation	Jupiter XXII
Pronunciation	/hɑːrˈpæləkiː/[2]
Named after	Ἁρπαλύκη Harpălykē
Alternative names	S/2000 J 5
Adjectives	Harpalykean /hɑːrpələˈkiːən/
Orbital characteristics[3]
Epoch 17 December 2020 (JD 2459200.5)
Observation arc	17.39 yr (6,350 days)
Semi-major axis	0.1422492 AU (21,280,180 km)
Eccentricity	0.1602677
Orbital period (sidereal)	–634.19 d
Mean anomaly	321.08380°
Mean motion	0° 34m 3.555s / day
Inclination	148.29788° (to ecliptic)
Longitude of ascending node	92.54746°
Argument of perihelion	193.28018°
Satellite of	Jupiter
Group	Ananke group
Physical characteristics[4]
Mean diameter	4 km
Albedo	0.04 (assumed)
Spectral type	C[5]
Apparent magnitude	22.2[6]
Absolute magnitude (H)	15.9[3]

Discovery and Naming

It was discovered by a team of astronomers from the University of Hawaiʻi led by Scott S. Sheppard in 2000, and given the temporary designation S/2000 J 5.^[7][1]

In August 2003, the moon was named^[8] after Harpalyce, the incestuous daughter of Clymenus, who in some accounts was also a lover of Zeus (Jupiter).

Orbit

The satellite orbits Jupiter at an average distance of 21,280,180 km in 634.19 days, at an inclination of 148° to the ecliptic with an eccentricity of 0.160. Its orbit is continuously changing due to solar and planetary perturbations.

It belongs to the Ananke group, made up a tightly of irregular retrograde moons orbiting Jupiter at a distance ranging between 19–22 million km, inclinations between 144 and 156°, and eccentricities between 0.10 and 0.30.

Physical characteristics

It is about 4 kilometres in diameter (assumed albedo 4%) ^[9] and appears grey (color index R-V=0.43), similar to C-type asteroids.^[5]

Origin

Iocaste probably did not form near Jupiter but was captured by Jupiter later.Like the other members of the Ananke group, which have similar orbits, Iocaste is probably the remnant of a broken, captured heliocentric asteroid.^[10][11]