Post on 19-Jan-2016
Giant Planets
Jupiter
Saturn
Uranus
Neptune
Notes:
Read Chapter 11:
“Jovian Planet Systems”
Homework: in Mastering Astronomy due Friday.
Results from Midterm 1
• © 2005 Pearson Education Inc., publishing as Addison-Wesley
The Solar SystemTerrestrial (Rocky) Outer 4 Planets: Gaseous Giants
Spacecraft Reconnaisance1980’s: Voyager 1 & 2
Camera
Spectrometer
Visited all 4
giant planets
Measures spectral lines:
Chemical composition
Voyager SpacecraftMovie of Jupiter
Approach of Voyager SpacecraftIn Rotating Frame of Reference
• This is the original Voyager 'Blue Movie' (so named because it was built from blue filter images). It records Voyager 1's approach during a period of 60 Jupiter days. Notice the difference in speed and direction of the various zones of the atmosphere.
Voyager SpacecraftMovie of Jupiter:
In Rotating Frame of Reference
Galileo SpacecraftVisited Jupiter
• Launched from Space Shuttle 1989
Galileo SpacecraftArrived: 1995
2003:Dropped into Jupiter’s
Atmosphere:
Measure Chemical
Composition:
The 4 “Giant Planets”“Jovian Planets”
Much higher mass & radius than Earth, Venus, Mars.• No solid surfaces !!!
H & He (most common
atoms in universe)
(text: “hydrogen compounds” = water, methane, ammonia)
“Ice Giants”
Jupiter Saturn Uranus Neptune
All have rocky cores (silicates+iron) of 10-20 Earth masses
H & He H2O,
H & He
H2O,
H & He
Comparison of Sun’s and Jupiter’s composition (as measured by the
Galileo Probe)
Jupiter Sun Jupiter Sun
Remember: No solid surface and consists mostly of H & He.Distinct interior layers, defined by increasing density inward.
Fractional composition in mass %.
H 0.742 0.736 Ne 0.00023(3) 0.0018
He 0.231(4) 0.249 P < 0.00007 0.00001
C 0.009(2) 0.0029 S 0.00091(6) 0.00050
N < 0.012 0.00085 Ar < 0.00015 0.00007
O < 0.0035 0.0057 “Z” 0.027 0.015
• © 2005 Pearson Education Inc., publishing as Addison-Wesley
Jupiter – King of the PlanetsMass = 0.001 solar (318 Earth masses), Radius = 10.5 … 11.2 Earth radii, Density = 1.3 g/cc (1.3 x water)
Distance: 5.2AUOrbital Period: 11.8 years Rotation period: 9:55 hours.
Flattened Spheroid
11.2 RE
10.5 RE
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SaturnMass = 95 Earths (only 30% of Jupiter)
Radius = 9.4 Earths Density = 0.7 gram/cm3 (floats)Distance: 9.5 AUOrbital Period: 29.4 yearsRotation period: 10.6 hours.
Rings: Composed of billions of icy rocks and icy dust particles (water ice and silicates).
Interior of Jupiter and Saturn
“Phases” of Hydrogen: The Interiors of Jupiter & Saturn
Density
Tem
per
atu
re (
K)
Phases of Hydrogen
Computer Simulation: Molecular and Metallic hydrogen
Molecular hydrogen
Metallic hydrogen
• Electrons free to move• Electrons bound to molecules
“Phases” of Hydrogen: The Interiors of Jupiter & Saturn
Density
Tem
per
atu
re (
K)
Phases of Hydrogen
A New Probe of Jupiter: “Juno”Launch August 5, 2011
Interior of JupiterA New Probe: “Juno”
Surfaces of theGiant Planets
• © 2005 Pearson Education Inc., publishing as Addison-Wesley
Jupiter
Jupiter’s Atmospheric Properties
Rotation Period = 9 hours 55 minutes
(based on Jupiter’s magnetic field)
Cassini (2000)
Rotation Period = 9 hours 55 minutes
(based on Jupiter’s magnetic field)
Cassini (2000)
Jupiter’s Atmosphere
Cassini (2000)
Jupiter’s Atmosphere
Cassini (2000)
Convection on Jupiter:
• Warm air rises• Coriolis force
diverts path sideways
Coriolis force is due to
rotation of planet
• Jupiter rotates fast:
Period = 10 hours
Bands of JupiterWhat Causes them?
