121 results found
Moore L, Melin H, O'Donoghue J, et al., 2019, Modelling H-3(+) in planetary atmospheres: effects of vertical gradients on observed quantities, PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES, Vol: 377, ISSN: 1364-503X
Carnielli G, Goland M, Leblanc F, et al., 2019, First 3D test particle model of Ganymede's ionosphere, ICARUS, Vol: 330, Pages: 42-59, ISSN: 0019-1035
Götz C, Gunell H, Volwerk M, et al., 2019, Cometary plasma science -- A white paper in response to the voyage 2050call by the European space agency, Publisher: arXiv
Comets hold the key to the understanding of our solar system, its formationand its evolution, and to the fundamental plasma processes at work both in itand beyond it. A comet nucleus emits gas as it is heated by the sunlight. Thegas forms the coma, where it is ionised, becomes a plasma and eventuallyinteracts with the solar wind. Besides these neutral and ionised gases, thecoma also contains dust grains, released from the comet nucleus. As a cometaryatmosphere develops when the comet travels through the solar system,large-scale structures, such as the plasma boundaries, develop and disappear,while at planets such large-scale structures are only accessible in their fullygrown, quasi-steady state. In situ measurements at comets enable us to learnboth how such large-scale structures are formed or reformed and how small-scaleprocesses in the plasma affect the formation and properties of these largescale structures. Furthermore, a comet goes through a wide range of parameterregimes during its life cycle, where either collisional processes, involvingneutrals and charged particles, or collisionless processes are at play, andmight even compete in complicated transitional regimes. Thus a comet presents aunique opportunity to study this parameter space, from an asteroid-like to aMars- and Venus-like interaction. Fast flybys of comets have made many newdiscoveries, setting the stage for a multi-spacecraft mission to accompany acomet on its journey through the solar system. This white paper reviews thepresent-day knowledge of cometary plasmas, discusses the many questions thatremain unanswered, and outlines a multi-spacecraft ESA mission to accompany acomet that will answer these questions by combining both multi-spacecraftobservations and a rendezvous mission, and at the same time advance ourunderstanding of fundamental plasma physics and its role in planetary systems.
Deca J, Henri P, Divin A, et al., Building a Weakly Outgassing Comet from a Generalized Ohm’s Law, Physical Review Letters, Vol: 123, ISSN: 0031-9007
Bockelée-Morvan D, Filacchione G, Altwegg K, et al., 2019, AMBITION -- Comet nucleus cryogenic sample return (white paper for ESA's voyage 2050 programme), Publisher: arXiv
This white paper proposes that AMBITION, a Comet Nucleus Sample Returnmission, be a cornerstone of ESA's Voyage 2050 programme. We summarise some ofthe most important questions still open in cometary science after the successesof the Rosetta mission, many of which require sample analysis using techniquesthat are only possible in laboratories on Earth. We then summarisemeasurements, instrumentation and mission scenarios that can address thesequestions, with a recommendation that ESA select an ambitious cryogenic samplereturn mission. Rendezvous missions to Main Belt comets and Centaurs arecompelling cases for M-class missions, expanding our knowledge by exploring newclasses of comets. AMBITION would engage a wide community, drawing expertisefrom a vast range of disciplines within planetary science and astrophysics.With AMBITION, Europe will continue its leadership in the exploration of themost primitive Solar System bodies.
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