Thyone (moon)

Thyone /θaɪˈoʊniː/, also known as Jupiter XXIX, is a retrograde irregular satellite of Jupiter. It was discovered by a team of astronomers from the University of Hawaii led by Scott S. Sheppard in 2001, and given the temporary designation S/2001 J 2.^[7][1]

Thyone

Discovery images of Thyone by the Canada-France-Hawaii Telescope in December 2001
Discovery[1]
Discovered by	Scott S. Sheppard et al.
Discovery site	Mauna Kea Obs.
Discovery date	11 December 2001
Designations
Designation	Jupiter XXIX
Pronunciation	/θaɪˈoʊniː/[2]
Named after	Θυώνη Thyōnē
Alternative names	S/2001 J 2
Adjectives	Thyonean /ˌθaɪəˈniːən/[3]
Orbital characteristics[4]
Semi-major axis	20940000 km
Eccentricity	0.229
Orbital period (sidereal)	−603.58 days[5]
Mean anomaly	26.6°
Inclination	148.5°
Longitude of ascending node	243.0°
Argument of perihelion	89.1°
Satellite of	Jupiter
Group	Ananke group
Physical characteristics
Mean diameter	4 km
Spectral type	B–V = 0.71 ± 0.06, V–R = 0.45 ± 0.04[6]
Apparent magnitude	22.3

Thyone is about 4 kilometres in diameter, and orbits Jupiter at an average distance of 21,605,000 kilometres in 603.58 days, at an inclination of 147.28° to the ecliptic (146.93° to Jupiter's equator) with an eccentricity of 0.2526. Its average orbital speed is 2.43 km/s.

It was named in August 2003 after Thyone, better known as Semele, mother of Dionysus in Greek mythology.^[8]

Thyone belongs to the Ananke group, retrograde irregular moons which orbit Jupiter between 19.3 and 22.7 million kilometres, at inclinations of roughly 150°.

Thyone imaged by the CFHT on 10 December 2001, one day before its discovery