Upload
others
View
1
Download
0
Embed Size (px)
Citation preview
Jupiter and Saturn; Jupiter and Saturn; What we know, How we study them,What we know, How we study them,
and What we and What we stillstill dondon’’t knowt know
Kunio M. Sayanagi (UCLA)
OutlineOutline
1. Giant Planets of our Solar System
2. Jupiter Mission Milestones
3. Cassini at Saturn
Solar System Overview
Vital StatsVital Stats
16h6min
17.143.88164.7930.44Neptune
17h14min
14.544.084.2320.08Uranus
95.18
317.94
1.00
Mass (Earth = 1)
10h14min
9h50min
24h
Rotation Period
1.001.001.0Earth
9.4529.469.54Saturn
11.2111.895.20Jupiter
Radius (Earth = 1)
Orbital Period (Earth-yr)
Distance from Sun
(AU)
Planet
SaturnSaturn’’s Love Handless Love Handles
Vertical Atmospheric StructureVertical Atmospheric Structure
Jupiter Saturn
Giant Planet Giant Planet JetstreamsJetstreams
Beebe. (2005) Fig. 1
Interior StructureInterior Structure
?
• Presence of Rocky Core- Unknown!- Hydrogen Eq. State
• Bulk Composition-- mostly Hydrogen and Helium-- Noble Gas Isotope abundance
will reveal formation history
Gas GiantsIce Giants
Magnetic Fields of Giant PlanetsMagnetic Fields of Giant Planets
?
• Jupiter and Saturn-- Generated in Metal-H Layer-- Strongly Dipolar
• Uranus and Neptune-- Generated in Water+Ice Layer-- Messy Field
How do we study Giant Planets?How do we study Giant Planets?
-- Observations (Earth and SpaceObservations (Earth and Space--Based Telescopes)Based Telescopes)
-- Space ProbesSpace Probes
-- Computer ModelingComputer Modeling
History of Jupiter ExplorationHistory of Jupiter Exploration
Hooke (1665)
Pioneer: ClosePioneer: Close--up Imagesup ImagesPioneer 10 Image of Jupiter in 1973
Voyager: WindsVoyager: WindsVoyager 1 Approach Movie (1979)
Ulysses: MagnetosphereUlysses: Magnetosphere
Galileo: HiGalileo: Hi--Res Wind FieldsRes Wind FieldsGalileo Wind Field Measurement of GRS (Choi et al. 2007)
Galileo: LightningGalileo: LightningGalileo Observation of Lightning Flashes (Little et al. 1999)
Cloud Composition & Vertical StructuresCloud Composition & Vertical StructuresGalileo NIMS Observation of Fresh Ammonia Ice Clouds (Baines et al. 2002)
AuroraAuroraGalileo Observation of Northern Aurora (Ingersoll et al. 1998)
Cassini: Stable Zonal JetsCassini: Stable Zonal Jets
Right:Red = Voyager in 1979 (Limaye, 1986), Black = Cassini in 2000 (Porco, et al. 2003)
Vertical Shear, Eddy Momentum FluxVertical Shear, Eddy Momentum Flux
Vertical Shear (Li et al. 2006)Eddy Momentum Flux (Salyk et al. 2007)
Vortex Life CycleVortex Life Cycle
(Li et al. 2004)
Oval BA Oval BA ““Red Spot Red Spot JrJr””
New HorizonsNew HorizonsNew Horizons Wind Field Measurement of Oval BA (Hueso et al. 2009)
Jupiter & Saturn: What & HowJupiter & Saturn: What & How
- Jupiter and Saturn have:- 3 kinds of clouds (H2O, NH3, NH4SH)- Banded Clouds Jetstreams- Jetstreams are very stable (and we don’t know why)- Long Lived Vortices- Aurora and Magnetospheric Dynamics
- How We Study:- Space Missions- Jets are measured by observing cloud motions- Cloud Composition = Spectroscopy
Near Future MissionsNear Future Missions
1. Juno
2. Europa Jupiter System Mission- Jupiter Europa Orbiter (NASA)- Jupiter Ganymede Orbiter (ESA)- Jupiter Magnetospheric Orbiter (JAXA)?
JunoJuno
- Polar Orbiter- Gravity Measurements to study Interior- IR+Microwave Radiometer to find Water
Limited Imaging Science Capability
View from Europa Jupiter Orbiter
Science Example I: Climate Database• Observing Jupiter from an Orbiter enables
measurements of:– Cloud changes (NH3 ice, H2O ice).– Thermal Structure/Changes.– Jetstreams.– Lightning.
• Constantly evolving dynamic atmosphere:
• Search for relationships between changes.
GRS 1992-1999
II: Waves, Periodicity & Coupling
Reuter et al., (2007)
Friedson et al., 1999Friedson et al., 1999
III: Polar Processes
• Aurora• High-Latitude Jets and Vortices
JupiterJupiter’’s Poles: Unexplored Frontiers Poles: Unexplored Frontier
North Pole South Pole
JupiterJupiter’’s Poles: Unexplored Frontiers Poles: Unexplored Frontier
North Pole South Pole
Sun et al. (unpublished ISS Data)
Polar Waves of JupiterPolar Waves of Jupiter
Polar Hood in UVVincent et al (2000)
Polar Wave in UV – Near IRBarrado-Izagirre (2008)
Polar HighPolar High--Altitude SpotsAltitude Spots
UV Dark Spothttp://photojournal.jpl.nasa.gov/catalog/PIA03473
Orton (personal communication)
Orton (personal communication)
Blue Circle = Persistent Auroral Zone
While Circle = 60degN
Polar TurbulencePolar Turbulence
Three Dynamic RegimesThree Dynamic Regimes
• Equatorial Jet
• Mid-Latitude Mixed Jets + Vortices
• Polar Turbulence
LowLow--lat Jets lat Jets Polar TurbulencePolar Turbulence
Low-Latitude Condition High-Latitude Condition
Sayanagi et al (2008)
- Jetstreams- Why are they stable?- What drives them?- How deep do they reach?
- Polar Turbulence- What process separates the Jets region and Polar
Turbulence?
- Waves- What excites the waves?
- Auroras - Effects on Atmosphere
UnknownsUnknowns
Take Home MessageTake Home Message- Jupiter and Saturn have:
- 3 kinds of clouds (H2O, NH3, NH4SH)- Banded Clouds Jets- Jets are measured thru moving Clouds- Long Lived Vortices- Aurora and Magnetospheric Dynamics
- Unknowns- Jets; Why Stable, How Deep, What drives them- Jets vs. Turbulence- Internal Structure (rocky core?)- Auroras’ effects
- History of Space Missions- Changes in Clouds and Winds Detected- Vertical Thermal and Dynamic Structure- Support Future Planetary Missions (please )