Reports on improvement in general circulation models of the thermosphere and lower atmospheres of the planets and descriptions of future planetary missions are also invited. Deadline for abstract submission: 15 March but seems still on [March 21]. This includes new ground-based, air- and spaceborne instrument developments, development proposals and related topics i. Conveners: - Dr.
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The solar system contains a variety of planetary bodies, which present unique and interesting combinations of atmospheres, ionospheres, and magnetospheres. These spheres are connected to solar wind on one end and surface on the other, thus providing a complex coupling between the surface-neutral-plasma systems. Studying them in comparative manner enhances our thinking and knowledge about processes and physical phenomena occurring in these regions.
This symposium will address observational, theoretical and modeling studies pertaining to physical, chemical, and dynamical processes occurring in atmospheres, ionospheres, and magnetospheres of planets, moons, and comets as well as their coupling among themselves and with solar wind. Studies on energetic neutral atoms ENA will also be addressed in this session.
The session will encourage presentations that use comparative approach to a phenomena occurring in different planetary environments and will include both invited and contributed presentations. Innovative experimental techniques and ideas for missions to study surface-atmosphere-magnetosphere systems on planetary bodies will also be welcome.
Therese Encrenaz Observatoire de Paris. This session will address the latest results of the different ongoing missions in orbit around Venus and Mars as well as on the surface of Mars. It will cover all fields of research from the ionosphere, the atmosphere to the surface and planetary interior. Venus Express finally is exploring Venus from orbit. All these missions are extending and modifying our understanding of the two planets substantially. The session is primarily targeted. The second objective of the session is to discuss upcoming future mission programs and the results obtained from new ground-based observations.
Broad solicited talks and focused contributed presentations will be highlighted in the program. Jorn Helbert DLR.
This session will enacompass observational, theoretical and numerical studies of the neutral atmospheres of the giant planets, Pluto, Titan, Enceladus, Triton, Io and Europa. The surface of Titan and the surface-atmosphere interactions will be considered. Papers on the results of observations from the earth and spacecraft, their interpretations, and on relevant laboratory measurements are encouraged.
The session will include a mix of solicited, contributed and poster presentations. Athena Coustenis Paris Observatory - Prof. Sushil Atreya Univ. Hauke Hussmann University of Muenster - Prof. Jianping Li Chinese Academy of Sciences. This session aims to provide a forum for the discussion of radio emission in the solar system. Topics include but are not limited to solar and planetary radio emission, radio emission from planetary foreshocks, Earth's magnetospheric and ionospheric radiation phenomena, and radio emission from the outerheliosphere.
Theoretical studies, numerical simulations and laboratory work on radio emission mechanisms, dynamics of particle-wave and wave-wave interactions are all welcome. Relevant observations not covered in other dedicated sessions are also welcome.
Atmospheres in the Solar System by Michael Mendillo, Andrew Nagy | Waterstones
Bo Li University of Sydney - Dr. Peter Yoon University of Maryland. Deadline for online abstract submission: 18 May The session will focus on the observations and theoretical modelling of the atmospheres of solar system gas Jupiter, Saturn and ice giants Neptune, Uranus and will build a bridge to the atmospheres expected on extra-solar planets of these types. Papers on the atmospheres of Venus and Mars, including but not limited to results from Venus Express and Mars Express, are welcome. These may include observations, data analysis, modelling, and associated theoretical and laboratory work.
Submissions on atmospheric processes or frozen volatiles on Mercury, Moon, and minor bodies are also acceptable, as are papers about the existence, detection and properties of terrestrial-type exoplanets. Descriptions of proposed new missions or programmes related to any of the above are encouraged. This session will be scheduled as a Workshop aiming to discuss recent developments in planetary atmospheres : the giant planets, satellites with an atmosphere e. Titan, Enceladus, Europa, etc , as well as Pluto. We will have mainly solicited, a few contributed and poster papers with the focus on observations from the earth and spacecraft, together with papers on theoretical interpretations, results of modelling and pertinent laboratory measurements.
Neutral and ion atmospheres and their relationship to surface, interior and magnetospheres of the outer planetary systems will be emphasized. The workshop format should allow us to have time for discussion. Conveners: - Coustenis, A. Key topics of planetary and solar radio emissions as well as radiation from the heliosphere and from extrasolar planets will be discussed with special emphasis on current missions like Cassini, Voyager, Ulysses, Wind and STEREO, including further analysis of data from older missions such as Galileo.
