Flattened loose particles from numerical simulations compared to particles collected by Rosetta

Lasue, J.; Maroger, Isabelle; Botet, Robert; Garnier, Philippe; Merouane, S.; Mannel, Thurid; Levasseur-Regourd, Anny Chantal; Bentley, Mark S.

doi:10.1051/0004-6361/201834766

Cited by 14 publications

(15 citation statements)

References 37 publications

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“…This finding is in agreement with the observation of the COSIMA instrument, detecting a lack of tens of micrometersized or smaller dust particles in the coma of comet 67P (Merouane et al 2017). Thus, it seems probable that the size of the particles observed by MIDAS is mainly created by fragmentation, which should depend on the initial size before impact, impact speed (Ellerbroek et al 2017), and the interconnected properties such as density and porosity, as well as cohesion (Lasue et al 2019). Thus, it should be noted that all size distributions discussed in Sect.…”

Section: Basic Statistics Of Midas Particlesmentioning

confidence: 99%

“…As the choice of h is crucial, but since the expected MIDAS cluster size is unknown, we orientate on the results of other Rosetta dust instruments and laboratory experiments to set a reasonable value. The bandwidth should be a strong function of the impact velocities as well as initial particle sizes and material strengths (Ellerbroek et al 2017;Lasue et al 2019). However, Ellerbroek et al (2017) found that a large mass loss of the parent particle on impact can be expected in certain cases.…”

Section: Dust Collection Processmentioning

confidence: 99%

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Cometary dust collected by MIDAS on board Rosetta

Kim¹,

T.²,

Boakes³

et al. 2023

A&A

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Context. The Micro-Imaging Dust Analysis System (MIDAS) atomic force microscope (AFM) on board the Rosetta comet orbiter has been dedicated to the collection and 3D topographical investigation of cometary dust in the size range of a few hundreds of nanometers to tens of micrometers with a resolution down to a few nanometers. Aims. We aim to catalog all dust particles collected and analyzed by MIDAS, together with their main statistical properties such as size, height, basic shape descriptors, and collection time. Furthermore, we aim to present the scientific results that can be extracted from the catalog, such as the size distribution and statistical characteristics of cometary dust particles. Methods. The starting point for this work was the existing MIDAS particle catalog, which has been greatly improved by a careful re-analysis of the AFM images, leading to the addition of more dust particles and a detailed description of the particle properties. The final product is a comprehensive list of all possible cometary dust particles detected by MIDAS. The catalog documents all images of identified dust particles and includes a variety of derived information tabulated one record per particle. Furthermore, the best image of each particle was chosen for subsequent studies. Finally, we created dust coverage maps and clustering maps of the MIDAS collection targets and traced any possible fragmentation of collected particles with a detailed algorithm. Results. The revised MIDAS catalog includes 3523 MIDAS particles in total, where 1857 particles are expected to be usable for further analysis (418 scans of particles before perihelion + 1439 scans of particles after perihelion, both after the removal of duplicates), ranging from about 40 nm to about 8 µm in size. The mean value of the equivalent radius derived from the 2D projection of the particles is 0.91 ± 0.79 µm. A slightly improved equivalent radius based on the particle's volume coincides in the range of uncertainties with a value of 0.56 ± 0.45 µm. We note that those sizes and all following MIDAS particle size distributions are expected to be influenced by the fragmentation of MIDAS particles upon impact on the collection targets. Furthermore, fitting the slope of the MIDAS particle size distribution with a power law of a • r b yields an index b of ∼ -1.67 to -1.88. Lastly, based on the created dust coverage maps and clustering maps of the MIDAS collection targets, we determined the particle fragmentation ratio of 4.09 for nominal activity and 11.8 for the outburst, which underlines that parent particles with faster impact velocity are more likely to be fragmented during dust collection.

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Section: Basic Statistics Of Midas Particlesmentioning

confidence: 99%

Section: Dust Collection Processmentioning

confidence: 99%

Cometary dust collected by MIDAS on board Rosetta

Kim¹,

T.²,

Boakes³

et al. 2023

A&A

Self Cite

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“…To study the physical properties of the dust particles coming from different regions, we analysed the dust shape distribution on the four targets. The parameter used as shape descriptor is the flatness (or aspect ratio), defined as = h / √ A , where h and A are the particle height and area, respectively (Lasue et al 2019 ;Kim et al, in preparation). A small F (i.e.…”

Section: Midasmentioning

confidence: 99%

Combining Rosetta’s GIADA and MIDAS data: morphological versus dynamical properties of dust at 67P/Churyumov–Gerasimenko

