Optical properties of cometary particles collected by COSIMA: Assessing the differences between microscopic and macroscopic scales
| Autor: | Sihane Merouane, Martin Hilchenbach, Rita Schulz, Jouni Rynö, Klaus Hornung, Mathieu Vincendon, Cecile Engrand, Jochen Kissel, Yves Langevin |
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| Přispěvatelé: | Institut d'astrophysique spatiale (IAS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS) |
| Jazyk: | angličtina |
| Rok vydání: | 2019 |
| Předmět: |
Physics
Range (particle radiation) 010504 meteorology & atmospheric sciences biology Comet Phase (waves) [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP] Astronomy and Astrophysics Scale (descriptive set theory) Astrophysics biology.organism_classification 01 natural sciences Reflectivity Lower half Wavelength Space and Planetary Science 0103 physical sciences Osiris 010303 astronomy & astrophysics 0105 earth and related environmental sciences |
| Zdroj: | Planetary and Space Science Planetary and Space Science, Elsevier, 2019, 182 (104815), ⟨10.1016/j.pss.2019.104815⟩ |
| ISSN: | 0032-0633 |
| Popis: | International audience; The COSIMA mass spectrometer on-board Rosetta was equipped with an optical microscope, Cosiscope, which identified several 10,000 cometary particles collected on targets exposed during the orbital phase around the nucleus of comet 67P Churyumov-Gerasimenko. The median value of reflectance factors evaluated from Cosiscope images for large collected particles (~10.5% (Langevin et al., 2017), lies above the range of reflectance observed by the OSIRIS camera at a similar wavelength (5-7%, (Fornasier et al., 2015), but at much larger scales (a few 10 cm instead of a few 10 μm). In order to better understand this discrepancy, the assumptions underlying the derivation of reflectance factors have been reassessed using laboratory measurements of COSIMA targets and analogs of cometary particles. The approach of Langevin et al. is validated, but we consider that the uncertainty on reflectance factors was conservative. The reflectance factors are likely to lie in the lower half of the previously estimated range, which reduces (but does not eliminate) the discrepancy with OSIRIS albedos. The remaining discrepancy can be attributed primarily to the difference in scale (factor 10,000 in pixel size between COSIMA and OSIRIS) |
| Databáze: | OpenAIRE |
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