In addition to space observations and their interpretations, ground-based measurements in the decameter-to-meter wavelength range and new developments on giant radio telescopes e. Presentations should focus on problems like the modulation by planetary spin, highly structured features in dynamic spectra, their connection to plasma and magnetic processes, and other topics including theoretical modeling, simulations, and comparative studies.
Key questions for potential future missions e. Solar Orbiter, Juno and projects e. Conveners: - Rucker, H. United States of America - Zarka, P. The top of the atmosphere of a planetary body is the conduit through which the escape of gases to space occurs. The strong evidence for liquid water at the surface of Mars in its early history but not today suggests that dramatic climate change has occurred.
Evidence points to loss to space as being a significant force behind this change. Escape of planetary ions in the wake of Mars and Venus via the interaction with the solar wind plasma is one channel for this escape and we have nowadays the unique opportunity to compare them with similar instrumentation on Mars Express and Venus Express.
The session will also be devoted to new results from Cassini around Saturn's moons including Titan, Enceladus, Rhea and others, as well as theoretical studies or numerical simulation works. Paper relating to other space missions or future projects are also welcome. Observations combined with theory and numerical modeling of these interactions will lead to better understanding of these various processes and will give directions for future missions to e. We would like to invite both observational and theoretical presentations. Conveners: - Volwerk, M.
Comparative Aeronomy in the Solar System Meetings:. This session will focus on two complementary aspects of planetary magnetism: 1 Interpretation of magnetic anomalies measured around the Moon, planets and asteroids. Convener : - J.
The session is primarily targeted at presentations of new measurements, but authors presenting papers on theory and modelling in support of the analysis of new results will be most welcome. Conveners: - Rauer, H. Conveners: - Taylor, F. Poldervaart focused on the Moon, stating "An adequate picture of this original planet and its development to the present earth is of great significance, is in fact the ultimate goal of geology as the science leading to knowledge and understanding of earth's history.
All terrestrial planets and some satellites, such as the Moon are essentially composed of silicates wrapped around iron cores. Volcanism on Earth is largely lava -based. Other terrestrial planets display volcanic features assumed to be lava-based, evaluated in the context of analogues readily studied on Earth.
For example, Jupiter's moon Io displays extant volcanism , including lava flows. These flows were initially inferred to be composed mostly of various forms of molten elemental sulfur , based on analysis of imaging done by the Voyager probes. Much of the surface of Mars is composed of various basalts considered analogous to Hawaiian basalts, by their spectra and in situ chemical analyses including Martian meteorites.
Surfaces in the polar regions show polygonal morphologies , also seen on Earth. In addition to basalt flows, Venus is home to a large number of pancake dome volcanoes created by highly viscous silica-rich lava flows. These domes lack a known Earth analogue. They do bear some morphological resemblance to terrestrial rhyolite-dacite lava domes , although the pancake domes are much flatter and uniformly round in nature.
Certain regions further out in the Solar System exhibit cryovolcanism , a process not seen anywhere on earth. Cryovolcanism is studied through laboratory experiments, conceptual and numerical modeling, and by cross-comparison to other examples in the field.
Examples of bodies with cryovolcanic features include comets , some asteroids and Centaurs , Mars , Europa , Enceladus , Triton , and possibly Titan , Ceres , Pluto , and Eris. The trace dopants of Europa's ice are currently postulated to contain sulfur. Assumed to have experienced little or no heating, these materials may contain or be samples representing the early Solar System, which have since been erased from Earth or any other large body. Some extrasolar planets are covered entirely in lava oceans , and some are tidally locked planets, whose star-facing hemisphere is entirely lava.
The craters observed on the Moon were once assumed to be volcanic. Earth, by comparison, did not show a similar crater count, nor a high frequency of large meteor events , which would be expected as two nearby bodies should experience similar impact rates. Eventually this volcanism model was overturned, as numerous Earth craters demonstrated by e.
Craters formed by larger and larger ordnance also served as models. The Moon, on the other hand, shows no atmosphere or hydrosphere, and could thus accumulate and preserve impact craters over billions of years despite a low impact rate at any one time. In addition, more searches by more groups with better equipment highlighted the great number of asteroids, presumed to have been even more numerous in earlier Solar System periods.
