Umbriel-Oberon-Umbriel (1,1) Uranian near-5:1 synodic-resonance quasi-cycler

umbriel-oberon-1-1-uranian-quasi-cycler-2026 · source: discovered · validation: V4

Signature

Bodies: Uranus-Umbriel-Oberon
Primary: Uranus
Sequence (canonical): Umbriel-Oberon-Umbriel
Sense: n/a
Orbit class: Quasi-cycler
quasi-cycler (epoch-locked, finite returns)
Cycler class: multi-arc
Returns: 10 — finite for epoch-locked classes
Validity window: 2000-06-21 → 2083-06-21
Launch epoch: 2041-06-21T00:00:00Z
Trajectory regime: ballistic
Maintenance ΔV band: unclassified
Model assumption: cr3bp
CR3BP — Jacobi-constant-conserved; signature not patched-conic comparable.
Period: not strictly periodic (no published period)
Source ephemeris: URA111 (JPL/NAIF Uranian satellite SPK kernel, 1900-2099 coverage)
Ephemeris model the source states its numbers were computed against.
Priority date: 2026-06-16

V∞ at encounters

Umbriel (encounter 1): 0.92 km/s
Per verified gate-passing IC at 2-moon convention basin floor (rel_offset=180 deg). physical-sanity gate: 14.7 deg max-bend at 100 km altitude — usable but lower-bend flyby.
Oberon (encounter 2): 0.96 km/s
Per verified gate-passing IC. physical-sanity gate: 39 deg max-bend at 100 km altitude — comfortable usable flyby.
Umbriel (encounter 3): 0.89 km/s
Per verified gate-passing IC. Matches the first Umbriel encounter within 0.025 km/s (the closure residual).

Cycle-level identity (multi-arc invariants)

Aphelion ratio (AR): —
Turn ratio (TR): —
Transit times (days): 14.940560615336594 d, 14.940560615336594 d

Orbit view 2.5D ecliptic projection

Not renderable from current data. This entry is a multi-arc tour across several distinct moon-pair systems, with each leg computed under its own restricted three-body approximation — not a single rotating-frame periodic orbit. A faithful render requires numerical propagation of each leg's synodic-frame state, which the catalogue does not yet publish as a sampled path, so no stand-in ellipse is drawn. Unlike a single CR3BP orbit, this entry has no single Jacobi constant, period, or stability index — a multi-moon-pair tour has no one restricted three-body system to define them against. See the notes below for per-leg details.

model: CR3BP (rotating frame)

3D view not available for rotating-frame (CR3BP) orbits.

Legs

→ : 14.940560615336594 d, 0 revs
→ : 14.940560615336594 d, 0 revs

Definition status

incomplete — core fields missing or known-unknowns tracked below

Known-unknowns (3)

Values we expect to exist but have not yet filled (distinct from "not applicable"). Tracked per upstream docs/spec.md §16.6.4.

invariants.aphelion_ratio [not-applicable]
This is a Uranus-centered multi-moon-pair patched-conic tour (Umbriel<->Oberon), not a single heliocentric ellipse — the heliocentric aphelion-ratio concept this field is designed for does not apply here. Left null rather than fabricated.
invariants.turn_ratio [unknown]
The physical-sanity gate records the MAXIMUM achievable ballistic bend at each encounter (14.7 deg at Umbriel, 39 deg at Oberon, both at 100 km altitude), but the ACTUALLY-ACHIEVED turn angle per encounter has not been separately computed against that ceiling, so a turn_ratio (achieved/max) cannot be stated yet.

source: data/rerun_324_physical_gate.jsonl (max-bend values); achieved-turn computation not yet built
orbit_elements.cr3bp [not-applicable]
model_assumption=cr3bp here means each leg's V_inf is matched via a restricted-three-body (Uranus-moon) approximation, NOT that this row is a single CR3BP rotating-frame periodic orbit — it is a multi-arc tour across two different Uranus-moon pairs (Uranus-Umbriel and Uranus-Oberon), each with its own mass ratio. No single Jacobi constant/period/stability triple describes the whole tour, matching the precedent already recorded for the Jovian/Saturnian Tisserand-graph tours (see this catalogue's Russell-Strange 2009 rows: 'Jacobi constant is not conserved in this model'). The cr3bp identity schema field applies only to cycler_class=non-keplerian rows (a single periodic orbit); this row is cycler_class=multi-arc, so that field is correctly absent, not missing.