Longobardo

Mannel

Kim

et al. 2022

Monthly Notices of the Royal Astronomical Society

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We related morphological (size/shape) and dynamical properties of the dust ejected from the 67P/Churyumov-Gerasimenko comet by combining data from two instruments onboard the ESA's Rosetta mission, i.e., the MIDAS atomic force microscope and the GIADA dust detector. The two instruments detected dust of different size (10−6-10−5 and 10−4-10−3 m, respectively). MIDAS detected dust in four periods, three during the inbound orbit arc (September-November 2014; December 2014-February 2015; February-March 2015) and one corresponding to a post-perihelion outburst (19th February 2016). For these periods, we analysed the dust particles’ spatial distribution on the MIDAS targets to obtain the number of parent particles hitting the instrument by means of an empirical procedure and to measure the corresponding dust flux. For the same periods, we retrieved the dust flux measured by GIADA. The ratio between the two dust fluxes is constant. By coupling this result with activity models, we inferred that the particles detected by MIDAS are fragments of hundreds-micron- to mm-sized particles detected by GIADA. In addition, the similar dust flux ratios between nominal activity and outburst indicates that the outburst did not include micro- and nano-sized dust, differently from other outbursts previously observed. Dust and surface properties were related by applying a traceback algorithm to GIADA data to retrieve the source regions of dust ejected in different periods. We did not detect variations of morphological properties between dust ejected from more and less processed terrains, concluding that compact dust particles (detected by MIDAS) have the same properties across the comet surface.

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“…They likely resulted from submicron-sized grains accreted at low collision velocities, with further addition of minerals processed near the proto-Sun [e.g. [15][16]. At the Late Heavy Bombardment epoch, enormous influxes of interplanetary dust might then have provided a massive delivery of cometary carbonaceous compounds on telluric planets [1; 17].…”

Section: Significance Of the Results Back In Time And Beyond In Spacementioning

confidence: 99%

Linear polarization as a tool to characterize interplanetary, cometary, and extrasolar dust particles

