Isonoe (moon)
A small retrograde irregular moon of Jupiter.
Isonoe, also called Jupiter XXVI, is a small moon of Jupiter that orbits the planet backwards and on a tilted path. It belongs to the Carme group, a cluster of irregular moons that share similar orbits and are thought to be fragments of a single captured asteroid that later broke apart.
Discovered in 2000 by a University of Hawaiʻi team led by Scott S. Sheppard, it was first labeled S/2000 J 6. In October 2002, it was named after Isonoe, one of the Danaïdes from Greek mythology and a lover of Zeus (Jupiter).
The moon orbits Jupiter at an average distance of about 23,322,670 km, completing one orbit in roughly 691.62 days. Its orbit is tilted about 165° to the ecliptic, moves in a retrograde direction, and has an eccentricity of 0.226. The Carme group’s orbits range from 22.7 to 23.5 million km from Jupiter, with inclinations near 165° and eccentricities between 0.24 and 0.28.
Isonoe is estimated to be about 4 km in diameter, assuming an albedo of 4%. Like most other Carme group members (except Kalyke), it appears light red in color, with B–V and V–R color indices of 0.78 ± 0.05 and 0.53 ± 0.04, similar to D-type asteroids.
The moon likely did not form near Jupiter but was captured later. Along with the rest of the Carme group, it is probably a remnant of a broken, captured heliocentric asteroid.
Quick Facts
- Pronounced
- aɪ · ˈ · s · ɒ · n · oʊ · . · iː
- Adjective
- Isonoean ˌ · aɪ · s · ə · n · oʊ · ˈ · iː · ə · n
- Named After
- Ισονόη Isonoē
- Mpc Name
- Jupiter XXVI
- Discoverer
- Scott S. Sheppard / David C. Jewitt / Yanga R. Fernandez / Eugene A. Magnier
- Discovery Site
- Mauna Kea Observatory
- Discovered
- 23 November 2000
- Satellite Of
- Jupiter
- Group
- Carme group
- Epoch
- 23 March 2018 (JD 2458200.5)
- Observation Arc
- 2000 · 2024 / 2024-12-03 (last obs)
- Semimajor
- 0.1559024 AU
Facts from the source article.
Lore & Background
Isonoe was discovered in 2000 by a team of astronomers from the University of Hawaiʻi led by Scott S. Sheppard, and was given the temporary designation S/2000 J 6. It was named in October 2002 after Isonoe, one of the Danaïdes in Greek mythology and a lover of Zeus (Jupiter).
Orbiting Jupiter at an average distance of 23,322,670 km in 691.62 days, Isonoe has a retrograde orbit with an inclination of 165° to the ecliptic and an eccentricity of 0.226. It belongs to the Carme group, a set of irregular retrograde moons that orbit Jupiter between 22.7 and 23.5 million km, with inclinations around 165° and eccentricities between 0.24 and 0.28.
Physically, Isonoe has an estimated diameter of 4 kilometers, assuming an albedo of 4%. Like most other members of the Carme group (with the exception of Kalyke), it is light red in color, with color indices similar to D-type asteroids. It probably did not form near Jupiter but was later captured, and like other Carme group members, it is likely the remnant of a broken, captured heliocentric asteroid.
Reader's Guide
Isonoe's significance lies in its membership in the Carme group, a tightly clustered set of irregular retrograde moons of Jupiter. The article indicates that these moons share similar orbital characteristics—distances between 22.7 and 23.5 million km, inclinations around 165°, and eccentricities between 0.24 and 0.28—which strongly suggests a common origin. Isonoe, like the other Carme group members, is probably not a body that formed near Jupiter but was instead captured from the heliocentric asteroid population and later fragmented. Its light red color, similar to D-type asteroids, supports this interpretation. The discovery by a team from the University of Hawaiʻi led by Scott S. Sheppard in 2000, and its naming in October 2002 after a figure from Greek mythology, place it within the broader context of the systematic exploration of Jupiter's outer moon system. As a small moon with a diameter of only 4 kilometers, Isonoe exemplifies the many tiny, irregular satellites that provide clues to the dynamic history of the Jovian system and the capture of small bodies from the early solar system.
More in Moons of Jupiter 1-24
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