Jupiter and the Jovian Planets

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Jupiter and the Jovian Planets
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Formation of Jovian Planets

• Step 1 ? Accretion of planetesimals to form
  large Earth-like solid planet cores of rocks,
  iron, nickel
• Masses of Cores in terms of Earths mass
• Jupiter - 28
• Saturn - 17
• Uranus - 3.5
• Neptune - 4.3
• Step 2 ? Lighter gases condense on to the planet
  cores due to gravity and cold temperatures
  

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Jupiter Interior
Molecular Hydrogen
Metallic Hydrogen
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Saturn Interior
Molecular Hydrogen
Metallic Hydrogen
Ice
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Interiors of Jupiter and Saturn
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Interiors of Uranus Neptune
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Jupiter
Saturn
Metallic Hydrogen
Neptune
Uranus
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Temperature (pressure) in Jupiter rises faster
than in Saturn with depth
Although T and P are high in the cores, not
sufficient for nuclear fusion like stars Require
millions of degrees!
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Jupiter A Failed Star

• Jupiter is 318 times more massive than the
  Earth yet, it is 80 times too small to become a
  star, i.e. make nuclear energy from fusion like
  the Sun
• But Jupiter (and Saturn) emits roughly twice the
  energy it receives from the Sun
• Energy derives from self-gravity ? gravitational
  compression of the interior (Jupiter shrinks
  about an inch per century)
• Surface T 124 K, but expected 109 K (assuming
  Sun to be the only source)
• Jupiter radiates (124 / 109)4 1.7 times more
  energy than would be expected

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Jupiter The King of Planets
Stripes, What are they?
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The Red Spot What is it?
First seen by Galileo, over 350 years ago ! Twice
the size of the Earth
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A long lasting (over 300 years!!), internally
powered, cyclonic storm (but what sustains it?)
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Rapid rotation of Jupiter
Period 10 hrs ? In spite of its size (318 times
more massive than the Earth) it rotates 2 ½ times
faster. But there is very little tilt of rotation
axis (3 degrees) ? No Seasons !
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Internal energy source ?Strong convection
currents
What provides the internal energy source ?
Self-gravity!
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Jupiter Vital Statistics

• Equatorial radius 71,500 Kms
• Orbital period 11.86 Earth years
• Mean density 1.33 g/cc (3.5 times lower than
  Earths)
• Indicates mostly H2 interior, but at tremendous
  pressure ? Metallic Hydrogen (conducts
  electricity!), up to about 20,000 Kms into the
  center
• Alternating lighter and darker stripes on the
  surface are zones of rising (warmer) and falling
  (cooler) material

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Vertical Convection Belts and Zones
Cloud patterns are at different temperatures
(altitudes) and wind speeds tremendous wind
shear (reverse direction at different altitudes)
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Jovian Interior
Mostly metallic hydrogen ? electrically
conducting interior ? huge magnetic field
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Jupiters Interior

• Most of Jupiter is about 40,000 mile deep ocean
  of liquid hydrogen
• But it is mostly metallic H2 high density and
  pressure compress the H2 molecule so that they
  share electrons, i.e. electron can move around
  like in a metal ? conduct electricity
• Core is solid ice, rock, iron, nickel at very
  high pressure (1 billion lbs / sq. inch)
• - core itself is about 28 x Earths mass
• - temperature 50,000 F

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Conditions inside Jupiter

• Composition like the Sun mostly H, He
• Atmosphere 500 miles thick, largely H2, He, and
  CH4, NH3, H2O
• Very low mean density of 1.33 g/cc (including
  compressed core) ? planet must be largely liquid
• Surface is largely top of liquid hydrogen
  ocean (Jovian planets have no solid surface),
  where Air pressure is 500 x Earths, and
  temperature of 4000 F
• Equator and poles do not rotate at same rate
  (oblate shape) 9h 50min and 9h 55 min
  respectively
• Huge magnetic field, why?

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Jovian Magnetosphere
Note that scale on bottom right! Jupiters
magnetic field is 20,000 times stronger than
Earths
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Jupiters Magnetic Field

• 20,000 times stronger than Earths, due to
  convection in liquid metallic H2 interior
  convection is due to rapid rotation
• Fast electrons produced when the solar wind
  hits Jupiters magnetosphere
• Lethal rays density of particles is thousands
  of times fatal human dosage
• Magnetosphere extends up to Saturn, 5 AU away

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Jupiter and the 4 Galilean MoonsIo, Europa,
Ganymede, Callisto
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Relative sizes of Galilean Moons
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Galilean Moons Io, Europa, Ganymede, Callisto
?Rocky to Icy
(Ganymede is the largest moon in the solar system)
Io and Europa are mostly rocky but Ganymede and
Callisto have more ices Densities 3.6, 3.0,
1.9, 1.8 g/cc respectively.
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Jovian Moons

• In addition to the 4 Galilean satellites, 12
  other moons of Jupiter have been discovered
• Owing to Jupiters tidal effects all Galilean
  moons are synchronous rotators they keep the
  same face towards Jupiter
• Voyager also found a ring around Jupiter, in
  between two small moons before Io
• Latest NASA probe of Jupiter is called Galileo

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IO

• Closest large moon to Jupiter
• Orbital period 42 hrs
• Surface has no impact craters, so less than 1
  milliion years old
• Many volcanic craters active volcanoes
• No water (too hot), but lots of sulfur on
  surface (sulfur condenses easily appears black
  when heated)

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Erupting volcanoes (taped live!)
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Hot-spots at volcanoes
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Ios Volcanic Activity

• Eight volcanoes seen by Voyager (many more seen
  since)
• Plumes rise 100 miles, spread over hundreds of
  miles
• Surface temp roughly 700 F near volcanoes, -250
  F away from them
• Caused by Jupiters tidal effect ? large land
  tides, up to 100 yards in height
• Friction inside Io produces heat and volcanic
  activity (squeezed like a ketchup bottle !)

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Pizza anyone ?
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Volcanic features on Io
Two-for-one pizza !!
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Typical volcanic feature on Io
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Ios orbit around JupiterSulfur emission
(spectral lines)
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Io and Jupiters Magnetic Field

• Magnetic field rotates with the planet, and
  electrifies the orbit of IO ? plasma (charged
  particles) torus surrounding orbit of IO
  contains Sulfur ions S (emission spectral lines
  detected on the Earth)

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Electrically charged atmosphere surrounding
Jupiter and orbit of Io
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Radio emission from around Jupiter

• Synchrotron radiation at radio wavelengths is
  produced by fast electrons
• from the magnetosphere
• Jupiters radio signals are detected on the
  earth! Interfere with radio
• Communications with CB, short-wave radio, radar,
  UHF TV, etc.

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Europa Ice rafts moving on liquid surface
Very thin Oxygen atmosphere has been detected on
Europa
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Surface comparison of Jovian Moons
Resolution
Rocky ? Icy
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Sizes and Distances of Galilean Satellites
Sizes relative to Earths Moon ( 1) 1.1, 0.9,
1.5, 1.4 respectively
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Many moons of Jupiter
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Jupiter Formation of Planetary Systems