Levasseur-Regourd

Lasue

Milli

et al. 2024

Preprint

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Summary Linear polarization observations have suggested the presence of dust particles that scatter solar light within cometary comae and the interplanetary dust cloud. Recent progresses result from in-situ observations or remote observations from large telescopes, while avoiding contamination from atmospheric airglow. The interpretation of polarimetric observations, at given phase angles and wavelengths, is a powerful tool to better understand the composition and physical properties of these irregular dust particles and their formation processes. It now provides clues to the origin of the Solar System and to some characteristics of dust in stellar systems, as discussed in [1]. <ol> <li> Zodiacal light polarization</li> </ol> Along a line-of-sight within the interplanetary dust cloud, both solar distance (R) and phase angle (a) vary, meaning that the intensity and linear polarization (P) of solar light scattered by interplanetary dust (i.e. zodiacal light) need to be inverted to retrieve some local properties. In the near-ecliptic symmetry plane of the cloud, P(a) phase curves are smooth, with a slightly negative branch below 20&#176; and a maximum by 90&#176;. For a constant a=90&#176;, P increases with R, at least between 0.5 au and 1.5 au. Numerical and experimental simulations (in the laboratory and under microgravity conditions) of such results suggest i) the presence in dust of low-absorbing minerals and absorbing complex organics, with a significant amount of fluffy aggregates, ii) some sublimation of semi-volatile organics with decreasing R and increasing temperatures [2; also 3-5 for reviews]. <ol start="2"> <li> Cometary dust polarization </li> </ol> In situ observations have, up to now, only been done on board Giotto during its flybys, allowing us to suggest the presence of a fragment in the coma of 26P/Grigg-Skjellerup and to derive very low values for geometric albedos (about 3%) and densities (50 to 500 kg m&#8722;3) of 1P/Halley dust particles [6-7]. Dust whole-coma remote observations, which avoid contamination from gaseous emissions with narrow interference filters, have been used by various teams to obtain P(a) phase curves. As for the zodiacal light, they are smooth; also P (whenever positive) increases with wavelenght for a given a. Numerical and experimental simulations are consistent with a dust population of irregular and possibly fractal structure, with complex optical indices suggesting mixtures of minerals and more absorbing organics [8-10]. Polarimetric in situ observations and remote imaging of comae (at given phase and wavelenght) suggest that the properties of dust are quite different in dust jets than elsewhere in a dust coma, and in Oort-cloud comets than in periodic comets [9, 11-12]. Such trends fairly agree with the ground-truth provided by the Rosetta rendezvous with 67P/Churyumov-Gerasimenko [13 for a review]. Finally, experimental simulations of 67P pre-perihelion brightness phase curves provide clues to an important amount of organic compounds and to fluffy aggregates with sizes above 10 micrometres [14]. <ol start="3"> <li> Significance of the results, back in time and beyond in space </li> </ol> Back in time, polarimetric results on cometary dust contribute to a better understanding of the formation of dust particles, in external regions of the protosolar disk. They likely resulted from submicron-sized grains accreted at low collision velocities, with further addition of minerals processed near the proto-Sun [e.g. 15-16]. At the Late Heavy Bombardment epoch, enormous influxes of interplanetary dust might then have provided a massive delivery of cometary carbonaceous compounds on telluric planets [1; 17]. Beyond in space, properties of interplanetary dust may suggest improvements in the modelling of observations of protoplanetary and debris disks. Updating results on the modelling of the dust continuum emission of the protoplanetary disk around MWC 758 [18], with moderately porous spherical particles and the above-mentioned phase functions retrieved by Rosetta, provides a better agreement between synthetic and observed maps of emission at sub-millimetre wavelengths. Besides, observations of debris disks have now shown that light scattering properties of dust in debris disks are far from those predicted by Mie theory and in favour of irregular dust particles, as pointed out essentially by phase functions analysis [19-20]. These results can greatly benefit from in situ and remote cometary observations and from advanced modelling of cometary dust, and at the same time provide examples of dust properties in other stellar systems to put our own Solar System into context [1]. <ol start="4"> <li> Conclusions and perspectives </li> </ol> Polarimetric observations of dust clouds in the Solar System provide clues to the properties of dust particles within cometary comae and the zodiacal cloud. Such results are already noticed to improve the modelling of dust in protoplanetary and debris disks, through the use of irregular porous particles properties instead of more conventional compact spherical ones. Comet Interceptor, ESA F-Class mission to an Oort-cloud comet, to be launched in 2028, should provide a better understanding of its local polarimetric properties with EnVisS experiment. Meanwhile, remote polarimetric observations of comets might contribute to the target selection. References [1] Levasseur-Regourd, A.C. et al., PSS, 186, 104896, 2020. [2] Hadamcik, E. et al., PSS, 183, 104527, 2020. [3] Levasseur-Regourd, A.C. et al.: In Interplanetary dust, E. Gr&#252;n et al. eds, Springer, 57-94, 2001. [4]&#160;Lasue, J. et al., In Polarimetry of stars and planetary systems, L. Kolokolova et al. eds, CUP, 419-436, 2015. [5] Lasue et al., PSS, 104973, 2020 (in press). [6] Levasseur-Regourd et al., PSS, 41, 167-169, 1993. [7] Fulle, M. et al., AJ, 119, 1968-1977, 2000. [8]&#160;Lasue, J. et al., Icarus, 199, 129-144, 2009. [9] Kiselev, N. et al., In Polarimetry of stars and planetary systems, L. Kolokolova et al. eds, CUP, 379-404, 2015. [10] Mu&#241;oz, O. et al., ApJ, 247:19, 2020. [11] Hadamcik, E. et al., MNRAS, 462, S507-S515, 2017. [12] Rosenbush, V.K., et al., MNRAS, 469, S475-S491, 2017. [13] Levasseur-Regourd, A.C. et al., Space Sci. Rev., 214:64, 2018. [14] Levasseur-Regourd, A.C. et al., A&A, 630, A20, 2019. [15] Fulle, M. & Blum, J., MNRAS. 469, S39-S44, 2017. [16] Lasue, J. et al., A&A, 630, A28, 2019. [17] Nesvorny&#769;, D., et al., ApJ, 713, 816-836, 2010. [18] Baruteau, C., et al., MNRAS, 486, 304-319, 2019. [19] Milli, J., et al., A&A, 599, A108, 2017. [20] Milli, J., et al., A&A, 626, A54, 2019. &#160;

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Flattened loose particles from numerical simulations compared to particles collected by Rosetta

Cited by 14 publications

References 37 publications

Cometary dust collected by MIDAS on board Rosetta

Cometary dust collected by MIDAS on board Rosetta

Combining Rosetta’s GIADA and MIDAS data: morphological versus dynamical properties of dust at 67P/Churyumov–Gerasimenko

Linear polarization as a tool to characterize interplanetary, cometary, and extrasolar dust particles

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