Wavelet Analysis of the Huygens Ringlet and the C Ring.
June 9th 2009
UVIS Team Meeting
Kevin BAILLIE
Josh COLWELL
Image: NASA/JPL/SSI
1. Huygens Ringlet
Cassini Division (~ 4600 km)
Huygens Gap (~ 400 km)
Huygens Ringlet (< 25 km)
B­ring outer edge
Image: NASA/JPL/SSI
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1.1 Huygens Ringlet occultation profiles
Diversity of occultation profiles in the Huygens Ringlet:
Origin of these features and of this diversity ?
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1.2 Wavelet analysis of the Huygens Ringlet
A wavelet analysis on the Huygens ringlet region reveals recurrently a 1 km wavelength.
Can this signature be a satellite wake?
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1.3 Taking profit of 108 available occultations
Co­adding process : making periodic features more obvious by adding several occultation wavelet profile.
Since the wavelength is depending on the longitude of the satellite, the « random » distribution of longitude in the occultation can widen the signature.
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1.4 Co­adding wavelet analysis on the Huygens Ringlet
Wavelet analysis not conclusive on its own for the Huygens Ringlet.
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1.5 Satellite wakes model
Showalter et al., 1986 's wake model
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1.6 Constraints on a moon generating wakes in the Huygens Ringlet
Where would such a moon be in order to generate wakes with a 1km wavelength signature?
Such a moon would be at 100 – 250 km from the 1km wavelength.
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1.7 Positions of a potential moonlet
1st order calculus provides a maximum distance from the Huygens Ringlet around 200 km.
Huygens Ringlet + 200 km = outside Huygens Gap, but we would observe a gap on this moonlet's orbit.
Huygens Ringlet – 200 km = inside Huygens Gap, but no moon observed here yet.
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1.8 What if we should not be looking for a moonlet ?
Other features at the estimated distance may have significant impact on the Huygens Ringlet and maybe generate the observed 1km wavelength pattern.
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1.9 Similar Ringlet in the C­Ring
r = 1.470 Rs
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2. C­Ring wave signatures analysis
2.1 Wave signature detection using wavelet analysis in the C­Ring
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2. C­Ring wave signatures analysis
2.1 Wave signature detection using wavelet analysis in the C­Ring
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2.2 New unknown origin waves
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2.3 The Atlas 2:1 Density Wave (m=2)
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2.3 The Atlas 2:1 Density Wave (m=2)
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2.4 Surface mass density estimation in the Atlas 2:1 region
rL = 87646.4 km
λ = 1.4 km for r = 87646.4 km
σ = 0.139 g.cm­2 and τ = 0.05
Mass extinction coef =τ/σ = 0.360 (~0.1 for CD)
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2.5 σ / (m­1) at 84818 km
σ = 0.510 g.cm­2 at r = 84818.5 km
σ = 0.485 g.cm­2 at r = 84857.6 km
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2.5 σ / (m­1) at 89887 km
σ = 0.267 g.cm­2 at r = 89887.0 km
σ = 0.115 g.cm­2 at r = 89903.5 km
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2.5 σ / (m­1) at 86397 km
σ = 1.611 g.cm­2 at r = 86400.2 km
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2.7 Opacities and estimation of m
Assuming that opacity is constant leads to m:
m = 2.0
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2.92
6.12
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Conclusions and future work
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Wavelet analysis constrains the scenario of a moon origin in Huygens Ringlet features.
Non­moon origin (B­ring outer edge) to be modeled.
Co­adding wavelet analysis of the C­ring confirms wave structures and enables new wave structures detection of unknown origins.
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Origins to be determined.
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Surface­mass density and opacity derivation of these structures.
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1.5 Satellite wakes analysis in the Encke Gap region
The Encke Gap region in the A Ring
Image: NASA/JPL/SSI
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1.6 Encke region occultation profiles
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1.7 Wavelet analysis around the Encke Gap
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1.9 Co­adding wavelet analysis in the Encke region
Bonus: Resonance 15:14 with Prometheus at 133,163 km
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1.10 Which turned out to be Pan wakes
Pan (Encke Gap)
Daphnis (Keeler Gap)
Image: NASA/JPL/SSI
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