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CLASSY cooperative project
Funded by Agence Nationale de la Recherche (ANR) - (2018-2022)
Our Solar System is the only planetary system that can be thoroughly
explored by spacecrafts and by the analysis of planetary samples in the
laboratory. It provides a unique glance at the mechanisms leading to
stars and planets formation, a vision that is complementary to that
derived from remote observations of nascent planetary systems.
Chemical, dynamical and chronological information is trapped in the
more primitive bodies that escaped extensive planetary evolution, as
asteroids, comets and Kuiper Belt Objects (KBOs). The composition of
these so-called small bodies then constitutes a major and outstanding
spectro-photometry allows for systematic surveys and therefore provides
a global appraisal of the compositional diversity of the small body
population as a whole. However, the composition of dark small bodies
remains poorly known and presently, a number of fundamental issues are
still pending :
The interpretation of VNIR spectra is the angular stone of all these issues and the central objective of CLASSY.
Our proposal arises in the general context of a wealth of data
collected by the space missions ROSETTA, DAWN and NEW HORIZONS. We
benefit from high quality and high spatial resolution multi-angular
VNIR observations with unprecedented photometric accuracy. The
interpretation of these data will lead to major results on the
composition of a comet (67P/CG), the type C asteroid Ceres and KBO 2017
MU 69, shading new light on the interpretation of the taxonomic
spectral classes in term of composition, and on the asteroid-comet
continuum. However, this interpretation requires experimental data that
have not been measured so far.
CLASSY aims at
conducting these experiments and interpreting the spectral data from
the space missions mentionned above. We will study experimentally the
effects of the first stages of space weathering (ions irradiation) on
the VNIR spectra of dark analogs, and investigate the composition and
textural parameters that control VNIR spectra through multi-angular
radio-spectro-goniometric measurements on sub-micrometric
The CLASSY consortium is multidisciplinary and includes 5 laboratories :
- What composition is associated with each taxonomic spectral class ?
- Does space weathering play a role in the definition of taxonomic spectral classes ?
- How are they linked with available cosmomaterials ?
- Institut de Planetologie et d’Astrophysique de Grenoble (IPAG, Grenoble): P. Beck, L. Bonal, O. Brissaud, L. Flandinet, O. Poch, E. Quirico, B. Schmitt
- IAS (Institut d’Astrophysique Spatiale, Orsay): A. Aleon-Toppani, D. Baklouti, R. Brunetto, C. Lantz and Z. Djouadi.
- Unite Materiaux et Transformations (UMET, Lille): F. De la Pena, C. Depecker, C. Le Guillou, H. Leroux
- Laboratoire d’Etudes Spatiales et Instrumentations en Astrophysique (LESIA, Meudon): A. Barucci, S. Erard, S. Fornasier, F. Merlin
- Museum National d’Histoire Naturelle (MNHN): M. Roskosz
CLASSY gathers a broad range of fields as Planetary and Space sciences,
Surface sciences, Material Sciences, Meteoritics, Mineralogy,
Irradiation physics and Data science. Most of researchers belonging to
this consortium have been used to collaborate together, and they share
many common publications. CLASSY offers the opportunity to strengthen
these collaborations, and to provide innovative in- terpretations and
breakthrough of data collected by space missions of primary interest.
It will also form a internationally competitive team that will apply
for grains that will be returned back to Earth by the Hayabusa 2 and
CLASSY is organized along 3 main tasks:
Task 1: Ion
irradiation experiments that aim at investigating the first stage of
space weathering, as the effects of solar wind irradiation on dark
surfaces analogs and carbonaceous chondrites. The samples will be
characterized with microanalytical techniques, before and after
irradiation, and their spectral properties characterized as well.
Task 2: Multi-angular
reflectance experiments that aim at studying the spectral reflectance
properties of dark small bodies analogs and carbonaceous chondrites,
and irradiated samples as well (Task 1). High signal-to-noise ratio and
multi-angular bi-directional reflec- tance data will be collected with
a unique home-made instrument designed and built at IPAG.
Submicrometric fine-grained porous analogs will be produced through
Task 3: Interpretation
of spectral data of dark small bodies based on Tasks 1 and 2, in
particular those collected by the space missions Rosetta, Dawn and New
Horizons, for which multi-angular and extensive independent constraints
on surface composition are available.