Red Spotin SouthernHemisphere
Winds of Jupiter’s Bands
• © 2005 Pearson Education Inc., publishing as Addison-Wesley
• © 2005 Pearson Education Inc., publishing as Addison-Wesley
A Hurricane that has
lasted 300 yearsGreat Red Spot
Giant red spot in motion
Giant red spot in motion
Red Oval in motion
Red Oval in motion
Cyclones and Anticyclones on Jupiter
Computer Simulation of Cyclone Formation
Red Spot Jr. spot formed from three white ovals and later turned red.
Cyclonic Motions
Coriolis effect: Motion fromHigh Pressure area
NorthernHemisphere
SouthernHemisphere
Cyclones: • Low pressure weather phenomena, • Winds blow inwards,• Typical storm systems on Earth• Rotate counter-clockwise on Northern
hemisphere, • Rotate on clockwise on Southern
hemisphere,
Anti-Cyclones: • High-pressure weather phenomena, • Winds blow outwards,• Example: Jupiter’s red spot• Rotate clockwise on Northern
hemisphere, • Rotate counter-clockwise on Southern
hemisphere,
Comparison of Cyclones and Anti-Cyclones
(A) Anti-cyclone on northern HS
(B) Cyclone on the northern HS
(C) Anti-cyclone on the southern HS
(D) Cyclone on the southern HS
What is this?
Cyclones: • Low pressure weather phenomena, • Winds blow inwards,• Typical storm systems on Earth• Rotate counter-clockwise on Northern
hemisphere, • Rotate on clockwise on Southern
hemisphere,
Anti-Cyclones: • High-pressure weather phenomena, • Winds blow outwards,• Example: Jupiter’s red spot• Rotate clockwise on Northern
hemisphere, • Rotate counter-clockwise on Southern
hemisphere,
Comparison of Cyclones and Anti-Cyclones
What is this?
(A) Anti-cyclone on northern HS
(B) Cyclone on the northern HS
(C) Anti-cyclone on the southern HS
(D) Cyclone on the southern HS
Jovian StormsRed Spot: A High Pressure Storm
• Analogous to hurricanes (low pressure systems, material flows in), but they rotate in the opposite direction because they high pressure systems where material flow out
Jupiter• the Great Red Spot• we are not sure why it is red
Neptune• the Great Dark Spot
Planet
Rotation
Uranus – Haze but any Clouds?Mass = 14.5 Earths Orbital Period: 84 years; Radius = 4.0 EarthsDensity = 1.3 gram/cm3 = 1.3 x water Distance: 19.2 AU Rotation period: 17.2 hours.
Visible Light Infrared Light (Thermal Emission)
Featureless in visible light, because clouds are below haze layer of methane (colder than Saturn).
Visible Light
• Featureless in visible light, because clouds
are below haze layer of methane (colder than Saturn).
Uranus – Yes Plenty of Clouds
Uranus – Yes Plenty of Clouds
NeptuneMass = 17 Earths
Radius = 3.9 Earths
Density = 1.76 x water
Distance: 30 AU
Orbital Period: 163 years;
Rotation period: 16.1 hours.
Cyclonic storms.
Uranus & Neptune Giants of H, He, and Water!
Rocky core (silicates+iron)
Liquid mixture of H2O, CH4, NH3 ices
Gaseous envelope of H, He, and some CH4
• © 2005 Pearson Education Inc., publishing as Addison-Wesley
Hydrostatic Equilibrium: Pressure balance
“Hydrostatic equilibrium” governs the structure of all planets. The inside has higher pressure and density because of the weight of the overlying material.