As on Earth, a low crater count on other bodies indicates young surfaces. This is particularly credible if nearby regions or bodies show heavier cratering. Young surfaces, in turn, indicate atmospheric, tectonic or volcanic, or hydrological processing on large bodies and comets, or dust redistribution or a relatively recent formation on asteroids i. Examination of the cratering record on multiple bodies, at multiple areas in the Solar System, points to a Late Heavy Bombardment , which in turn gives evidence of the Solar System's early history.
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However, the Late Heavy Bombardment as currently proposed has some issues and is not completely accepted. As a large body, Earth can efficiently retain its internal heat from its initial formation plus decay of its radioisotopes over the long timescale of the Solar System.
It thus retains a molten core , and has differentiated - dense materials have sunk to the core, while light materials float to form a crust. Other bodies, by comparison, may or may not have differentiated, based on their formation history, radioisotope content, further energy input via bombardment, distance from the Sun, size, etc. Studying bodies of various sizes and distances from the Sun provides examples and places constraints on the differentiation process. Differentiation itself is evaluated indirectly, by the mineralogy of a body's surface, versus its expected bulk density and mineralogy, or via shape effects due to slight variations in gravity.
Edge cases include Vesta and some of the larger moons, which show differentiation but are assumed to have since fully solidified. The question of whether Earth's Moon has solidified, or retains some molten layers, has not been definitively answered. Additionally, differentiation processes are expected to vary along a continuum. This continuum is thought to record the varying chemistries of the early Solar System, with refractories surviving in warm regions, and volatiles driven outward by the young Sun.
The cores of planets are inaccessible, studied indirectly by seismometry, gravimetry, and in some cases magnetometry. However, iron and stony-iron meteorites are likely fragments from the cores of parent bodies which have partially or completely differentiated, then shattered.
These meteorites are thus the only means of directly examining deep-interior materials and their processes. Gas giant planets represent another form of differentiation, with multiple fluid layers by density. Some distinguish further between true gas giants, and ice giants further from the Sun. In turn, a molten core may allow plate tectonics, of which Earth shows major features. Mars, as a smaller body than Earth, shows no current tectonic activity, nor mountain ridges from geologically recent activity. This is assumed to be due to an interior that has cooled faster than the Earth see geomagnetism below.
An edge case may be Venus, which does not appear to have extant tectonics. However, in its history, it likely has had tectonic activity but lost it. Io, despite having high volcanism, does not show any tectonic activity, possibly due to sulfur-based magmas with higher temperatures, or simply higher volumetric fluxes.
Europa is a key demonstration of outer-planet tectonics. Its surface shows movement of ice blocks or rafts , strike-slip faults , and possibly diapirs. The question of extant tectonics is far less certain, possibly having been replaced by local cryomagmatism. Earthquakes are well-studied on Earth, as multiple seismometers or large arrays can be used to derive quake waveforms in multiple dimensions. The Moon is the only other body to successfully receive a seismometer array; "marsquakes" and the mars interior are based on simple models and Earth-derived assumptions. Venus has received negligible seismometry.
Gas giants may in turn show different forms of heat transfer and mixing. Uranus shows a net negative heat budget to space, but the others including Neptune, farther out are net positive. Two terrestrial planets Earth and Mercury display magnetospheres, and thus have molten metal layers. Similarly, all four gas giants have magnetospheres, which indicate layers of conductive fluids. Ganymede also shows a weak magnetosphere, taken as evidence of a subsurface layer of salt water, while the volume around Rhea shows symmetrical effects which may be rings or a magnetic phenomenon.
Of these, Earth's magnetosphere is by far the most accessible, including from the surface. It is therefore the most studied, and extraterrestrial magnetospheres are examined in light of prior Earth studies. Still, differences exist between magnetospheres, pointing to areas needing further research. Jupiter's magnetosphere is stronger than the other gas giants, while Earth's is stronger than Mercury's. Mercury and Uranus have offset magnetospheres, which have no satisfactory explanation yet.
Uranus' tipped axis causes its magnetotail to corkscrew behind the planet, with no known analogue. Future Uranian studies may show new magnetospheric phenomena. Mars shows remnants of an earlier, planetary-scale magnetic field, with stripes as on Earth. This is taken as evidence that the planet had a molten metal core in its prior history, allowing both a magnetosphere and tectonic activity as on Earth. Both of these have since dissipated.
Earth's Moon shows localized magnetic fields, indicating some process other than a large, molten metal core. This may be the source of lunar swirls , not seen on Earth. Apart from their distance to the Sun, different bodies show chemical variations indicating their formation and history. Neptune is denser than Uranus, taken as one piece of evidence that the two may have switched places in the early Solar System. Comets show both high volatile content, and grains containing refractory materials. This also indicates some mixing of materials through the Solar System when those comets formed.
