Jupiter (Galileo)

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Jupiter (Galileo)
Saturn (Cassini)
Uranus (Hubble)
Neptune (Voyager)
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Everything You Need to Knowabout Ring Dynamics

• Newton Force Mass x Acceleration
• Law of Gravity
• Collisions
• Light-scattering Physics

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Main ring
Dark side High phase angle emphasizes tiny
dust grains
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Halo
Gossamer ring discovery
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Two Gossamer rings
Dusty rings must be sustained by source
bodies (seen or unseen)
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A B C
D
F
Encke Gap
Cassini Division
Lit side Low phase angle emphasizes large
bodies
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Earth!
Enceladus
F
G
Unique high-phase view!
E
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Geysers on Enceladus the source of the E ring
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Cassini On-line Resources

• Cassini Main Site
• http//saturn.jpl.nasa.gov/
• The latest raw images (cool!)
• http//saturn.jpl.nasa.gov/multimedia/images/raw/i
  ndex.cfm
• Imaging Team Web Site
• http//ciclops.org/

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The Opposition Surgeon Saturns rings. This
appears exactlyopposite to the directionto the
Sun, at phaseangle 0. The size of the surge
isa measure of how rough the particles are.
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The main rings of Uranus Imaged by Voyager 2 Low
phase big particles
epsilon
lambda
delta
gamma
eta
beta
alpha
6, 5, 4
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The rings of Uranus at high phase gt dust belts!
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Uranus in HST
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Long exposures reveal rings
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Overlaying frames shows moons
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Processing shows new rings!
nu ring
Mab the mu ring
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Adams ring
Leverrier ring
Fraternité
Egalité
Liberté
Courage
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Neptunes Changing Arcs

• The arcs can now be detected by Hubble and
  ground-based telescopes.
• Since 1989, the leading arcs have advanced
  forward and faded.
• Gravity effects of the nearby moon Galatea help
  to confine the arcs
• but the model is in trouble!

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Fun with Rings (1)

• Vertical Ripples

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Enhanced Galileo image of Jupiters main ring
A wireframe diagram showing vertical ripples in
a ring
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D ring ripples that have been winding up since
1984!
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Fun with Rings (2)

• Satellite Wakes

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Wavy edge of Encke Gap suggests an embedded moon.
Perturbed central ringlet
Color enhancement reveals spiral structure.
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The discovery of Pan in a sequence of
five Voyager images
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direction to Pan
A spectacular view of the Pan wake from Cassini
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Pan Imaged at Fine Resolution by Cassini
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The Discovery of Daphnis in the Keeler Gap The
wake is highly distorted
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Fun with Rings (3)

• Saturns Pathological F Ring

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Ophelia
Cordelia
Two moons shepherd the epsilon ring of Uranus
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Distant Voyager approach image Is the F ring
shepherded too?
Pandora
Prometheus
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Saturns Famous Braided Ring!
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A Selection of Cassini Images
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Prometheus produces a wake pattern just like Pan
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The aftermath of a ring impact?
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A recent, new feature 200 km inward from the
central ring
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2007 A Good Yearahead for Ring Science
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Cassini Extended MissionJuly 2008June 2010
Sample Tour Science planning is proceeding. Note
that this period includes the equinox on August
11, 2009!
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New Horizons at JupiterFebruary 28, 2007
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The first images of Jupiter from New
Horizons Range is 1 AU
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Sample planned images during the New Horizons
flyby
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2003
2005

• Edge-on viewing
• the main rings go dark
• search for shepherds
• see the dust rings better

2007 Equinox!
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Remember what Amalthea and Thebe do at Jupiter!
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December, 2007 the best ring viewing
geometry till 2022!