Pressure at any depth = gravitational weight of column above
Inside Giant PlanetsSaturn emits almost twice as much energy as it absorbs from the Sun.
• Neither Cooling nor Radioactivity can account for it• Saturn must a different “secret” heat source
Jupiter has 3x more mass than Saturn, but is only slightly larger in radius!• the added weight of H & He compresses the gases below to a higher density• like stacking pillows
• If Jupiter had 10x its mass, it would have same radius ! Add even more mass, and Jupiter would get smaller !
• Jupiter is as large as a planet can get.
• Uranus & Neptune have less mass than Saturn, yet
they have higher densities• They must be made of
denser material:
More Rock & Water !
How do you construct a model for Jupiter’s interior?
A typical Jupiter model is based on1) Hydrogen-helium
relationship between pressure-density-temperature
2) Abundance of all atoms from measurements (Galileo probe)
3) Gravitational “shape”, inferred from fly-by trajectories (Galileo & Cassini missions)
R
Rotation flattens shape —> Less pull on satellite at poles
Higher densitytoward center —> Exerts Point-like Gravitational Force
Track acceleration ofsatellites accurately
—> Density profile throughout interior
Determining the Density inside a Rotating PlanetUse Motion of Orbiting Satellites
Interactive Quiz
How would you land on Jupiter?
(A)With parachutes
(B) With thrust rockets
(C) With pontoons like a seaplane
(D) You cannot land on Jupiter.
How would you land on Jupiter?
(A)With parachutes
(B) With thrust rockets
(C) With pontoons like a seaplane
(D) You cannot land on Jupiter.
Interactive Quiz
How would you land on Jupiter?
(A)With parachutes
(B) With thrust rockets
(C) With pontoons like a seaplane
(D) You cannot land on Jupiter.
How would you land on Jupiter?
(A)With parachutes
(B) With thrust rockets
(C) With pontoons like a seaplane
(D) You cannot land on Jupiter.
Jupiter’s Moon: Io
A volcanic explosion can be seen silhouetted against dark space over Io's brilliant limb. Io more volcanically active than Earth.How many Jovian moons are there?
Thursday’s Lecture:
Moons orbiting the Giant Planets
• © 2005 Pearson Education Inc., publishing as Addison-Wesley
Jupiter – King of the Planets Radius = 10.5 … 11.2 Earth radii
Make a bigger Earth that has a radius 10 times larger. Assume the density would be the same, what would its mass be?
(A)The same, one Earth mass
(B) 10 Earth masses
(C) 100 Earth masses
(D) 1000 Earth masses
Make a bigger Earth that has a radius 10 times larger. Assume the density would be the same, what would its mass be?
(A)The same, one Earth mass
(B) 10 Earth masses
(C) 100 Earth masses
(D) 1000 Earth masses
• © 2005 Pearson Education Inc., publishing as Addison-Wesley
Jupiter – King of the Planets Radius = 10.5 … 11.2 Earth radii
Make a bigger Earth that has a radius 10 times larger. Assume the density would be the same, what would its mass be?
(A)The same, one Earth mass
(B) 10 Earth masses
(C) 100 Earth masses
(D) 1000 Earth masses
Make a bigger Earth that has a radius 10 times larger. Assume the density would be the same, what would its mass be?
(A)The same, one Earth mass
(B) 10 Earth masses
(C) 100 Earth masses
(D) 1000 Earth masses
But Jupiter’s mass is only 318 Earth masses. What does this tell us?
• © 2005 Pearson Education Inc., publishing as Addison-Wesley
Size of Rocky Planets
Make the Earth a 1000 times more massive. How large would its radius be?
(A)The same, one Earth radius
(B) 3 Earth radii
(C) 6 Earth radii
(D) 10 Earth radii
Make the Earth a 1000 times more massive. How large would its radius be?
