Transcript ppt - Solar Physics and Space Weather

Jupiter and its Moons
Lab 4
Jupiter
• 5th planet from the Sun
• largest one in the solar system
• if Jupiter were hollow, more than one thousand
Earths could fit inside
• contains more matter than all of the other
planets combined
• mass of 1.9 x 1027 kg
• 28 known satellites, 4 of which (Callisto, Europa,
Ganymede and Io) were observed by Galileo in
1610
• there is a ring system, but it is very faint
• Jupiter radiates more energy into space than it
receives from the Sun. Its core is ~ 20,000˚ K.
Mythology associated
• Jupiter (Zeus) was the King of the Gods, the ruler of
Olympus and the patron of the Roman state. Zeus was
the son of Cronus (Saturn).
• Europa is named after the beautiful Phoenician princess
who, according to Greek mythology, Zeus saw gathering
flowers and immediately fell in love with. Zeus
transformed himself into a white bull and carried Europa
away to the island of Crete. He then revealed his true
identity and Europa became the first queen of Crete.
Zeus later re-created the shape of the white bull in the
stars which is now known as the constellation Taurus.
Jupiter
• composed of 90% hydrogen and 10% helium, with small
amounts of CH4, NH3, H2O vapor and other compounds
• At great depths within Jupiter, the pressure is so great
that the hydrogen atoms are broken up, freeing the
electrons so that the resulting atoms consist of bare
protons. This produces a state in which the hydrogen
becomes metallic
• dynamic weather systems illustrated by colorful
latitudinal bands, atmospheric clouds and storms
• cloud patterns change within hours or days
• The Great Red Spot is a complex storm moving in a
counter-clockwise direction. At the outer edge, material
appears to rotate in four to six days; near the center,
motions are small and nearly random in direction
Jupiter animation
• http://www.solarviews.com/raw/jup/vjupitr5
.mpg
Internal Structure of Jupiter
• The outer layer is primarily composed of molecular
hydrogen
• At greater depths the hydrogen starts resembling a liquid
• At 10,000 kilometers below Jupiter's cloud top liquid
hydrogen reaches a pressure of 1,000,000 bar with a
temperature of 6,000° K.
• At this state hydrogen changes into a phase of liquid
metallic hydrogen. In this state, the hydrogen atoms
break down yielding ionized protons and electrons
similar to the Sun's interior.
• Below this is a layer dominated by ice where "ice"
denotes a soupy liquid mixture of water, methane, and
ammonia under high temperatures and pressures
• Finally at the center is a rocky or rocky-ice core of up to
10 Earth masses
The Galilean Moons
Ganymede
• largest moon of Jupiter and is the largest in our
solar system with a diameter of 5,262 km (3,280
miles)
• composed of a rocky core with a water/ice
mantle and a crust of rock and ice
• no known atmosphere, but presence of ozone
means a thin tenuous oxygen atmosphere from
charged particles disrupting surface ice
• http://www.solarviews.com/raw/jup/vgany2.mpg
Callisto
• 2nd largest moon of Jupiter, 3rd largest in the solar
system, ~same size as Mercury
• orbits just beyond Jupiter's main radiation belt
• Callisto is the most heavily cratered satellite in the solar
system
• Its crust is very ancient and dates back 4x109 years
• Callisto has the lowest density (1.86 gm/cm3) of the
Galilean
• appears to be composed of a crust 200 km thick
• Beneath the crust is a possible salty ocean ~10 km thick
• Beneath the ocean, is an unusual interior composed of
compressed rock and ice with the percentage of rock
increasing as depth increases
• Callisto, like Ganymede, has no known atmosphere
Callisto animation
• http://www.solarviews.com/raw/jup/vcallis1
.mpg
Europa
• crust composed of water and ice
• surface is among the brightest and smoothest in
the solar system
• Lines and cracks wrap the exterior as if a child
had scribbled around it.
• Europa may be internally active, and its crust
may have, or had in the past, liquid water which
can harbor life
• http://www.solarviews.com/raw/jup/veuropa1.mp
g
Io
• most volcanic body known, with lava flows, lava
lakes, and giant calderas covering its sulfurous
landscape
• billowing volcanic geysers spewing sulfurous
plumes 500 km high
• Its mountains are much taller than those on
Earth reaching heights of 16 km (52,000 feet)
• Io appears to be a rocky silicate rich body that
has a dense Fe/FeS core that extends halfway
to the surface with a partially melted silicate-rich
mantle, and a thin rocky crust.
• http://www.solarviews.com/raw/jup/vio1.mpg
Internal Structure of Io
Very Exotic
• Io orbits very close to Jupiter's cloud tops, placing it
within an intense radiation belt that bathes the satellite
with energetic electrons, protons, and heavier ions
• As the Jovian magnetosphere rotates, it sweeps past Io
and strips away ~1,000 kg (1 ton)/sec of volcanic gases
• This produces a neutral cloud of atoms orbiting with Io
as well as a huge, doughnut shaped torus of ions that
glow in the ultraviolet.
• Io acts as an electrical generator as it moves through
Jupiter's magnetic field, developing 400,000 volts across
its diameter and generating an electric current of 3x106
amperes that flows along the magnetic field to the
planet's ionosphere
Using Kepler’s 3rd Law
• MJupiter = a3/P2
where M=mass of Jupiter in solar
masses, a=radius of its moon’s
orbit in AU, and P=period of its
moon’s orbit in years
Converting to Keplerian Units
• If P=5 days, then 5/365 = 0.014 years
• If a = 3.5 JD, where JD is diameter of
Jupiter,
then 3.5JD/(1050JD/AU)=0.0033AU