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| Naji, M. |
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| Motta, Antonella |
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| Aletan, Dirar |
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| Mohamed, Tarek |
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| Ertürk, Emre |
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| Taccardi, Nicola |
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| Kononenko, Denys |
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| Petrov, R. H. | Madrid |
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| Alshaaer, Mazen | Brussels |
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| Bih, L. |
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| Casati, R. |
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| Muller, Hermance |
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| Kočí, Jan | Prague |
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| Šuljagić, Marija |
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| Kalteremidou, Kalliopi-Artemi | Brussels |
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| Azam, Siraj |
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| Ospanova, Alyiya |
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| Blanpain, Bart |
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| Ali, M. A. |
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| Popa, V. |
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| Rančić, M. |
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| Ollier, Nadège |
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| Azevedo, Nuno Monteiro |
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| Landes, Michael |
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| Rignanese, Gian-Marco |
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Zine, Sonia
Université Grenoble Alpes
in Cooperation with on an Cooperation-Score of 37%
Topics
Publications (10/10 displayed)
- 2018CONSERT probing of 67P/C-G nucleus during the ROSETTA mission, operations and results
- 2017 Interior of 67P/C-G comet as seen by CONSERT bistatic radar on Rosetta
- 2016Cosmochemical implications of CONSERT permittivity characterization of 67P/CG
- 2016Mineralogical implications of Consert permittivity characterization of 67P.
- 2016Cosmochemical implications of CONSERT permittivity characterization of 67P/C-G
- 2016Cosmochemical implications of CONSERT permittivity characterization of 67P/C-G
- 2016Mineralogical Implications of CONSERT Permittivity Characterization of 67P
- 2015Insights gained from Data Measured by the CONSERT Instrument during Philae's Descent onto 67P/C-G's surface
- 2015Properties of the 67P/Churyumov-Gerasimenko interior revealed by CONSERT radarcitations
- 2015The CONSERT Instrument during Philae's Descent onto 67P/C-G’s surface: Insights on Philae’s Attitude and the Surface Permittivity Measurements at the Agilkia-Landing-Site
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document
CONSERT probing of 67P/C-G nucleus during the ROSETTA mission, operations and results
Abstract
Thestructureandcompositionofcometarynucleiisoneofthemajorunknownsincometaryscience.ThesewerethescientificobjectivesoftheCometNucleusSoundingExperimentbyRadiowaveTransmission(CONSERT)aboardESAspacecraftRosetta. The knowledge of the interior is important to understandtheformationandevolutionofcomets.CONSERTwasabi-staticradarcomposedoftwoparts,oneonthelanderPhilaeonthecomet’ssurface,andanotheronRosettaspacecraft(Kofmanetal.,2007).CONSERToperatedduring9hoursafterthelandingandmademeasurementsthroughthesmalllobe(head)of67P/C-G.Theanalysisandinterpretationhavebeendoneusingmeasurements of the propagation time of the signal through thecomet,theshapeofthereceivedsignalsandthen3Dmodelingofthepropagationthroughthecomet.Themodellingandthepropagationtimeinsidethecometpermittoderivethebulkpermittivityvalue(=1.27)ofthecometaryinterior(Kofmanetal,2015).Permittivityvaluesforporousmixtureoficesanddustswerecomparedwithlaboratoryexperimentalvaluesinordertoobtainconstraintsonthepossibleconstituentsofthecometnucleus(ices,silicatesandorganics)anditsporosity(70-85%).The minimum required content of carbonaceous material is 75 %in volume. This suggests that comets represent a massive carbonreservoir(Kofmanetal.,2015,Heriqueetal.,2016).Theshapeofthesignal,veryclosetotheshapeofthecalibrationone,showsthatthescatteringbyinhomogeneitiesinthemediumisnotobservable.Thisindicatesthattheinteriorishomogenousatthescaleoffewwavelengths(Kofmanetal.,2015).3Dsimulationsofthesignalpropagationinnon-homogeneousmediahavebeenrun to define the sensitivity of CONSERT to inhomogeneities andtofindconstrainsontheinternalstructuresintermsofsizeandcomposition at a scale commensurate with the wavelength. Giventhehighbulkporosityofabout75%insidethesoundedpartofthe nucleus, a likely model would be obtained by a mixture, at this3-msizescale,ofvoids(vacuum)andblobswithmaterialmadeoficesanddustwithaporositylargerthan60%.Theabsenceofanypulsespreadingduetoscatteringallowsustoexcludeheterogeneity with higher contrast (0.25) and larger size (3m) (butremainingonthefewwavelengthsscale,sincelargerscalescanberesponsibleformultipathpropagation)(Ciarlettietal.,2017).Propertiesofmeterscaleinhomogeneitiesinsidethecometareessentialtounderstandcometaryformation.Theknowledgeofthe precise position of Philae on the comet, since the September2016, permitted to improve the determination of the propagationpathsinsidethecometandthereforetodescribebettertheinterior.TheinfluenceofthecloseenvironmentonantennaslobesandpolarizationwascalculatedusingtheDigitalTerrainModelofthelandingsiteandusedtostudythereceivedsignalpower.Wewilldescribeshortlymeasurementsthatexploredtheinteriorofthecomet,discussresults,theirinterpretationintermsoftheinternalstructureandcomposition.References[1]Ciarlettietal,CONSERTconstrainstheinternalstructureof67Patafewmetresizescale,MNRAS,469(Suppl.2),pp.S805-S817,2017[2]Heriqueetal,CosmochemicalimplicationsofCONSERTpermittivitycharacterizationof67P/CG,MNRAS462,S516-S532,2016[3]Kofmanetal,TheCometNucleusSoundingExperimentbyRadiowaveTransmission(CONSERT).SpaceScienceReviews,Volume 128, Issue 1-4, 413-432, 2007 [4] Kofman et al, Properties ofthe67P/Churyumov-GerasimenkointeriorrevealedbyCONSERTradar, Science, 349, 6247 aab0639, 2015.