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Evdokimova N., Korablev O., Marchenkov K., Rodin A ., Malova H., Podzolko M., Zelenyi L. Space Research Inst

All images credit: NASA / JPL / Brown University. Evdokimova N., Korablev O., Marchenkov K., Rodin A ., Malova H., Podzolko M., Zelenyi L. Space Research Institute(IKI), Moscow, Russia. Jupiter system. Jupiter has ~50 satellites!.

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Evdokimova N., Korablev O., Marchenkov K., Rodin A ., Malova H., Podzolko M., Zelenyi L. Space Research Inst

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  1. All images credit: NASA / JPL / Brown University Evdokimova N., Korablev O., Marchenkov K., Rodin A., Malova H., Podzolko M., ZelenyiL. Space Research Institute(IKI), Moscow, Russia

  2. Jupiter system Jupiter has ~50 satellites! 1. Io 2. Europa3. Ganymede 4. Callisto 5. Amalthea6. Himalia7. Elara8. Pasiphae 9. Sinope10. Lysithea11. Carme12. Ananke13. Leda 14. Thebe 15. Adrastea16. Metis17. Callirrhoe18. Themisto19. Megaclite20. Taygete21. Chaldene22. Harpalyke23. Kalyke24. Iocaste25. Erinome 26. Isonoe27. Praxidike28. Autonoe29. Thyone30. Hermippe31. Aitne32. Eurydome33. Euanthe34. Euporie35. Orthosie36. Sponde37. Kale 38. Pasithee39. Hegemone40. Mneme41. Aoede42. Thelxinoe43. Arche44. Kallichore45. Helike46. Carpo47. Eukelade48. Cyllene49. Kore50. Herse Ио Каллисто http://physics.fortlewis.edu/Astronomy

  3. Galilean Satellites of Jupiter Four Galilean satellites – since 1610 Jupiter has ~50 satellites! MGS view. Image credit: NASA / JPL Ио 1:2:4 Laplace resonance Io Europa http://physics.fortlewis.edu/Astronomy Ganymede Callisto http://physics.fortlewis.edu/Astronomy

  4. Activity of Galilean satellites Io Europa Ganymede Callisto Magmatism Tectonism Impact cratering Adapted from Bagenal et al., 2004 Tidal Energy Distance from Jupiter. Proportions are not kept

  5. Ganymede: General information • Diameter: D(Gan) = 5262,4 km ~ 1.5D(Moon) ~ 1.08D(Mercury) - the largest (not the heaviest!) satellite of Solar System; • Mass: M(Gan) ~1.48*1023 kg ~ 2M(Moon) • Density: ρ (Gan) ~ 1800-1900 kg/m3 • Orbital parameters: Orbital period: T(Gan) = 7.1546 T(Earth) ~ 7.1546 days Semi-major axis: a = 1 070 412 km Eccentricity: e = 0.0011 (range: 0.0009 ÷ 0.0022) Inclination: i=0,204° (range: 0,05° ÷ 0.32°) Image credit: NASA / JPL Image credit: NASA / JPL

  6. Breakthrough missions having explored Ganymede 1977 – launch Voyager -1 and -2 1989-2003 – Galileo mission. 1996-1997 – the best observation of Ganymde 2006 – launch New Horizons. Now it is going to Pluto. 2007 - Ganymede flyby

  7. Galileo mission (1989-2003) Image credit: NASA / JPL Date: 3 Aug 1989 Image credit: NASA / JPL Date: 18 Oct 1989

  8. Galileo mission (1989-2003) Image credit: NASA / JPL Date: 3 Aug 1989 Image credit: NASA / JPL Date: 18 Oct 1989

  9. Galileo mission (1989-2003) • Spacecraft instruments: • Solid State Imaging Camera (SSI) • Near Infrared Mapping Spectrometer (NIMS) • Photopolarimeter-Radiometer (PPR) • UltraViolet Spectrometer (UVS) • Magnetometer • Energetic particles detector • Plasma wave spectrometer • Dust detector • Heavy ion counter • Atmospheric probe: • Helium abundance detector • Atmospheric structure instrument • Neutral mass spectrometer • Nephelometer • Net flux radiometer • Lightning and radio emission detector Galileo’s look at Ganymede (1996-1997) the highest spatial resolution ( ~12 m/px); the closest flyby ( ~264 km to surface)