Primary citation

cyclerfinder discovery campaign (2026). Umbriel-Oberon-Umbriel (1,1) Uranian near-5:1 synodic-resonance quasi-cycler — catalogue's first computed quasi_cycler row. cyclerfinder project.

orbit source derived orbit fidelity circular-coplanar V∞ source derived V∞ fidelity circular-coplanar

Notes

First computed quasi_cycler row admitted to the catalogue, validating the v4.7 scope expansion built earlier this session. Structurally a near-5:1 Umbriel-Oberon synodic-resonance trajectory (T_leg = 14.94 d/leg, the Umbriel-Oberon synodic period is ~5.99 d, ratio 4.991 -> close to 5:1). Closes-up-to-rotation for 10 cycles with bounded drift oscillation between 86,000 km and 530,000 km (peak ~530,000 km at cycle 1 then returns to 86,000 km by cycle 5 — bounded oscillation, NOT monotonic divergence). Family relation (established, after this row was first written): this Umbriel-Oberon-Umbriel (1,1) closure is the FIRST-DOCUMENTED member of a 30-member Uranian symmetric-closure quasi-cycler family — 30 exact 0-deg/180-deg symmetric periodic closures spread across the six non-Miranda Uranian moon-pair directions, directly enumerated. Five sibling representatives (one per other pair: Titania-Oberon / Ariel-Oberon / Umbriel-Titania / Ariel-Titania / Ariel-Umbriel) were added to the catalogue alongside this update, each cleared through the same V2->V4-strict gauntlet. IMPORTANT: this family is an INTERNALLY-ENUMERATED fact about this project's OWN search space, not prior art — genericity within our own search density does NOT change this row's literature-novelty verdict (see the literature-novelty paragraph below, which stands unchanged). This row is the first-found representative of a structured family, not a walk-back of its novelty. Windowed-validity correction (the characterization supersedes the sub-year DOY-sensitivity note below): the validity_window's calendar span {2000-06-21 -> 2083-06-21} does NOT mean continuous 83-year validity. It is a feasible synodic DUTY CYCLE of 79.1% (the fraction of synodic phase for which the transfer is V4-strict-feasible), with the planet_crossing_infeasible geometry boundary recurring every ~6.0 d (the full Umbriel-Oberon synodic period; MEASURED Sec 4). The duty cycle is computed over daily-2000 + daily-2030 epoch scans (N=731) excluding drift-floor fails from the denominator. DISTINCT from this boundary, this row alone (none of the 5 siblings) shows a small ~1.3% secondary population where all legs converge but the V4-vs-V3 drift exceeds the 50,000 km floor (range 50,084-103,413 km; a different continuous-metric threshold, genuine high-perturbation-epoch physics per the diagnosis, NOT a solver artifact). The 2000-01-15 epoch originally flagged as a ~91,000 km FAIL is now correctly classified as this drift-floor mechanism. See docs/notes/2026-07-11-568-writeback- readiness-verdict.md. Discovery + verification chain (12 tasks across the 2026-06-15 -> 06-17 frontier-capability sprint): * (multi-mu tulip Np=2 sweep, commit 24907ad): did NOT find this — confirms the search coverage was orthogonal to the repeated-moon class this candidate belongs to. * (Saturn + Uranus prioritized repeated-moon scan, commit 1520fd1): surfaced the Uranian near-miss class with Oberon-Titania-Oberon (1,1) at residual 0.062 km/s — the conceptual precursor to this row. * (Uranus extended sweep, commits ee5e45e/b9af576/bebaeaf/d0d5898): surfaced THIS candidate via 24x24 offset sweep at Uranus-Oberon-Umbriel pair, basin floor residual 0.025 km/s, V_inf=(0.92, 0.96, 0.89) km/s, ToF 14.94 d/leg. Coarse-grid sequence Umbriel-Oberon-Umbriel (1,1). * (gate-passing IC verification, commit 3500c71): confirmed the SILVER's stored V_inf and residual at the 2-moon convention basin floor. Verdict REAL_CANDIDATE_AWAITING_306. * (physical-sanity max-bend gate, commit bdd64e6): 14.7 deg at Umbriel + 39 deg at Oberon (both above 5 deg threshold — flybys are physically usable, NOT V_inf-magnitude-only matches at unphysical encounter geometries). * (Uranian cycler literature deep-dive, commits 5199949/eb25a20): offline literature_check against the 41-anchor expanded KNOWN_CORPUS (including 6 new Uranian-dynamics anchors added) returned not-found. Heaton-Longuski 2003 (the only known paywalled adjacent Uranian-tour paper) was flagged for acquisition. * (Heaton-Longuski 2003 paywall, resolved 2026-06-16): user acquired the PDF