Isotopic abundances indicate processes over the history of the Solar System.
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To an extent, all bodies formed from the presolar nebula. Various subsequent processes then alter elemental and isotopic ratios. The gas giants in particular have enough gravity to retain primary atmospheres, taken largely from the presolar nebula, as opposed to the later outgassing and reactions of secondary atmospheres. Differences in gas giant atmospheres compared to solar abundances then indicate some process in that planet's history. Meanwhile, gases at small planets such as Venus and Mars have isotopic differences indicating atmospheric escape processes.
The various modifications of surface minerals, or space weathering , is used to evaluate meteorite and asteroid types and ages. Rocks and metals shielded by atmospheres particularly thick ones , or other minerals, experience less weathering and fewer implantation chemistries and cosmic ray tracks.
Asteroids are currently graded by their spectra, indicating surface properties and mineralogies. Some asteroids appear to have less space weathering, by various processes including a relatively recent formation date or a "freshening" event. As Earth's minerals are well shielded, space weathering is studied via extraterrestrial bodies, and preferably multiple examples. Kuiper Belt Objects display very weathered or in some cases very fresh surfaces.
As the long distances result in low spatial and spectral resolutions, KBO surface chemistries are currently evaluated via analogous moons and asteroids closer to Earth. Earth's atmosphere is far thicker than that of Mars, while far thinner than Venus'. In turn, the envelopes of gas giants are a different class entirely, and show their own gradations.
Meanwhile, smaller bodies show tenuous atmospheres "surface-bound exospheres" , with the exception of Titan and arguably Triton. Comets vary between negligible atmospheres in the outer solar system, and active comas millions of miles across at perihelion. Exoplanets may in turn possess atmospheric properties known and unknown in our star system. Atmospheric escape is largely a thermal process. The atmosphere a body can retain therefore varies from the warmer inner Solar System, to the cooler outer regions.
Different bodies in different Solar System regions provide analogous or contrasting examples. The atmosphere of Titan is considered analogous to an early, colder Earth; the atmosphere of Pluto is considered analogous to an enormous comet.
Free Atmospheres In The Solar System: Comparative Aeronomy
The presence or absence of a magnetic field affects an upper atmosphere, and in turn the overall atmosphere. Impacts of solar wind particles create chemical reactions and ionic species, which may in turn affect magnetospheric phenomena. Earth serves as a counterexample to Venus and Mars, which have no planetary magnetospheres, and to Mercury, with a magnetosphere but negligible atmosphere.
Jupiter's moon Io creates sulfur emissions, and a feature of sulfur and some sodium around that planet. Similarly, Earth's Moon has trace sodium emissions, and a far weaker tail. Mercury also has a trace sodium atmosphere. Jupiter itself is assumed to have some characteristics of extrasolar "super Jupiters" and brown dwarves. Uranus, tipped on its side, is postulated to have seasonal effects far stronger than on Earth. Similarly, Mars is postulated to have varied its axial tilt over eons, and to a far greater extent than on Earth.
This is hypothesized to have dramatically altered not only seasons but climates on Mars, for which some evidence has been observed. From Earth, a planetwide cloud layer is the dominant feature of Venus in the visible spectrum; this is also true of Titan. Venus' cloud layer is composed of sulfur dioxide particles, while Titan's is a mixture of organics. The gas giant planets display clouds or belts of various compositions, including ammonia and methane. Venus and Titan, and to a lesser extent Earth, are superrotators- the atmosphere turns about the planet faster than the surface beneath.
While these atmospheres share physical processes, they exhibit diverse characteristics. Hadley cells , first postulated and confirmed on Earth, are seen in different forms in other atmospheres. Earth has Hadley cells north and south of its equator, leading to additional cells by latitude. Mars' Hadley circulation is offset from its equator. The bands of Jupiter are thought to be numerous Hadley-like cells by latitude. The large storms seen on the gas giants are considered analogous to Earth cyclones. However, this is an imperfect metaphor as expected, due to the large differences in sizes, temperature, and composition between Earth and the gas giants, and even between gas giants.
Polar vortices were observed on Venus and Saturn. In turn, Earth's thinner atmosphere shows weaker polar vorticity and effects. Both lightning and aurorae have been observed on other bodies after extensive study at Earth.
Related Atmospheres in the Solar System: Comparative Aeronomy
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