(A)The same, one Earth radius
(B) 3 Earth radii
(C) 6 Earth radii
(D) 10 Earth radii
• © 2005 Pearson Education Inc., publishing as Addison-Wesley
Size of Rocky Planets
Make the Earth a 1000 times more massive. How large would its radius be?
(A)The same, one Earth radius
(B) 3 Earth radii (because of gravity!!)
(C) 6 Earth radii
(D) 10 Earth radii
Make the Earth a 1000 times more massive. How large would its radius be?
(A)The same, one Earth radius
(B) 3 Earth radii (because of gravity!!)
(C) 6 Earth radii
(D) 10 Earth radii
• © 2005 Pearson Education Inc., publishing as Addison-Wesley
Saturn’s
Storms
• © 2005 Pearson Education Inc., publishing as Addison-Wesley
After 15 years of winter on Saturn’s Northern hemisphere, spring arrives with gigantic storms
• © 2005 Pearson Education Inc., publishing as Addison-Wesley
scooter
Neptune’s
Storms
Jupiter’s Cloud Layers
Convection in the troposphere causes Jovian weather.
Warm gas rises to cooler altitudes, where it condenses to form clouds.
Three gases condense in the Jovian atmosphere:
• ammonia (NH3) (high altitude)
• ammonium hydrosulfide (NH4SH)
• water (H2O)
They condense at different temperatures, so their clouds form at different altitudes.
A
ltit
ude
abov
e cl
ouds
tops
(km
)
Temperature (°C)
The Jovian Atmospheres
The temperature profile of each planet determines the color of its appearance.
Cloud layers form where a particular gas condenses.
Saturn has the same cloud layers as Jupiter.
• they form deeper since Saturn is colder overall
• they are spread farther apart since Saturn has lower gravity
Uranus & Neptune• cold enough to form methane clouds
Aurora Borealis near Jupiter’s North Pole
• © 2005 Pearson Education Inc., publishing as Addison-Wesley
Auroral ZonesThe high energy particles come down the magnetic field lines and hit the atmosphere near the poles, causing the gases to glow. Just like on the Earth, this makes an “aurora” in a ring-like zone.
Magnetic FieldsJupiter Saturn
Uranus Neptune
• © 2005 Pearson Education Inc., publishing as Addison-Wesley
Jupiter’s Magnetosphere – Bigger than the Sun
Solar Wind
protons &
electrons
Jovian Magnetospheres
Saturn, Uranus, & Neptune have smaller & weaker magnetospheres.• fraction of electrically conducting material in interiors is smaller• Solar wind is weaker farther out, or else their magnetospheres would be even smaller• we can not explain the magnetic field tilts of Uranus & Neptune.
• © 2005 Pearson Education Inc., publishing as Addison-Wesley
Inside the Jovian PlanetsAll Jovian cores appear to be similar.
• made of rock, metal, and Hydrogen compounds• 10 x the mass of Earth
Uranus & Neptune captured less gas from the Solar nebula.• accretion of planetesimals took longer• not much time for gas capture before nebula was cleared out by Solar wind
Only Jupiter and Saturn have high enough pressure for H & He to exist in liquid and metallic states.
Quiz
If Jupiter formed in a protoplanetary disk that had twice as much dust in it:
(A)Would have a bigger core
(B) Might have more hydrogen
(C) Might have more metallic hydrogen
(D)All of the above
Quiz
If Jupiter formed in a protoplanetary disk that had twice as much dust it:
(A)Would have a bigger core
(B) Might have more hydrogen
(C) Might have more metallic hydrogen
(D)All of the above
• © 2005 Pearson Education Inc., publishing as Addison-Wesley
Why are the Jovian Planets Massive and Gaseous (H, He) ?
Formed beyond the frost line (3 AU): so cold that ice particles exist with silicate dust.
Ice and Dust collides, sticks grows into icy-rocky core. Core’s gravity captures H/He gasPlanet attracts ices and dust that orbitMoons formed out of these disks: A miniature solar system.
Young Solar System:
Gas & Dust
Young Jupiter