C o M e C S - Project

Comet and Meteorite Materials - Studied by Chemometrics of Spectroscopic Data

Comet Samples / Overview (2017)

The typical exposure time for particle collection was about one week; distance to the comet surface was typical 10 - 200 km, distance to the Sun 1.2 - 4.7 AU. In total, during the more than two years next to the comet, COSIMA collected about 1400 particles or more than 30,000 particle fragments within 538 days net exposure time [7-9].

Sizes of the evaluated particles are between about 14 mm (pixel size) and 1000 mm; density was estimated as 0.2 - 0.3 g/cm³, and the porosity as >80% [10]. Most particles have an agglomerative, fluffy, porous structure. The impact speed of the particles was a few m/s and thus did not affect the chemical composition - contrary to the sampling with several km/s during the Stardust mission with samples returned to Earth [11, 12].

On about 250 selected particles TOF-SIMS spectra have been measured, showing a mixture of silicates and carbonaceous material (almost 50 % of mass [13]) similar to chondritic meteorites [14]. The atomic ratio C/Si was estimated as 5.5 (±1.3) [13], the atomic ratio N/C as 0.035 (±0.011) [15], and the carbon may be mostly present in macromolecular substances [16].

On metal targets (mostly Au) 1 cm x 1 cm more than 35,000 cometary particles were collected and imaged. Left: particle Kerttu (target 3D0); right: particle Sophie (target 2D0).

References

7. Y. Langevin, M. Hilchenbach, N. Ligier, S. Merouane, K. Hornung, C. Engrand, R. Schulz, J. Kissel, J. Rynö, P. Eng, Icarus, 271 (2016) 76-97. Typology of dust particles collected by the COSIMA mass spectrometer in the inner coma of 67P/Churyumov Gerasimenko.

8. S. Merouane, O. Stenzel, M. Hilchenbach, R. Schulz, N. Altobelli, H. Fischer, K. Hornung, J. Kissel, Y. Langevin, E.M. Mellado, J. Rynö, B. Zaprudin, MNRAS (Monthly Notices of the Royal Astronomical Society), 469 (2017) S459-S474. Evolution of the physical properties of dust and cometary dust activity from 67P/Churyumov-Gerasimenko measured in situ by Rosetta/COSIMA.

9. S. Merouane, B. Zaprudin, O. Stenzel, Y. Langevin, N. Altobelli, V. Della Corte, H. Fischer, M. Fulle, K. Hornung, J. Silen, N. Ligier, A. Rotundi, J. Rynö, R. Schulz, M. Hilchenbach, J. Kissel, Astron. Astrophys., 596 (2016) A87. Dust particle flux and size distribution in the coma of 67P/Churyumov-Gerasimenko measured in situ by the COSIMA instrument on board Rosetta.

10. K. Hornung, S. Merouane, M. Hilchenbach, Y. Langevin, E.M. Mellado, V. Della Corte, J. Kissel, C. Engrand, R. Schulz, J. Rynö, J. Silen, Planet. Space Sci., 133 (2016) 63-75. A first assessment of the strength of cometary particles collected in-situ by the COSIMA instrument onboard ROSETTA.

11. D. Brownlee, Annu. Rev. Earth Planet. Sci., 42 (2014) 179-205. The Stardust mission: Analyzing samples from the edge of the solar system.

12. T. Stephan, G.J. Flynn, S.A. Sandford, M.E. Zolensky, Meteoritics & Planetary Science, 43 (2008) 285-298. TOF-SIMS analysis of cometary particles extracted from Stardust aerogel.

13. A. Bardyn, D. Baklouti, H. Cottin, N. Fray, C. Briois, J. Paquette, O. Stenzel, C. Engrand, H. Fischer, K. Hornung, R. Isnard, Y. Langevin, H. Lehto, L. Le Roy, N. Ligier, S. Merouane, P. Modica, F.R. Orthous-Daunay, J. Rynö, R. Schulz, J. Silen, L. Thirkell, K. Varmuza, B. Zaprudin, J. Kissel, M. Hilchenbach, MNRAS (Monthly Notices of the Royal Astronomical Society), 0 (2017) in print. Carbon-rich dust in comet 67P/Churyumov-Gerasimenko measured by COSIMA/Rosetta.

14. O. Stenzel, M. Hilchenbach, S. Merouane, J. Paquette, K. Varmuza, C. Engrand, F. Brandstätter, C. Koeberl, L. Ferrière, P. Filzmoser, S. Siljeström, MNRAS (Monthly Notices of the Royal Astronomical Society), 0 (2017) in print. Similarities in element content between comet 67P/Churyumov-Gerasimenko coma dust and selected meteorite samples.

15. N. Fray, A. Bardyn, H. Cottin, D. Baklouti, C. Briois, C. Engrand, H. Fischer, K. Hornung, R. Isnard, Y. Langevin, H. Lehto, L. Le Roy, E.M. Mellado, S. Merouane, P. Modica, F.R. Orthous-Daunay, J. Paquette, J. Rynö, R. Schulz, J. Silen, S. Siljeström, O. Stenzel, L. Thirkell, K. Varmuza, B. Zaprudin, J. Kissel, M. Hilchenbach, MNRAS (Monthly Notices of the Royal Astronomical Society), 469 (2017) S506-S516. Nitrogen-to-carbon atomic ratio measured by COSIMA in the particles of comet 67P/Churyumov-Gerasimenko.

16. N. Fray, A. Bardyn, H. Cottin, K. Altwegg, D. Baklouti, C. Briois, L. Colangeli, C. Engrand, H. Fischer, A. Glasmachers, E. Grün, G. Haerendel, H. Henkel, H. Höfner, K. Hornung, E.K. Jessberger, A. Koch, H. Krüger, Y. Langevin, H. Lehto, K. Lehto, L. Le Roy, S. Merouane, P. Modica, F.R. Orthous-Daunay, J. Paquette, F. Raulin, J. Rynö, R. Schulz, J. Silen, S. Siljeström, W. Steiger, O. Stenzel, T. Stephan, L. Thirkell, R. Thomas, K. Torkar, K. Varmuza, K.P. Wanczek, B. Zaprudin, J. Kissel, M. Hilchenbach, Nature, 528 (2016) 72-74. High-molecular-weight organic matter in the particles of comet 67P/Churyumov-Gerasimenko.

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