Helike (moon)

Helike /ˈhɛləkiː/, also known as Jupiter XLV, is a moon of Jupiter. It was discovered by a team of astronomers from the University of Hawaii led by Scott S. Sheppard in 2003, and given the temporary designation S/2003 J 6.^[5][6][7]

Helike

Images of Helike by the Canada-France-Hawaii Telescope in February 2003
Discovery
Discovered by	Scott S. Sheppard et al.
Discovery date	2003
Designations
Designation	Jupiter XLV
Pronunciation	/ˈhɛləkiː/[1][2]
Named after	Ἑλίκη Helicē
Alternative names	S/2003 J 6
Adjectives	Helikean /hɛləˈkiːən/[3]
Orbital characteristics[4]
Semi-major axis	21263000 km
Eccentricity	0.156
Orbital period (sidereal)	−634.8 days
Mean anomaly	36.2°
Inclination	154.8°
Longitude of ascending node	100.3°
Argument of perihelion	314.7°
Satellite of	Jupiter
Group	Ananke group
Physical characteristics
Mean diameter	4 km
Apparent magnitude	22.6

Helike is about 4 kilometres in diameter, and orbits Jupiter at an average distance of 20.54 million kilometres in 601.402 days, at an inclination of 155° to the ecliptic (156° to Jupiter's equator), in a retrograde direction and with an eccentricity of 0.1375. Its average orbital speed is 2.48 km/s.

It was named in March 2005 after Helike, one of the nymphs that nurtured Zeus (Jupiter) in his infancy on Crete.^[8]

Helike belongs to the Ananke group.