Asteroid Ring Occultation & Dynamics Lab

Simulate stellar occultations by ringed centaurs and small outer solar system bodies. Model how rings change over a decade through varying aspect angles, particle collisions, shepherd resonances, and optical depth evolution.

EPOCH: 2013 Discovery

Target Minor Body Presets 10-yr verified cases

Geometry & Decade Aspect

Ring Opening / Tilt Angle (B) 34.0°

Controls projected apparent ring thickness and path chord length as viewed from Earth.

Impact Parameter (b) 35 km

Star chord offset perpendicular to shadow path (0 = central transit).

Shadow Velocity (v_rel) 22.4 km/s

Ring Optical Depth & Physics

Inner Ring Optical Depth (τ₁) 0.40

Normal optical depth of main dense ring (e.g. C1R).

Outer Ring Optical Depth (τ₂) 0.06

Secondary diffuse ring or outer resonance component.

Shepherd Moonlet Resonance 3:1 ILR

0: Unconfined (spreading) • 1: Weak • 2: 3:1 Inner Lindblad • 3: 4:3 Strong Resonant

Telescope SNR (Noise level) SNR 65

Ready to synthesize occultation chords.

SIMULATION • Projected Minor Body & Occultation Chords

SKY PLANE (Observer Projection)

t = 0.00s

DYNAMICAL EQUATORIAL VIEW & ROCHE LIMIT

R_Roche: 310 km

Normalized Flux (F / F₀) vs Time (s) Total Ingress/Egress Duration: 24.2 s

Equivalent Width (W_τ) 2.84 km ∫ (1 - e^-τ/μ) dr

Apparent Opacity Peak 44.8% Ring 1 flux transmission

Shepherd Mass Limit 1.2 × 10¹² kg ~1.2 km moonlet req.

Roche Limit Ratio 0.82 R_L Inside Roche boundary

Reconstructed Radial Optical Depth Profile: τ(r)

Inverted directly from occultation transmission: τ(r) = -μ · ln(F / F₀)

10-Year Baseline Overlay

Dynamical Insight: Over the 2013–2023 decade, Chariklo's rings decreased in apparent opening angle from B = 34° toward edge-on (~5°), resulting in higher projected line-of-sight optical depth (μ = sin B) and noticeable radial redistribution from Poynting-Robertson drag and resonant confinement.

1. Stellar Occultation Technique

Because centaurs are tiny (100–300 km) and tens of astronomical units away, direct optical imaging cannot resolve ring gaps. When the system passes between Earth and a distant star, the star acts as an infinitely sharp pinhole, scanning the rings with kilometer-scale spatial resolution.

2. Why Rings Change Over a Decade

Centaurs have short orbital periods (Chariklo ~63 years). Over 10 years, our viewing geometry swings dramatically from open pole-on rings to an edge-on view, making rings seem to vanish. Additionally, tidal torques and shepherd moonlets continuously stir dust bands and sculpt resonant gaps.

3. The Quaoar Roche Conundrum

In 2023, rings were confirmed around dwarf planet Quaoar at 4,100 km—well beyond its classical Roche limit of 1,780 km. Where particles should accrete into a moonlet within decades, elastic collisions and cryogenic ice properties prevent clumping, preserving the ring.