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Composition and Mineralogy of Nuclei Material of Short Period Comets Revealed by Recent Spacecraft Missions
Engrand, Cecile; Nakamura, Tomoki; Zolensky, Michael +1 more
We summarize mineralogical and compositional results from lab and in-situ spacecraft investigations of samples of comets 81P/Wild 2 and 67P/Churyumov-Gerasimenko which provide constraints to early solar system evolution. Wild 2 cometary solids were mineralogically similar to anhydrous chondritic Interplanetary Dust Particles with the exception tha…
Heavy Molecular and Metallic Ions in the Magnetosphere
Yamauchi, M.; Wurz, P.; Dandouras, I. +11 more
Observations and present knowledge of heavy ions with mass ≥ 27 in the magnetosphere are reviewed. There are four ultimate sources of these heavy ions: the solar wind (mainly high charge-state atomic ions), the ionosphere (mainly molecular ions), the atmospheric metal layers that originate ultimately from ablation of meteoroids and possibly space …
Mars' Water Cycle and Escape: A View from Mars Express and Beyond
Aoki, S.; Villanueva, G. L.; Liuzzi, G. +12 more
The search for water on Mars has long been a theme of intense exploration, as it represents a means of addressing Mars' current climate as well as its evolution in the recent and more distant past. Since the 1970s, several missions have carried instruments to track water in the atmosphere, leading to the conceptualization of a water cycle on Mars …
Composition and Chemistry of the Martian Atmosphere as Observed by Mars Express and ExoMars Trace Gas Orbiter
Montmessin, Franck; Korablev, Oleg; Fedorova, Anna +13 more
The atmosphere of Mars has been studied for many years now by a long series of missions. The paper focuses on the results obtained by two of these that are led by European researchers overseen by the European Space Agency, i.e., Mars Express which was launched in 2003 and ExoMars Trace Gas Orbiter launched in 2016. Both missions are still providin…
Parker Solar Probe: Four Years of Discoveries at Solar Cycle Minimum
McComas, D. J.; Bale, S. D.; Matteini, L. +55 more
Launched on 12 Aug. 2018, NASA's Parker Solar Probe had completed 13 of its scheduled 24 orbits around the Sun by Nov. 2022. The mission's primary science goal is to determine the structure and dynamics of the Sun's coronal magnetic field, understand how the solar corona and wind are heated and accelerated, and determine what processes accelerate …
HelioSwarm: A Multipoint, Multiscale Mission to Characterize Turbulence
Verscharen, Daniel; Retinò, Alessandro; Alexandrova, Olga +47 more
HelioSwarm (HS) is a NASA Medium-Class Explorer mission of the Heliophysics Division designed to explore the dynamic three-dimensional mechanisms controlling the physics of plasma turbulence, a ubiquitous process occurring in the heliosphere and in plasmas throughout the universe. This will be accomplished by making simultaneous measurements at ni…
Herbig Stars
Waters, L. B. F. M.; Brittain, Sean D.; Kamp, Inga +2 more
Herbig Ae/Be stars are young contracting stars on the radiative track in the HR diagram on their way to the main sequence. These stars provide a valuable link between high and low mass stars. Here we review the progress that has been made in our understanding of these fascinating objects and their disks since the last major review on this topic pu…
Venus Evolution Through Time: Key Science Questions, Selected Mission Concepts and Future Investigations
Korablev, Oleg; Marcq, Emmanuel; Hensley, Scott +42 more
In this work we discuss various selected mission concepts addressing Venus evolution through time. More specifically, we address investigations and payload instrument concepts supporting scientific goals and open questions presented in the companion articles of this volume. Also included are their related investigations (observations & modelin…
Dynamics of Large-Scale Solar Flows
Gizon, Laurent; Noraz, Quentin; Hotta, Hideyuki +2 more
The Sun's axisymmetric large-scale flows, differential rotation and meridional circulation, are thought to be maintained by the influence of rotation on the thermal-convective motions in the solar convection zone. These large-scale flows are crucial for maintaining the Sun's global magnetic field. Over the last several decades, our understanding o…
Particle Acceleration by Magnetic Reconnection in Geospace
Khotyaintsev, Yuri; Drake, James F.; Oka, Mitsuo +7 more
Particles are accelerated to very high, non-thermal energies during explosive energy-release phenomena in space, solar, and astrophysical plasma environments. While it has been established that magnetic reconnection plays an important role in the dynamics of Earth's magnetosphere, it remains unclear how magnetic reconnection can further explain pa…