Eirene (moon)

Eirene /aɪˈriːniː/, also Jupiter LVII and originally known as S/2003 J 5, is a retrograde irregular satellite of Jupiter. It was discovered by a team of astronomers from the University of Hawaiʻi led by Scott S. Sheppard in 2003^[3][4] but was then lost.^[5][6][7][8] It was recovered in 2017 and given its permanent designation that year.^[9]

Eirene

Discovery
Discovered by	Scott Sheppard et al.
Discovery date	2003
Designations
Designation	Jupiter LVII
Pronunciation	/aɪˈriːniː/
Named after	Εἰρήνη Eirēnē
Alternative names	S/2003 J 5
Adjectives	Eirenean /aɪrɪˈniːən/
Orbital characteristics[1]
Semi-major axis	23731770 km
Eccentricity	0.2413
Orbital period (sidereal)	−743.88 days[2] (2.038 years)
Inclination	162.713° (to the ecliptic)
Satellite of	Jupiter
Group	Carme group
Physical characteristics
Mean diameter	4 km
Apparent magnitude	22.5
Absolute magnitude (H)	15.8[2]

Characteristics

Eirene is about 4 kilometres in diameter, and orbits Jupiter at an average distance of 23,974,000 km in 743.88 days, at an inclination of 166° to the ecliptic (167° to Jupiter's equator), in a retrograde direction and with an eccentricity of 0.307.

It belongs to the Carme group, made up of irregular retrograde moons orbiting Jupiter at a distance ranging between 23 and 24 Gm and at an inclination of about 165°.

Name

The moon was named in 2019 after Eirene (Εἰρήνη), the daughter of Zeus and Themis and the goddess of peace in Greek mythology; the name originated from a naming contest held on Twitter with sixteen tweets suggesting the name, most significantly by users Quadrupoltensor (@Quadrupoltensor) who first suggested the name and PaulR (@PJRYYC).^[10][11][12]