Thyone (moon)

Thyone

Discovery images of Thyone by the Canada-France-Hawaii Telescope in December 2001
Discovery
Discovered by	Scott S. Sheppard et al.
Discovery site	Mauna Kea Obs.
Discovery date	11 December 2001
Designations
Designation	Jupiter XXIX
Pronunciation	/θaɪˈoʊniː/
Named after	Θυώνη Thyōnē
Alternative names	S/2001 J 2
Adjectives	Thyonean /ˌθaɪəˈniːən/
Orbital characteristics
Semi-major axis	20940000 km
Eccentricity	0.229
Orbital period (sidereal)	−603.58 days
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
Apparent magnitude	22.3

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.

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.

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