Saturn

1
Saturn

• Astronomy 311
• Professor Lee Carkner
• Lecture 18

2
Which of the following is a major component of
Jupiters clouds?

• Water
• Ammonia
• Molecular hydrogen
• a and b only
• a, b, and c

3
In what region does Jupiter generate its strong
magnetic field?

• Rock/ice core
• Liquid metallic hydrogen mantle
• Molecular hydrogen atmosphere
• Dust ring
• Alternating cloud bands

4
Saturn -- King of the Titans

• He was overthrown by Jupiter who became king of
  the gods
• Saturns symbol is the sickle

5
Viewing Saturn from Earth

• First viewed through a telescope by Galileo
• Modern telescopes reveal a series of rings and
  cloud patterns in Saturns atmosphere

6
Saturn Facts

• Size 9.5 Earth diameters
• Orbit 9.5 AU
• Description smaller, more distant Jupiter with
  rings

7
Viewing Saturn from Space

• Hubble Space Telescope has provided many images
• Orbiting Saturn to study it long term
• Dropped a probe (Huygens) into Titans atmosphere

8
Path of Cassini
9
Saturns Atmosphere

• Saturn has belts, zones, ovals and storms, but
  they are less distinct than on Jupiter
• Colors tend to be yellow, white and brown
• Saturn sometimes has storms that burst up from
  below

10
Composition of Atmosphere

• Top layer of Ammonia (NH3)
• Middle layer of Ammonium Hydrosulfide (NH4SH)
• We dont see all of the layers as clearly as we
  do on Jupiter

11
Saturns Dullness

• The temperature of Saturns atmosphere increases
  more slowly with depth than Jupiter because
• Due to weaker gravity the layers are more spread
  out
• As a result
• Upper layers obscure the deeper layers

12
Saturn and Jupiters Atmospheric Structure
13
Saturns Heat

• Saturn is smaller than Jupiter and should have
  radiated much of its heat away by now
• Theory the helium condensed into droplets and
  fell towards the core liberating gravitational
  energy
• Calculations seem to support this

14
Saturns Interior

• Saturn is also the most oblate planet
• The density is low due to a much smaller liquid
  metallic hydrogen mantle
• Saturn has a magnetosphere but it is not as
  strong as Jupiters
• Due to slower rotation, less liquid hydrogen and
  blocking of charged particles by the rings

15
Internal Structure of Jupiter and Saturn
16
HST Views the Rings Edge-On
17
Rings and Tides

• This is the region where the tidal force pulling
  the material apart is stronger than the
  gravitational force holding it together

18
Structure of the Rings

• Rings are separated by gaps or divisions with
  relatively few particles
• The size and composition of particles vary from
  ring to ring
• F ring has many small, dark particles

19
Diagram of Saturns Rings
20
Moons and the Rings

• Several moons have orbits within the rings
• Moons may also be a source of ring material
• Examples of moons effecting the rings
• The Encke gap has a small moon, Pan, in it

21
Next Time

• Read Chapter 13.1-13.6

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Summary

• Saturn is the second largest planet and the
  second closest gas giant to Earth
• Saturn is similar to Jupiter with key exceptions
  mostly due to less mass and smaller gravity
• cloud layers are more spread out in depth
• less distinct cloud bands
• larger core
• less liquid metallic hydrogen

23
Summary Rings

• Made up of many distinct rings and ringlets
• Composed mostly of icy particles of various sizes
  and reflectivity
• Ring structure shaped by moons
• Rings cannot form a larger body due to tidal
  forces