Eirene , also Jupiter LVII and originally known as , 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 2003IAUC 8087: Satellites of Jupiter 2003 March 4 (discovery)MPEC 2003-E11: S/2003 J 1, 2003 J 2, 2003 J 3, 2003 J 4, 2003 J 5, 2003 J 6, 2003 J 7 2003 March 4 (discovery and ephemeris) but was then  lost.
It was recovered in 2017 and given its permanent designation that year.
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).
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