JUNO: sopravvivere alle radiazioni · Alberto Adriani INAF Istituto di Fisica dello Spazio Interplanetario Roma. Science Goals are aimed at understanding both our own solar system

JUNO:sopravvivere alle

radiazioni

Alberto AdrianiINAF

Istituto di Fisica dello Spazio InterplanetarioRoma

Science Goals are aimed at understanding both our own solar system and extra-solar planetary systems

The Formation of Jupiter

Jupiter is our archetype for extra-solar giant planet formation and evolution theory.

The abundances of oxygen and nitrogen are key to understanding how giant planets formed.

Competing theories on the formation of Jupiter do not agree on temperature, birthplace, composition, and proportion of icy planetesimals that led to Jupiter’s formation.

Theories also have different predictions for core sizes and total amount of heavy elements in present day Jupiter.

The Evolution of Jupiter

Improving our understanding of Jupiter evolution will allow more accurate determination of the composition of extra-solar planets…with direct consequences for formation theories of planetary systems.

Current evolution models are very uncertain due to a lack of data on the possible presence of a radiative zone, the amount of heavy elements present in Jupiter, and the structure of its molecular envelope.

Models of Jupiter’s interior lack observational constraints to pinpoint the planets central core mass and global composition.

Key Questions

o How did the giant planets form?

o Does Jupiter have a rock-ice core, and if so how large is it?

o How different is the composition of Jupiter from the original solar nebula, and if it's different, what is the cause?

o How deep into the atmosphere do the Great Red Spot and other atmospheric features reach?

o How does the dynamo on Jupiter work?

Key Questions

o How did the giant planets form?

o Does Jupiter have a rock-ice core, and if so how large is it?

o How different is the composition of Jupiter from the original solar nebula, and if it's different, what is the cause?

o How deep into the atmosphere do the Great Red Spot and other atmospheric features reach?

o How does the dynamo on Jupiter work?

JUNO Measurement Objectives Summary(1/2)

• X and Ka band doppler radio measurements –High order gravity zonal harmonicsIntegrated radio science/telecomm (gravimeter)

• Scalar and vector measurements of magnetic field–Magnetic field spherical harmonics and mapsMagnetometer

• Radio brightness temperatures between 1 and 100 cm at all latitudes, infrared emission, and solar reflection–Global water and ammonia abundancesRadiometer, Image Spectrometer–Zone/belt variability at pressures up to 1000 barsRadiometer

• Particles, waves and field measurements in polar magnetosphere (fluxes, pitch angle, composition, wave power).–Sources of aurora, exploration of Jovian polar magnetosphere–Particle acceleration mechanisms associated with aurora and Io footprint.Energetic Particle Spectrometer, plasma sensor, plasma wave detector

• Remote sensing of aurora and Jovian atmosphere in UV & IR.–Time variability and morphology of Jovian auroraIR image spectrometer, UV spectrometer

JUNO Measurement Objectives Summary(2/2)

Mission Description (1)

• Launch: August 2011• 32 Jupiter orbits, 11 days per orbit• X and Ka band (up and down) telecom/

gravity science subsystem• 2 rpm spin• High inclination (80º-90º),

low perijove (1.06 RJ), 11 day Jupiter orbit (~39 RJ apojove)

• Dual mode (bi-prop) propulsionsubsystem (1700 m/s direct, 2000 m/s ∆V-EGA)

• Magnetically “clean” orbiter• Design to 375 krad (behind 100 mils

Aluminum), RDM of 2 (750 krads)

Mission Description (2)

The Italian Contribution to JUNOJIRAM, the Jovian InfraRed Auroral Mapper

Mirror

Heritage: Cassini-VIMS, Rosetta-VIRTIS, VEX-VIRTIS, Dawn-VIR.New Challenges: Spinning SpacecraftPassive Cooling Harsh EnvironmentNew Detection Concept New In-Flight CalibrationVery High Vibrations Limited Mass AllowanceLimited Power AllowanceLimited Data Volume Limited Developing Time

H3+ emissions measured byCassini-VIMS

H3+ emissions

SCIENTIFIC OBJECTIVE 1: Auroral Region

SCIENTIFIC OBJECTIVE 2: Hot Spots

Hot spots seen by Galileo-NIMS

Simulations for JIRAM

H2O

NH3

SCIENTIFIC OBJECTIVE 3: Troposphere Sounding

Credit: Imke de Pater, Michael Wong (UC Berkeley); Al Conrad (Keck), and Chris Go (Cebu, Philippines)

Atreya et al., 2005

by Cassini VIMS

by Cassini VIMS

Saturn

Jupiter

Conclusions

JIRAM is the missing ring of the Juno mission