S/2018 J 4

A confirmed moon in the Jupiter system.

Unnamed · S/2018 J 4

Snapshot 2026-09-09 · catalog 1.0.0

Explore S/2018 J 4 in Orrery

Physical measurements

Mean radius
— No value in the admitted source set.
GM · gravitational parameter
— No value in the admitted source set.
Mass
— Mass requires an admitted GM estimate.
Mean density
— No value in the admitted source set.

Orbit descriptions

Mean elements describe an average orbit. They are not positions for a chosen date.

JUP347 · ecliptic plane · 2000-01-01.5 TDB
Semimajor axis
16,328,500 km
Sidereal period
426.265 days
Eccentricity
0.177
Inclination to reference plane
50.2°
Argument of periapsis
285°
Mean anomaly
138.3°
Ascending node
52.1°
Apsidal / nodal precession periods
297.2 / 239.7 years
Reference-plane pole RA / Dec
— / —°
Plane tilt to parent equator
—°
Reference center
Not specified in this summary sourceThe summary table identifies a parent system but does not explicitly specify the reference center for each solution. Do not infer a physical-primary center, especially for Pluto’s circumbinary moons.

Orientation

No supported orientation model in the admitted PCK source.

Identity & availability

Stable catalog ID
s-2018-j-4
JPL / NAIF satellite ID
55520
Names & designations
S/2018 J 4
Discovery / rediscovery years
2018S.S. Sheppard

No validated dated trajectory admitted in catalog 1.0.0. Mean elements are not ephemerides.

No image or global texture admitted in this catalog release.No environment measurements admitted in this catalog release.

Sources & evidence

  1. JPL discovery circumstancestable tr[106] (zero-based); jupiter / S/2018 J 4 · References: MPEC 2023-B51
  2. MPC planetary satellite listitems[222]; S/2018 J 4
  3. JPL mean orbital elements#sat_elem row ID=94; Jupiter / S2018_J_4 / NAIF 55520 · References: 47

Full catalog, uncertainty and source manifests · All Jupiter moons · Moon model limits