ESS 298: OUTER SOLAR SYSTEM. Francis Nimmo. Io against Jupiter, Hubble image, July 1997. Giant Planets. Interiors Composition and phase diagrams Gravimetry / interior structure Heating and energy budget Magnetic fields Formation Rings Atmospheres Structure Dynamics
Io against Jupiter,
Data from Lodders and Fegley 1998. Surface temperature Ts and radius R are measured at 1 bar level. Magnetic moment is given in 10-4 Tesla x R3.
(Lodders and Fegley 1998)
Here P is pressure, r is density, R is gas constant (8.3 J mol-1 K-1), T is temperature, m is the mass of one mole of the gas, g is a constant (ratio of specific heats, ~ 3/2)
(Here T0,P0 are reference temp. and pressure, and c is constant defined on previous slide)
This is an example of adiabatic temperature and density profiles for the upper portion of Jupiter, using the same values as above, keeping g constant and assuming g=1.5
Note that density increases more rapidly than temperature – why?
Slope determined by g
Hydrogen undergoes a phase change at ~100 GPa to metallic hydrogen (conductive)
It is also theorized that He may be insoluble in metallic H. This has implications for Saturn.
Interior temperatures are adiabats
in New Solar System (1999)
All units in W/m2
SaturnEnergy budget observations
Where does this come from?
e.g.Jupiter is radiating 3.5x1017 W in excess of incident solar radiation.
This implies it is contracting at a rate of 0.4 km / million years
Galileo image of Jupiter’s rings
Starlight being occulted by rings;
drop in intensity gives information on particle number density
Cassini colour-coded UV image; blue indicates more water ice present. Note the sharp compositional variations
Main ringsRing Lifetimes
Hubble image of Saturn’s E-ring. Ring
is densest and thinnest at Enceladus, and becomes more diffuse further away. This is circumstantial evidence for Enceladus being the source of the ring material. It is also evidence for Enceladus being active.
Pan opening the Encke division in Saturn’s rings
Pandora and Prometheus shepherding Saturn’s F ring
Waves arising from 5:3 resonance with Mimas. The light and dark patterns are due to vertical oscillations in ring height (right-hand structure) and variations in particle density (left-hand structure)
Thursday’s lecture will be given by Ashwin Vasavada (JPL)
Next week will be the start of the computer project
Here R is the gas constant, mm is the mass of one mole, and RT/gmm is the scale height of the atmosphere (~10 km) which tells you how rapidly pressure increases with depth
Theoretical cloud distribution
CH4 (U,N only)
q is latitude
is a measure of its importance
e.g. Jupiter v~100 m/s, L~10,000km we get ~35 so important