WELCOME to Aurorae In the Solar System
Aurorae in the Solar System Sponsoring Projects Galileo Europa Mission Jupiter System Data Analysis Program ACRIMSAT Supporting Projects Ulysses Project Outer Planets / Solar Probe NASA HQ Office of Space Science Sun-Earth Connection Theme Stanford Solar Center Deep Space Network SOHO IMIG satellite program Raytheon ITSS Timed Solar2000
Logistics Aurorae in the Solar System Badges - please keep them on & visible Video taping ERC souvenir store - yellow sign (~3:30) Lunch-time activities SFOF - green sign, 11:30 & 12:00 (limit 45/tour) Welcome to Outer Space (video) 11:30-12:00 in Von Karman auditorium Telescopes (weather permitting)
Aurorae in the Solar System Agenda Overview The Solar Maximum apple Light Activities Aurorae on Earth apple Magnetic and Energetic Activities Jupiter s Aurorae and Atmospheric Phenomena The Sun-Jupiter Connection apple Educational Observation Programs Evaluations/Give-Aways/Handouts/Badges +Radio JOVE (depart from blue sign at 3:15)
The Sun How big is it? Overview What s it made of? How is it structured? Aurora What are they? How do they form? Where are they located? The Earth and Jupiter Composition Structure
The Sun Size Mass = 1.99 x 10 30 kg (332,000x Earth) Diameter = 1,392,000 km (109x Earth) Composition abundance mass Hydrogen 91.2% 71.0% Helium 8.6% 27.1 % Oxygen 0.08% 0.97% Carbon 0.045% 0.40 % Nitrogen, Silicon, Magnesium, Neon, Iron, Sulfur 0.03% 0.53%
Measuring Composition Temperature Determined from the peak frequency or wavelength of a continuous spectrum Emission lines Narrow slices of the continuous spectrum Line patterns unique to each element or molecule Absorption lines Gaps in spectrum due to absorption by cool gases Correspond to same wavelengths as emission lines Characteristic of the intervening gas
The Electromagnetic Sky
Spectroscopy Electromagnetic Spectrum Radio waves: sub-cm to 100s m radar, magnetic fields, interstellar gas, galactic structure Infrared radiation: ~1-100 microns molecular composition, cool stars, galaxies visible light: 400-700 nm composition, planets, stars, galaxies Ultraviolet radiation: 10-6 - 10-9 m interstellar medium, hot stars X rays: 10-8 - 10-12 m stellar atmospheres, neutron stars, hot gases Gamma rays: 10-11 - <10-16 m neutron stars, active galactic nuclei
Behind the Scenes Electron Transitions Produce visible & ultraviolet spectral-line features Molecular vibration changes produce infrared spectral features Molecular rotation changes Produce radio-wave spectral-line features
The Sun s Structure thickness (km) density (g/cm 3 ) Core 15 Million K 200,000 150,000 Radiation zone 7 Million K 300,000 15,000 Convection zone 2 Million K 200,000 150 Photosphere 5800 K 500 2x10-4
The Sun s Atmosphere Chromosphere thickness (km) density (g/cm 3 ) 4500 K 1500 5x10-6 Transition Zone 8000 K 8500 2x10-10 Corona 1 Million K millions 10-12 Solar wind 2 Million K 10-23
The Sun s Corona
The Corona and Solar Wind Coronal holes Low-density (by ~10x) regions, 10s to 100s of thousands of km across Magnetic field lines extend far out into space Permit escape of matter, windows for solar wind
The Corona and Solar Wind The Solar Wind Electromagnetic radiation Fast-moving (500 km/sec) charged particles Protons, Electrons Output Transport of ~1 million tons of solar matter / second 4x10 26 Watts (= 100 billion 1-megaton bomb / second) 1400 watts/m 2 reaches Earth
Aurorae in the Solar System Ingredients: Solar wind supplies charged particles Magnetic Field accelerates charged particles Atmosphere excited by charged particles emit photons producing aurora Colors produced by type of atom or molecule excited and path used to return to ground state
Aurorae in the Solar System Mercury? Jupiter Venus Earth Mars Saturn Uranus Pluto Neptune
Aurorae in the Solar System Mercury - no Jupiter Venus? Earth Mars Saturn Uranus Pluto Neptune
Aurorae in the Solar System Mercury - no Jupiter Venus - no. Earth? Mars Saturn Uranus Pluto Neptune
Aurorae in the Solar System Mercury - no Jupiter Venus - no Earth - yes Mars? Saturn Uranus Pluto Neptune
Aurorae in the Solar System Mercury - no Venus - no Earth - yes Mars - no. Jupiter? Io? Europa? Ganymede? Callisto? Saturn Uranus Pluto Neptune
Jovian Aurora
Io Aurora
Aurorae in the Solar System Mercury - no Venus - no Earth - yes Mars - no Jupiter - yes Io - yes Europa -? We re looking Ganymede - yes Callisto - none detected Saturn? Titan? Uranus Pluto Neptune
Saturnian Aurora
Aurorae in the Solar System Mercury - no Venus - no Earth - yes Mars - no Jupiter - yes Io - yes Europa -? We re looking Ganymede - yes Callisto - none detected Saturn - yes Titan - wait for Cassini Uranus? Pluto Neptune
Aurorae in the Solar System Mercury - no Venus - no Earth - yes Mars - no Jupiter - yes Io - yes Europa -? We re looking Ganymede - yes Callisto - none detected Saturn - yes Titan - wait for Cassini Uranus - yes Pluto Neptune?
Aurorae in the Solar System Mercury - no Venus - no Earth - yes Mars - no Jupiter - yes Io - yes Europa -? We re looking Ganymede - yes Callisto - none detected Saturn - yes Titan - wait for Cassini Uranus - yes Pluto -? Neptune - yes
Aurorae in the Solar System Mercury - no Venus - no Earth - yes Mars - no Jupiter - yes Io - yes Europa -? We re looking Ganymede - yes Callisto - none detected Saturn - yes Titan - wait for Cassini Uranus - yes Pluto - probably not Neptune - yes
The Earth Structure Core Inner Outer Mantle Crust Composition Iron, Nickel, Sulfur Solid Liquid Fe-, Mg-rich silicates Silicates, carbonates, etc. Atmosphere N 2, O 2, Ar, CO 2, H 2 O, etc. Magnetosphere Van Allen belts Electrons (outer) Protons (inner)
Visible Aurora Images courtesy Jan Curti s
X-ray Aurora
Jupiter Atmospheric Composition 86.1% H & 13.8% He methane, ammonia, water vapor Atmospheric Structure Gaseous upper atmosphere Liquid mantle High-density core Atmospheric Features Bright zones and dark belts Storms: Great Red Spot, White Ovals, etc. Lightning Auroral activity Magnetosphere
Aurora Occur when atmospheric molecules are excited by incoming charged particles which have accelerated by a magnetosphere Generally occur near high latitudes, near the north and south magneti c poles Charged particles are continually resupplied by the sun *Rates may vary