Low velocity collisions of porous planetesimals in the early solar system

Niem, D. de; Kührt, Ekkehard; Hviid, S. F.; Davidsson, B.

doi:10.1016/j.icarus.2017.09.024

Cited by 9 publications

(7 citation statements)

References 52 publications

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“…Conversely, other measurements suggest a different formation process: 1) the elemental abundances of many species (C, O, etc) are close to the solar values; 2) the organic matter abundance is similar to molecular clouds and star-forming regions; 3) the nonsolar values of the isotopic ratios of Si, Xe, and S and 4) the high [D 2 O/HDO]/[HDO/H 2 O] value measured on 67P/CG are compatible with a scenario in which comets were formed very far from the Sun from presolar matter mixed with never-sublimated (amorphous) ice, at temperature as low as 20 K and in a poorly mixed protoplanetary disk (Altwegg et al 2019). Differently from larger bodies orbiting closer to the Sun that have sustained thermal processing, impacts, and chemical alterations (de Niem et al 2018), comets preserve their original composition being relegated to the outer Solar System for great part of their lifetimes. Comets are currently stored in two large reservoirs, e.g.…”

Section: Introductionsupporting

confidence: 72%

Comet nuclei composition and evolution

Filacchione¹,

Ciarniello²,

Fornasier³

et al. 2022

Preprint

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Thanks to Rosetta orbiter's and Philae lander's data our knowledge of cometary nuclei composition has experienced a great advancement. The properties of 67P/Churyumov-Gerasimenko nucleus are discussed and compared with other comets explored in the past by space missions. Cometary nuclei are made by a collection of ices, minerals, organic matter, and salts resulting in very dark and red-colored surfaces. When relatively far from the Sun (> 3AU), exposed water and carbon dioxide ices are found only in few locations of 67P/CG where the exposure of pristine subsurface layers or the recondensation of volatile species driven by the solar heating and local terrain morphology can sustain their temporary presence on the surface. The nucleus surface appears covered by a dust layer of variable thickness caused by the back-fall flux of coma grains. Depending on local morphology, some regions are less influenced by the back-fall and show consolidated terrains. Dust grains appear mostly dehydrated and are made by an assemblage of minerals, organic matter, and salts mixed together. Spectral analysis shows that the mineral phase is dominated by silicates and fine-grained opaques (possibly including Fe-sulfides such as troilite or pyrrhotite), and ammoniated salts. Aliphatic and aromatic groups, with the presence of the strong hydroxyl group, are identified within the organic matter. The surface composition and physical properties of cometary nuclei evolve with heliocentric distance and seasonal cycling: approaching perihelion the increase of the solar flux boost the activity through the sublimation of volatile species which in turn causes the erosion of surface layers, the exposure of ices, the activity in cliffs and pits, the collapse of overhangs and walls, and the mobilization and redistribution of dust. The evolution of color, composition, and texture changes occurring across different morphological and geographical regions of the nucleus are correlated with these processes. In this chapter we discuss 67P/CG nucleus composition and evolutionary processes as observed by Rosetta mission in the context of other comets previously explored by space missions or observed from Earth.

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Section: Introductionsupporting

confidence: 72%

Comet nuclei composition and evolution

Filacchione¹,

Ciarniello²,

Fornasier³

et al. 2022

Preprint

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“…Driven by accretion, these grains formed comets and planetesimals (Skorov and Blum 2012), the building blocks of the solid bodies of our solar system. Although processed by impacts, comets have not experienced a significant heating and alteration of their solid materials (de Niem et al 2018). Differently from asteroids and larger bodies, on comets the imprint of pre-solar materials has been preserved (Mumma and Charnley 2011).…”

mentioning

confidence: 99%

Comet 67P/CG Nucleus Composition and Comparison to Other Comets

et al. 2019

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HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

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“…A spherical body with radius of 10 km consisting of particles having the same compression property as 1.7 m silica beads was shown to have bulk porosity of 82% (Omura and Nakamura, 2018). Numerical simulations of collisional processes have been tested by reproducing laboratory results of non-porous and porous targets for the purpose of effective modeling of collisional processes of small bodies (e.g., Benz and Asphaug, 1994;Jutzi et al, 2009;de Niem, et al, 2018). However, porous small bodies can have a variety of internal structures (Nakamura et al, 2009), so laboratory experiments and numerical simulations covering wide parameter space are useful for understanding the collision process and studying the collisional evolution of small bodies.…”

Section: Introductionmentioning

confidence: 99%

Collisional disruption of highly porous targets in the strength regime: Effects of mixture

Murakami

Nakamura

Yokoyama

et al. 2020

Planetary and Space Science

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Highly porous small bodies are thought to have been ubiquitous in the early solar system. Therefore, it is essential to understand the collision process of highly porous objects when considering the collisional evolution of primitive small bodies in the solar system. To date, impact disruption experiments have been conducted using high-porosity targets made of ice, pumice, gypsum, and glass, and numerical simulations of impact fracture of porous bodies have also been conducted. However, a variety of internal structures of high-porosity bodies are possible. Therefore, laboratory experiments and numerical simulations in the wide parameter space are necessary.In this study, high-porosity targets of sintered hollow glass beads and targets made by mixing perlite with hollow beads were used in a collision disruption experiment to investigate the effects of the mixture on collisional destruction of high-porosity bodies.Among the targets prepared under the same sintering conditions, it was found that the targets with more impurities tend to have lower compressive strength and lower resistance against impact disruption. Further, destruction of the mixture targets required more impact energy density than would have been expected from compressive strength. It is likely that the perlite grains in the target matrix inhibit crack growth through the glass framework. The mass fraction of the largest fragment collapsed to a single function of a scaling parameter of energy density in the strength regime ( ) when assuming ratios of tensile strength to compressive strength based on a relationship obtained for ice-silicate mixtures. However, the dependence on is much larger than that shown for porous targets with different internal microstructures from the targets in this study. The depth of the deep cavity specific to the high-porosity target was well represented by a dimensionless parameter using the compressive strength of both the pure glass and mixture targets. The empirical relationship of cavity depth was shown to hold for various targets used in previous studies irrespective of the internal microstructure of the targets.

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Low velocity collisions of porous planetesimals in the early solar system

Cited by 9 publications

References 52 publications

Comet nuclei composition and evolution

Comet nuclei composition and evolution

Comet 67P/CG Nucleus Composition and Comparison to Other Comets

Collisional disruption of highly porous targets in the strength regime: Effects of mixture

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