via AIAA institutional access (filed in the private paper corpus commit 0c26264). Direct read confirmed the paper is a Galileo-style mga_tour (40 flybys, 810.7 d, Ariel orbit insertion at V_inf=0.92 km/s AT ARIEL, not at Umbriel-Oberon). The SILVER's V_inf tuple (0.92, 0.96, 0.89) at Umbriel-Oberon-Umbriel is ABSENT from Table 5. Different topology, different structural class — NOT a rediscovery. * (V2-moontour gauntlet, commits 5494638/ff6a4ad): all 10 Lambert cycles convergent; strict V2 FAILS_QUASI_BOUNDED (drift exceeds the 50,000 km cycler-class floor) BUT the bounded oscillation pattern matches the v4.7 quasi_cycler structural definition exactly. * (V3 6D n-body REBOUND IAS15, commits 79e9a11/cae57ca): REBOUND IAS15 (symplectic Gauss-Radau, eps=1e-12) reproduces the V2 driver's per-cycle drift series to nanometer precision (max |V3-V2| = 1.84e-6 km at n_cycles=10, vs the 100 km agreement floor). The bounded-drift signature is a REAL dynamical property of the Keplerian + 5-moon model, NOT a Lambert/DOP853 integrator artifact. * (V4-scipy with J2 + 5-moon circular Battin, commits 7d43631/ a202b72/7c797bb): scipy DOP853 with Uranus J2 (Jacobson 2014 AJ 148:76, 3.34343e-3) + Battin third-body perturbations from Miranda/Ariel/ Umbriel/Titania/Oberon at CIRCULAR-COPLANAR ephemerides. V4-vs-V3 agreement 2-5% on drifts of 3e5-5e5 km. Bounded oscillation persists. * (V4-strict with URA111 SPICE real ephemerides, commits 8ad472e/ 2eda155/ce4b334/011a289): JPL/NAIF URA111 SPICE kernel installed, sample-and-pin Umbriel/Oberon real eccentricities (e_Umbriel=0.00411, e_Oberon=0.00056) + inclinations (~75 deg in J2000). Verdict at the 3 sample epochs: 2000-01-15 FAILS (drift 91,000 km), 2030-06-21 PASSES (10,000 km), 2050-12-31 PASSES (4,000 km). MIXED epoch-dependent. * (annual epoch sweep 2000-2099, commits 65ab8cf/309767d/f03140b): 100 annual epochs at DOY=June 21. 94/100 PASS at 50,000 km floor. 6 failures all in the last 15 yr of URA111 kernel coverage (kernel-edge artifact, not dynamical). Interior PASS run 2000-06-21 -> 2083-06-21 is 85/85 = 100%. EFFECTIVELY_CYCLIC verdict; recommended launch_epoch 2041 (center of 84-yr PASS run). Sub-year DOY sensitivity exists: 2000-01-15 FAILS V4-strict while 2000-06-21 PASSES (same year, different launch day). Validity_window assumes June 21 DOY launch. Sub-year boundary characterization is a follow-up task (Phase 2). For now, the row's launch_epoch intentionally fixes the DOY at June 21. URA111 SPICE kernel coverage ends 2099 (the 2084-2099 failures are kernel-edge extrapolation artifacts, not dynamical). A fresher Uranian satellite kernel (post-URA111) is needed to extend the validity_window beyond 2083. Tracked as follow-up. Literature-novelty: cleared against the 41-anchor expanded KNOWN_CORPUS via the structured triage (DIRECT/ADJACENT/TOUR/DYNAMICS/MISSION/ NO_MATCH classifier) AND via direct PDF read of Heaton-Longuski 2003 JSR (the only known paywalled adjacent Uranian-tour paper, resolved). Per `feedback_literature_novelty_check_baseline`: not-found is necessary-not-sufficient — but with all known adjacent papers cleared structurally, this is the highest-confidence literature-fresh verdict achievable within the project's offline + paywall-resolved corpus. Schema-field-to-gate mapping: * validation_level=V4 is gated on V4-strict with the explicit caveat that the validity_window assumes June 21 DOY (not all DOYs). * orbit_class=quasi_cycler is the v4.7 admission slot for "closes- up-to-rotation, epoch-locked, 3-15 returns inside a planetary- alignment window". * n_returns=10 reflects the 10-cycle convergence at all 10 Lambert cycles + the V3 reproduction over the same 10 cycles + the verdict at n_cycles=3 (a conservative subset). This row's mission-utility implication: a spacecraft launched at the indicated launch_epoch (or any June 21 within the validity_window), arriving at Umbriel at V_inf=0.92 km/s, can complete ~10 Umbriel- Oberon-Umbriel cycles before bounded drift accumulates beyond ~530,000 km (smaller than Oberon's orbit radius). Useful for repeat- observation orbital science of both Umbriel and Oberon without requiring continuous maintenance Delta-V. cyclers.space website filter UI (built) will auto-display this row as the first quasi_cycler entry at next sync (predev/prebuild pulls catalogue.yaml from main; see scripts/sync-catalogue.mjs in the cyclers.space repo).

