Self-consistent Modelling of Mercury’s Surface Composition and Exosphere by Solar Wind Sputtering
dc.contributor.author
dc.date.accessioned
2017-02-17T08:07:59Z
dc.date.available
2017-02-17T08:07:59Z
dc.date.issued
2011-05-11
dc.identifier.isbn
978-84-87867-76-7
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dc.description.abstract
A Monte-Carlo model of exospheres was extended by treating the solar wind ion induced sputtering
process, quantitatively in a self-consistent way starting with the actual release of particles from the
mineral surface of Mercury. Mercury is a body without a significant atmosphere, thus, the surface is
effected by different processes that are mainly related to the radiation and plasma environment of
the Sun and to micrometeorites, which are delivered to Mercury’s surface. In such a case it can be
assumed that the composition of Mercury’s thin collisionless atmosphere, the exosphere, is related
to the composition of the planetary crustal materials. If so, then inferences regarding the bulk
chemistry of the planet can be made from a study of atoms and molecules in the exosphere after
they are released from the mineral surface by a variety of release processes. One difficult challenge
is the identification of the main source of some elements like H, He, Na or K. Generally it is
believed that H and He come primarily from the solar wind, while Na and K originate from
volatilized materials partitioned between Mercury’s crust and impacts from meteorites. Besides the
before mentioned elements corresponding to spectroscopic observations and experiments with soil
analogues, other elements such as O, Na, Mg, Al, Si, P, S, K, Ca, Ti, Cr, Fe, Ni, Zn, OH should also
be related with Mercury’s surface soils (Wurz et al., 2010, and references therein). Based on
available observational data and literature data we established a global model for the surface
mineralogy of Mercury and from that derived the average elemental composition of the surface.
Compositional data analysis has been employed for Mercury’s surface minerals recently by
(Sprague et al., 2009). In these cases the applied method was based on simple correlation methods,
which do not exploit the full potential of the available data. In addition, the closed nature of
compositional data, i.e., the assumption that component concentrations have to sum up to 100% in
an analysis, bears important implications for the statistical analysis of compositional data, which do
not seem to have been sufficiently appreciated until now. To investigate the default of the classical
additive analysis method our research group applied recently a more realistic multiplicative method
(Aitchison, 1986) based on the Euclidean space geometry of the simplex (see the chapter Elements
of simplicial linear algebra and geometry). Our recent results presented in detail in Wurz et al.,
(2010) for Mercury will be discussed. This model serves as a tool to estimate densities of species in
the exosphere depending on the release mechanism and the associated physical parameters
quantitatively describing the particle release from the surface
dc.format.mimetype
application/pdf
dc.language.iso
eng
dc.publisher
Universitat Politècnica de Catalunya. Centre Internacional de Mètodes Numèrics en Enginyeria (CIMNE)
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Reproducció digital del document publicat a:
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© International Workshop on Compositional Data Analysis (4th: 2011: Sant Feliu de GuÍxols, Girona). CODAWORK 2011: International Workshop on Compositional Data Analysis, hold on May 9-13rd. 2011, Sant Feliu de Guíxols, Girona
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Llibres / Capítols de LLibre (D-IMAE)
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Tots els drets reservats
dc.subject
dc.title
Self-consistent Modelling of Mercury’s Surface Composition and Exosphere by Solar Wind Sputtering
dc.type
info:eu-repo/semantics/bookPart
dc.rights.accessRights
info:eu-repo/semantics/openAccess