Local orbit radius
\[r=\frac{a(1-e^2)}{1+e\cos(\nu)}\]
Each tracked moon follows the same conic equation used for planetary orbits, with the parent planet as the focus.
Neptune moon system
Neptune moons in motion.
Neptune's system includes inner ring moons, massive captured Triton, and distant irregular satellites.
Neptune selected
- parent distance
- Sun distance AU
- speed
- period
- position
1.00x Earth view- from Sun - - disk - - light
Moon simulator is initializing. Drag to rotate, wheel to zoom, right-drag to pan.
Simulation basis
Mean orbit model
Triton's retrograde geometry and Nereid's high eccentricity are emphasized for orbit study.
Controls
Use the model
Drag rotates the scene, wheel zooms, right-drag pans, and the Full screen button expands the simulator. The time-rate selector can run from realtime seconds to one year per second.
The selected moon panel reports parent-relative distance, approximate Sun distance in AU, orbital speed, period, and current model angle.
Tracked moons
Interactive orbit data
These bodies have individual orbit tracks and selectable readouts in the simulator.
| Moon | Study note | Radius | Mean parent distance | Eccentricity | Period | Mean speed |
|---|---|---|---|---|---|---|
| Naiad | Innermost known Neptune moon in a fast orbit. | 33 km | 48,227 km | 0.0004 | 0.294 days | 11.9 km/s |
| Thalassa | Small inner moon just outside Naiad. | 41 km | 50,074 km | 0.0002 | 0.311 days | 11.7 km/s |
| Despina | Inner moon near Neptune's ring environment. | 75 km | 52,526 km | 0.0002 | 0.335 days | 11.4 km/s |
| Galatea | Ring-shepherding inner moon associated with ring arcs. | 88 km | 61,953 km | 0.0001 | 0.429 days | 10.5 km/s |
| Larissa | Irregularly shaped inner moon. | 97 km | 73,548 km | 0.0014 | 0.555 days | 9.6 km/s |
| Proteus | Large dark inner moon, close to the size where self-gravity rounds a body. | 210 km | 117,647 km | 0.0005 | 1.122 days | 7.6 km/s |
| Triton | Large captured Kuiper Belt object with retrograde orbit, nitrogen ice, and geyser-like plumes. | 1,353.4 km | 354,759 km | 1.6e-05 | 5.877 days | 4.39 km/s |
| Nereid | Highly eccentric outer moon, useful for explaining periapsis and apoapsis variation. | 170 km | 5,513,818 km | 0.75 | 360.14 days | 1.12 km/s |
Catalog coverage
Recorded names and groups
Naiad, Thalassa, Despina, Galatea, Larissa, Hippocamp, Proteus, Triton, Nereid, Halimede, Sao, Laomedeia, Psamathe, Neso, S/2002 N 5, S/2021 N 1
Dense irregular and provisional moon populations are represented as catalog shell markers when compact per-moon orbital elements are not bundled into this static site. Counts are preserved so the system scale remains visible without overloading the browser.
Mathematical model
Natural-satellite orbital model
Moon-system simulations use local two-body approximations around the parent planet. The layout is computed from orbital periods, eccentricities, inclinations, and mean distances rather than from a reference image.
Period consistency
\[n=\frac{2\pi}{P}\]
Mean motion n is derived from orbital period P. The animation phase is therefore tied to the catalog period and remains internally consistent.
Inclined orbit plane
\[\mathbf{r}_{\mathrm{scene}}=R_x(i)\,\mathbf{r}_{\mathrm{orbit}}\]
Inclination i rotates the moon's local orbital plane. This proves the visible path is a transform of the mathematical orbit, not a freehand ring.
Verification standard: the rendered object must be reproducible from stated equations, catalog parameters, or explicit geometric transforms. Visual reference images may inform presentation only; they are not the source of orbital positions, field vectors, accretion-disk gradients, timing, or engineering layout.
Limitations: browser scenes may use bounded scale, compressed distances, simplified two-body dynamics, schematic transfer curves, or educational approximations where full numerical ephemerides, CFD, finite-element models, or general-relativistic ray tracing are outside the page scope. Those simplifications are part of the model contract, not hidden image-based construction.