  10. Ganymede: previous results Measurement types Problem • Internal structure • Geology, surface morphology • Atmosphere, exosphere • Magnetosphere Gravity field measurements (Galileo) Surface features analysis(from images: Voyager, Galileo), mineral composition (from spectroscopy, Earth-based radar) UV spectroscopic measurments, Voyager-1, HST, Galileo Magnetic field measurements, energetic particles(Galileo), aurorae(HST)

  11. 1. Internal structure Strongly differentiated internal structure: 1) Liquid core : Fe, (+FeS?), R~400-1300 km 2) Rock mantle(silicates, Mg-rich?) 3) Ice mantle (liquid-solid: high-pressure phase), 800-950 km 4) Ice crust (130-150km) (more lighter) Ice phase state and lattice type are unknown… 1 2 3 4 rocks ~60%, ices~40% (if ρ~1,94 g/cm – Pioneer, Voyager) Ice near its melting becomes a low-viscosity solid => => Ice mantle convection like Earth rock mantle?

  12. 1. Internal structure Crust deformations: tides Callisto tidal flexing < Ganymede tidal flexing < Europe tidal flexing Tides from interior model of Ganymede: In the presence of a liquid ocean: tide can exceed 7 m peak-to-peak variation Without an ocean: tidal amplitudes are less than 0.5 m (Moore, 2003) Mass anomalies 2 surface mass anomalies? one a positive mass at high latitude and the other - a negative mass at low latitude. No obvious geological features that can be identified with the anomalies. (Galileo data, Anderson 2004)

  13. 1. Internal structure Open questions Possible solutions and related payload • Interiors structure • Existence of liquid mantle • Origins of mass anomalies • Ice structure and form • Role of tidal heating at present • and in the past • Etc… -Seismometer -Thermal mapping -Gravity field mesurements -Librations measurements (e.g. by stellar sensor) -Etc?…

  14. 2. Geology, surface morphology • Numerous traces of active geological processes in early history: • tectonism, volcanism (caldera-like features- Spaun,2001; • cryovolcanism–Schenk, 2001), etc… • Numerous impact craters • 2 different types of surface: 1 - Dark terrain ~ 1/3 of Ganymede The oldest (~4Gy); heavily cratered; palimpsets; Callisto-like Galileo, 140m/px 2 - Bright terrain(2) ~ 2/3 of Ganymede The youngest; less cratered; lanes through dark terrain *both types may be reticulate

  15. 2. Geology, surface morphology • Numerous traces of active geological processes in early history: • tectonism, volcanism (caldera-like features- Spaun,2001; • cryovolcanism–Schenk, 2001), etc… • Numerous impact craters • 2 different types of surface: DEM of topography (same scene) Galileo, 140m/px *both types may be reticulate Schenk, 2001

  16. Global map based only on low resolution images 2. Geology, surface morphology Galileo/Voyadger data

  17. Morphology map based on Galileo mosaic Geological units Prockter, 1998 Prockter, 1998

  18. 2. Geology, surface morphology • Surficalrocks chemical composition • (telescopic observations; Galileo/NIMS spectroscopic data: T.McCord, 1998, etc) • - mainly H2O ice (50-90%) • presence of CO2 ice (Hibbits, 2003) • signs of SO2 , NH3 • - hydrated minerals (MgSO4·nH2O, Na2Mg(SO4)2·4H2O , ...? • - still under studies • - unknown spectral features • *adsorb. bands 3.7, 3.88, 4.05, 4.25 µm, etc • - unknownmateral: • *darker and redder then water ice: • carbon-rich meteorite/mix of clays/organics component? tholin? • - still under studies…

  19. 2. Geology, surface morphology • Surficalrocks chemical composition • (telescopic observations; Galileo/NIMS spectroscopic data: T.McCord, 1998, etc) • - mainly H2O ice (50-90%) • presence of CO2 ice (Hibbits, 2003), O2 • signs of SO2 , NH3 • - hydrated minerals (MgSO4·nH2O, Na2Mg(SO4)2·4H2O , ...? • - still under studies • - unknown spectral features • *adsorb. bands 3.7, 3.88, 4.05, 4.25 µm, etc • - unknownmateral: • *darker and redder then water ice: • carbon-rich meteorite/mix of clays/organics component? tholin? • - still under studies… NIMS/Galileo mapping Carlson et al., 1996.

  20. 2. Geology, surface morphology Surface temperature distribution (PPR/Galileo data) Day side Night side Heat radiation ~ 60 µm Tmin=80 K (observed) Need for further studies of surficalthermophysical properties!

