Sponde.space

Irregular moon of Jupiter (retrograde) · Outer Jovian system · Pasiphae group

Sponde

Jupiter XXXVI · S/2001 J 5

A two-kilometre moon named after the goddess of the seventh hour — the hour of after-lunch libations.

Key factsStargazing kit picker
Sponde at a glance
Object typeIrregular, retrograde moon of Jupiter[1]
GroupPasiphae group[1]
DiscoveredDec. 9, 2001, Mauna Kea, Hawaii[2]
DiscoverersS. S. Sheppard, D. C. Jewitt, J. T. Kleyna[2]
NamedAugust 2003, after one of the Horae[1]
Diameter≈ 2 km[1]
Apojove5 Sept. 2026, ≈ 29.5 million km from Jupiter[1]
Mean distance≈ 23.5 million km from Jupiter[3]
Orbital period≈ 738 days[3]
Inclination≈ 149° (retrograde)[3]
Eccentricity≈ 0.32[3]

One of the tiniest

Sponde is about 2 km across — one of Jupiter’s smallest known moons. Sheppard’s team found it in 2001, designating it S/2001 J 5.[1]

Farthest point: September 2026

Sponde’s changing orbit brought it to apojove — its farthest point from Jupiter — on 5 September 2026, at about 0.197 AU (29.5 million km).[1]

Pasiphae group

Sponde belongs to the Pasiphae group, whose members are thought to have begun as one asteroid captured by Jupiter and broken by a collision, with Pasiphae its largest piece.[2]

The seventh hour

Sponde was named in August 2003 after one of the Horae (Hours), who presided over the seventh hour — libations poured after lunch. The Hours were daughters of Zeus and Themis.[1]

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Orbit

JPL’s mean elements put Sponde at about 23.5 million km on average, ranging from about 15.9 to 31.1 million km, with an orbit of 738 days.[3]

Jupiter Callisto (1.88 million km)Himalia (11.44 million km) farthest ≈ 31.1 million km closest ≈ 15.9 million km
Top-down orbit of Sponde to scale, computed from JPL orbital elements (a ≈ 23.54 million km, e ≈ 0.323).[3] Callisto and Himalia orbits shown for comparison.[3] Mean orbital elements; the real orbit is tilted steeply and shifts over time, so this top-down view flattens it onto one plane.

Your own hours under the sky

Sponde is far beyond amateur reach, but Jupiter itself is a rewarding first target. Our stargazing kit picker suggests starter gear.

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The Horae: goddesses of seasons and hours

The family of time goddesses behind Sponde’s name.

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Sponde’s September 2026 apojove

Why a moon with a 23.5-million-km mean distance swung out to 29.5 million km.

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Why do sources give different orbits for Sponde?

Osculating versus mean elements, explained.

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Sources

  1. Sponde (moon) — Wikipedia
  2. Sponde — NASA Science
  3. Planetary Satellite Mean Elements — NASA JPL Solar System Dynamics
  4. Horae — Wikipedia

Figures are rounded; where sources differ we note it. Spotted an error? Tell us.