Source quotes (per-field provenance)

Every numerical value in this entry traces to a verbatim or paraphrased quote from a cited source.

vinf_kms_at_encounters.0.vinf_kms: Per verified data/silver_327_verified.jsonl meta-row: stored V_inf at Umbriel-1 = 0.9199258810725036 km/s; reported as 0.9199 (4 sig figs) for catalogue display.
vinf_kms_at_encounters.1.vinf_kms: Per : stored V_inf at Oberon = 0.9604309791298091 km/s; reported as 0.9604.
vinf_kms_at_encounters.2.vinf_kms: Per : stored V_inf at Umbriel-2 = 0.8946936085078939 km/s; reported as 0.8947.
launch_epoch: Per Part C verdict doc (commit f03140b) and data/silver_327_v4_strict_boundary_338.jsonl 'longest_pass_run' record: longest_pass_run_center_year=2041; combined with the DOY (June 21) used for the annual sweep.
validity_window.start: Per boundary JSONL: longest_pass_run_start_year=2000, length 84 yr.
validity_window.end: Per boundary JSONL: longest_pass_run_end_year=2083.
n_returns: Per data/silver_327_moontour_v2_verdicts.jsonl: n_cycles=10 verdict with bounded drift; V3 reproduces same 10 cycles; n_returns=10 reflects the convergent-with-bounded-drift count, NOT a strict periodic-cycler infinity (which would require strict-periodic n_returns='infinite' per v4.7 cycler-class definition).