Electrical properties of cometary dust particles derived from line shapes of TOF-SIMS spectra measured by the ROSETTA/COSIMA instrument

Klaus Hornung (1) , Eva Maria Mellado (1) , John Paquette (2) , Nicolas Fray (3) , Henning Fischer (2) , Oliver Stenzel (2) , Donia Baklouti (4) , Sihane Merouane (2) , Yves Langevin (4) , Anais Bardyn (5) , Cecile Engrand (6) , Hervé Cottin (3) , Laurent Thirkell (7) , Christelle Briois (7) , Paola Modica (7) , Jouni Rynö (8) , Johan Silén (8) , Rita Schulz (9) , Sandra Siljestrom (10) , Harry Lehto (11) , Kurt Varmuza (12) , Andreas Koch , Jochen Kissel (2) , Martin Hilchenbach (2)

1 Universität der Bundeswehr München [Neubiberg]
2 MPS - Max-Planck-Institut für Sonnensystemforschung
3 LISA (UMR_7583) - Laboratoire Interuniversitaire des Systèmes Atmosphériques
4 IAS - Institut d'astrophysique spatiale
5 Carnegie Institution for Science
6 CSNSM - Centre de Sciences Nucléaires et de Sciences de la Matière
7 LPC2E - Laboratoire de Physique et Chimie de l'Environnement et de l'Espace
8 FMI - Finnish Meteorological Institute
9 ESA Scientific Support Office
10 RISE Research Institutes of Sweden
11 Tuorla Observatory
12 TU Wien - Vienna University of Technology

Between Aug. 2014 and Sept. 2016, while ESA’s cornerstone mission Rosetta was operating in the vicinity of the nucleus and in the coma of comet 67P/Churyumov-Gerasimenko, the COSIMA instrument collected a large number of dust particles with diameters up to a millimeter. Positive or negative ions were detected by a time-of-flight secondary ion mass spectrometer (TOF-SIMS) and the composition of selected particles was deduced. Many of the negative ion mass spectra show, besides mass peaks at the correct position, an additional, extended contribution at the lower mass side caused by partial charging of the dust. This effect, usually avoided in SIMS applications, can in our case be used to obtain information on the electrical properties of the collected cometary dust particles, such as the specific resistivity ( ρr > 1.2 ∙10^10 Ωm) and the real part of the relative electrical permittivity (ε < 1.2). From these values a lower limit for the porosity is derived (P > 0.8).

Keywords: Cometary dust; Rosetta mission; Electrical properties; Time-of-flight mass spectra; Sample charging

Domains: Space Physics [physics.space-ph]; Astrophysics [astro-ph]

Klaus Hornung, Eva Maria Mellado, John Paquette, Nicolas Fray, Henning Fischer, et al.. Electrical properties of cometary dust particles derived from line shapes of TOF-SIMS spectra measured by the ROSETTA/COSIMA instrument. Planetary and Space Science, 2020, 182, pp.104758. ⟨10.1016/j.pss.2019.104758⟩. ⟨insu-02309198⟩