Satellites of Uranus

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Satellites of Uranus Neptune - Outline
Inventory of Giant Planet Satellites Two
Different Types of Satellites regular and
irregular Review of Jovian and Saturnian
Satellites Satellites of Uranus regulars -
Titania Miranda irregulars shepherds -
Cordelia Ophelia Satellites of
Neptune irregulars - Triton Nereid regulars -
Proteus

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Inventory of Giant Planet Satellites
SATURN 31 known First in 1655 9 pre-Voyager 14
post-Voyager 1 in 2003 NEPTUNE 13 known First
in 1846 2 pre-Voyager 5 post-Voyager 1 in 2003
JUPITER 61 known First in 1610 13
pre-Voyager 45 post-Voyager 21 in
2003 URANUS 27 known First in 1787 5
pre-Voyager 11 post-Voyager 3 in 2003
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Two Different Types of Satellites
Regular Satellites low eccentricity - nearly
circular orbits low inclination - orbit in
nearly same plane (planets equator) all
orbit in prograde direction Irregular
Satellites large orbits - far from planet high
eccentricity inclination can orbit prograde
or retrograde usually small, irregularly shaped
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Regular Satellites of Jupiter
Europa
Io
Ganymede
Callisto
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Some Other Regular Satellites of Jupiter
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Satellites of Saturn
Titan
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Saturns Regular Satellite Titan
Nothing regular about it!
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The Planet Uranus
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Uranian Satellites
Regular Satellites 5 large ones Many small 2
found this year Irregular Satellites All lt 200
km 2 found this year
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The Uranian System
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Titania
Largest satellite of Uranus 1600 km long
trench Double walled crater
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Miranda
Small regular satellite, less than 500 km
diameter Patchwork of old and young
terrain Weird features 10 km deep
canyons trapezoid shapes Possible
explanations disruption, reaccretion ice rising
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Shepherd Satellites
Cordelia 13 km Ophelia 16 km
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Farewell Uranus
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The Planet Neptune
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Satellites of Neptune
Regular Satellites 6 known - all by Voyager All
small - Proteus (416 km) No large regular
satellites! Irregular Satellites Triton (2700
km) Nereid (340 km) 4 found 2002 1 found 2003
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Triton
Largest Neptunian satellite (2700 km) One of
largest in solar system, but IRREGULAR! Orbit is
retrograde Will eventually break up or impact
Neptune (108 years) Size, composition very
similar to Pluto Triton may have been captured
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Surface of Triton
Methane ice on surface N2 frost at poles covers
H2O ice Mean surface T 38 K (coldest in
S.S.) Cantelope terrain Very flat calderas
NH3-H2O eutectic melt (H2O melts 200 C
higher) Young surface - few craters (lt 4.5 x
109 yrs old)
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Atmosphere of Triton
Mostly N2 Some methane (CH4) Pressure 16 x
10-6 bars (microbars) Clouds, haze in upper
atmosphere - condensation or surface eruption
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Geysers on Triton
Active geysers observed by Voyager Composed of
N2 and dust particles Solid state greenhouse
Black streaks look like wind-blown fallout from
geysers Geysers 8 km high, 100 km long plumes
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Proteus and Nereid
Proteus is a regular (near circular
orbit) Nereid is an irregular (highly elliptical
orbit) Both have prograde orbits Both much
smaller than Triton Both irregular in shape
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Farewell Neptune
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Overview of Planetary Satellites
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THE END