jupiter & jovian planets!...jovian planets: masses & sizes planet mass (kg) mass (earth masses)...
TRANSCRIPT
-
Jupiter & Jovian Planets!
The Outer Solar System.... differences?
-
Jovians: General Characteristics• BIG - (99.5% total mass!)
• Thick Atmospheres
• NO Solid Surfaces
• rock/ice inner core
• Rings
• LOTS of Satellites
• Rotate FAST (10-17 hours!)
-
Jovian Planets: Masses & SizesPlanet Mass
(kg)Mass (Earth masses)
Radius(km)
Radius(Earth Radii)
Jupiter 1.898 x 1027 317.7 71,492 11.2
Saturn 5.69 x 1026 95.2 60,268 9.4
Uranus 8.682 x 1025 14.5 25,559 4.0
Neptune 1.024 x 1026 17.1 24,764 3.9
-
Structure of Gas Giants
-
(Atmospheric) CompositionJupiter (and Saturn) are quite like the Sun:
(but very different from Earth)Percent by mass
Sun Jupiter Atmosphere
Saturn Atmosphere
Earth Atmosphere
Hydrogen 74% 75% 92%
-
What is Metallic H (& He)?Molecular H & He Metallic H & He
images fr. Burkhard Militzer
High pressure “squishes” molecules: electrons decouple; nuclei become degenerate
-
7
Jupiter & Saturn GLOW
Jupiter emits 2x as much energy as it receives from the Sun!! WHY??
-
Emission from Jupiter & Saturn
Conversion of Gravitational Potential Energy into Heat...
Just like PROTOSTARS!!
How did Jovians form??
-
JupiterMass ~ 318 Earth MassesSize - 11.2 Earth Radii (71,492 km)Density - 1.33 g/cc
New Horizons flyby
Jupiter is OBLATE
-
11
RSun = 9.7 RJupiterRJupiter = 11.2 REarth
RSun ~ 110 REarth
-
JupiterMass ~ 318 Earth MassesSize - 11.2 Earth Radii (71,492 km)Density - 1.33 g/cc
Orbital Period - 11.7 yearsOrbital Distance - 5.2 AURotation Period - 9.9 hours“Surface” T (1 bar) - 165 KCore T - >36,000 KObliquity - 3.1∘
New Horizons flyby
Jupiter is OBLATE
-
Jupiter - Bodacious B (Magnetic Field)
20,000x stronger than Earth!
passes through Saturn’s orbit
Why so Strong?
-
14
Spinning metallic hydrogen insides create strong magnetospheres
• Aurorae!
-
15
Spinning metallic hydrogen insides create strong magnetospheres
• Aurorae!
-
Jupiter’s AtmospherePercent by mass
Jupiter Atmosphere
Hydrogen 75%
Helium 24%
“Metals” 1%
Layered Structure: Methane, Ammonia & deep layer of water or ice droplets.
-
Weather on Jupiter
Belts and Zonesdifferential Rotation
(Fast) Differential Rotation!! 300-500 km/hr
Images from Cassini
Causes a lot of WEATHER!
-
Jupiter - Great Red SpotGiant Cyclone
discovered 1664
rotates in 6 days
BIGGER than Earth!
HST 2006
More than one!
-
19
Why is the Red Spot Red?
• The Red Spot is actually quite stuck up, (about 8km).
IR Data
Blue: Lower (warmer)
Yellow: Higher (cooler)
Galileo Spacecraft, 1996
-
20
Cassini
Looking inside CONTINENT-SIZED storms....
HST infrared images. March, 2007.
Cloud colorscorrespond to different T
-
Jupiter - Rings
Galileo image
-
Preview: Jupiter’s Moons 4 Galilean Satellites
AdrasteaAdrastea
Video:Universe, 23:04
-
Orbital Motion of the Galilean Satellites
Animation: A. Cidadao
Io: 1.8 daysEuropa: 3.6 days
Ganymede: 7.2 daysCallisto: 16.7 days
• Motion is Observable!•Io, Europa, Ganymede are in a Resonance
-
Composition of Galilean Satellites
Average Densities:
Io - 3.5 g/ccEuropa - 3.0 g/cc
Ganymede - 1.9 g/cc Callisto - 1.8 g/cc
???
Jupiter is a mini-Solar System!!Ices condense beyond Frost Line!
REMEMBER: Rocks - ~3.0 g/cc Ices - 1-2 g/cc
xt
-
(Many) Moons of Jupiter63 total at last count
59 outer satellites:
Likely captured asteroids (like Phobos & Deimos)
AdrasteaAdrastea
-
SaturnOrbital Period - 29.4 yearsRotation Period - 10.6 hoursOrbital Distance - 9.5 AU
Images from Cassini
Saturn is OBLATE
-
SaturnOrbital Period - 29.4 yearsRotation Period - 10.6 hoursOrbital Distance - 9.5 AU
Images from Cassini
“Surface” T (1 bar) - 134 KObliquity - 25.3 degrees
Seasons?
-
SaturnMass - 95.2 Earth MassesSize - 9.4 Earth Radii (60,268 km)Density - 0.69 g/cc !!
-
Saturn’s AtmospherePercent by mass
Saturn Atmosphere
Hydrogen 96%
Helium 3%
“Metals” 1%
•Bands Similar to Jupiter• why?
•Weather!Why so little Helium?
-
Helium Rain on Saturn?
H/He like oil & waterHelium Rain (Differentiation):
-contributes to internal heat-reduces He in atmosphere
-
Saturn Glows
Why?IR images from Cassini
-
Saturn’s Magnetic Field
-Fast Rotation-Liquid Metallic H/He
-
33
Saturn’s Rings
1655: Huygens interpreted as a disk...
1610: Galileo confused
-
34
Saturn’s Rings1676: Cassini saw the gap in the rings (now named for him)
1883: 1st photo
Why does Saturn have rings??
-
35
Roche Limit (Edouard Roche, 1859)
• A distance from a massive body inside which tidal stresses can break up bodies.
• Most of the ring systems are inside the Roche limit
Tides!
-
36
Roche Limit (Edouard Roche, 1859)• Comet Shoemaker-
Levy 9 broke up inside Jupiter’s Roche limit:
-
Made of dust and water ice particles
-
Moons of Saturn
61 at last count (most recent 2007)
1 Relatively large Satellite
6 Moderate-sized satellites
53 small satellites (similar to Jupiter’s)
AdrasteaAdrastea