  21. 2. Geology, surface morphology Possible solutions and related payload Open questions • Searching for specific substances: • -non-organic components: • sulfates, hydrated minerals • -organics: tholin, etc; • Altimetry and geologic mapping; • Thermal inertia data; • (Water) ice microstructure; • Geological processes: current and past • Confirmation of cryovolcanism hypotheses • Age of “dark” and “light” terrains • Vertical structure of crust beneath dark terrain • …. etc • Elemental analysis: • -Laser-stimulated emission UV spectroscopy • -Laser-stimulated mass spectroscopy • Analysis of species: • -IR imaging spectroscopy • -GCMS • -Raman spectroscopy • -DLS spectroscopy • Mineralogical & morphological analysis: • -Multispectral camera • -IR imaging spectroscopy • -Microscope • …etc?

  22. 3. Atmosphere. Exosphere Ganymede does have atmosphere! • Very tenuous one: ~1016 cm-2 • O, O2, H, H2, H2O, OH, … ? • sublimation and sputtering from icy surface ? • Frozen and trapped gases in the Ganymede surface? • -Micron-sized dust halo loosely bound by gravity – ice grains, the result of meteorite impacts

  23. 3. Atmosphere. Exosphere Results of Dust detector/Galileo Kruger, 2000

  24. 3. Atmosphere. Exosphere Possible solutions and related payload Open questions • Abundance of volatiles, isotopes • Sources/sinks, • interactions with the surface and interiors • Exosphere, escape mechanisms • Photochemistry • Interactions with Jovian magnetosphere • Thermal and non-thermal heating, kinetics, • dynamics (tides?) • Dust particles acceleration and escape Mass-spectrometry Radio occultations between the orbiter and lander Microwave sounding from the orbiter IR heterodyne sounding from the orbiter or lander

  25. 4. Magnetosphere

  26. M Ganymede’s magnetic field = internal +induced magnetic fields Magnetic moment M=1,3×1013 Т·м3~ three times greater than Mercury’s magnetic moment The origin of internal m.f. is the dynamo mechanism dueto convection of core forming liquid materials in Ganymede’s core (Fe- FeS ) Hauck et al., JGR, 2006 Ganymede’s magnetic field at equator ~ 720 nT Jupiter’s magnetic field ~120 nT Induced magnetic field ~ 60 nT Region of unstably trapped plasma particles; convection region. Kivelson et al., JGR, 1998 Induced magnetic field is due to time varying component of the externally imposed Jupiter’s magnetic field. Source: electricalconductivity of aliquidwaterlayerbearingelectrolytessuchassaltsandacids. Kivelson et al., Icarus, 2002 Ganymede is surrounded by a corona of hot oxygen atomes Eviator et al., PSS, 2001 L~4-5 RG ~10000-13000 km

  27. Ganymede’s interaction with the Jupiterian magnetosphere 4. Magnetosphere Ganymede’s magnetosphere From presentation by D.Titov

  28. Interaction with Jupiter’s magnetic field Open field lines are connected to Jupiter’s polar magnetic field. Field-aligned currents in Alfven wings ~ 1.2*106A Jia et al., JGR, 2009 Z X Upstream Reconnection line Ionosphere Downstream reconnection line Asymmetrical Magnetopause Ultraviolet auroral brightness (Eviator et al., 2001) Regions of high-energy ions+electrons E~100 keV 4. Magnetosphere Alfven wings Plasma flows. Magnetsopheric convection. No bow shock: velocity of magnetospheric flow is sub-sonic Kivelson et al., 2001 Alfven wings

  29. Amalthea Amalthea Io Io Europa Europa Ganymede Ganymede Charged particle flux and radiation dose equatorial profiles at Jupiter Equatorial profiles of radiation doses under 0.27, 1, 2.2 and 5 g/cm2shielding, and separately dose under 2.2 g/cm2 from protons only near Jupiter. Equatorial profiles of the integral fluxes of E > 0.5, >2 and >10 MeV electrons and E> 2, >10 and >30 MeV protons at Jupiter.

  30. Open questions: 4. Magnetosphere • Sources of internal and induced magnetic fields • Plasma convection and transfer in Ganymede’s magnetosphere • Structure of the ionospheric current system • Particle acceleration mechanisms • Dynamics of heavy ions in polar and equatorial regions; their rolein auroral brightness in Ganymede • Influence of Ganymede to Jupiter’s auroras

  31. Conclusions • Ganymede is exceptionally challenging target • for Russian and international space exploration program • Lots of hot topics to remain hot for the next • 15(?) years • Strong, multidisciplinary community is • needed

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