Laboratory Simulation of Cometary Processes: Results from First Kosi Experiments

Grün, E.; Bar‐Nun, A.; Benkhoff, J.; Bischoff, A.; Düren, H.; Hellmann, H.; Hesselbarth, P.; Hsiung, P.; Keller, H. U.; Klinger, J.; Knölke, J.; Kochan, H.; Kohl, H.; Kölzer, G.; Krankowsky, D.; Lämmerzahl, P.; Mauersberger, K.; Neukum, G.; Oehler, A.; Ratke, Lorenz; Roessler, Κ.; Schwehm, G.; Spohn, Tilman; Stöffler, D.; Thiel, K.

doi:10.1017/s0252921100109728

Cited by 6 publications

(5 citation statements)

References 37 publications

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“…The KOSI laboratory experiments in the 1990s simulated and studied sublimation processes that were expected on the surfaces of comets (e.g., Grün et al 1989Grün et al , 1993Lämmerzahl et al 1995). In a sublimation chamber, mixtures of water ice and nonvolatile analog materials were illuminated by an energy source and the changes in the samples' surfaces were analyzed.…”

Section: Introductionmentioning

confidence: 99%

Sublimation of ice-dust mixtures in cooled vacuum environments to reproduce cometary morphologies

Haack

Lethuillier

Kreuzig

et al. 2021

A&A

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Aims. The morphology of cometary surfaces can provide important information to constrain the composition and evolution of comets. In this work, we investigate the sublimation behavior of comet analog materials and how the sample composition affects the evolution of morphological features in laboratory experiments. In our experiments, we used dust ice mixtures as analog material to form observed cometary morphologies. Methods. We used ice-dust mixtures in different mixing ratios as cometary analog material. In order to obtain realistic results, we scaled the expected cohesive and gravitational forces on comets to laboratory conditions. The samples were placed in a vacuum sublimation chamber and permanently cooled down to temperatures below 150 K to simulate the space environment. In the experiment, the samples were insolated with a light source from two different directions and alterations on the surface were recorded with a camera. Results. We find that the morphology of sublimation residues of ice-dust mixtures is strongly dependent on the ice-dust ratio as well as the insolation direction. High amounts of ice cause constant surface alteration and lead to exotic morphologies. Low amounts cause fewer and more episodic surface changes during its sublimation. Collapse events resulting in irregular and very rough surfaces occur during horizontal insolation.

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Section: Introductionmentioning

confidence: 99%

Sublimation of ice-dust mixtures in cooled vacuum environments to reproduce cometary morphologies

Haack

Lethuillier

Kreuzig

et al. 2021

A&A

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“…Through this process a comet loses material during each orbit until it finally extinguishes. In the 1990s sublimation experiments with dust-ice mixtures were performed as part of the KOSI (KOmetenSImulation) project to simulate and understand these cometary surface processes (e.g., Grün et al 1989Grün et al , 1993Lämmerzahl et al 1995). However, these experiments are not suitable and were not designed to understand complex morphologies such as cliffs, cracks, or mass movements that have only later been observed on 67P/Churyumov-Gerasimenko (Thomas et al 2015;Pajola et al 2016;El-Maarry et al 2019).…”

Section: Introductionmentioning

confidence: 99%

Tensile strength of dust-ice mixtures and their relevance as cometary analog material

Haack

Otto

Gundlach

et al. 2020

A&A

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Aims. The tensile strength of granular matter is of great importance to our understanding of the evolution of comets and to our attempts to reproduce processes on cometary surfaces in laboratory experiments. In this work, we investigate the tensile strength of three different materials and their mixtures, which can be used as cometary analog materials in the laboratory. Methods. We used two types of siliceous dusts and granular water ice whose polydisperse particles were either angular or spherical. Our samples were cooled to below 150 K to better simulate the conditions of a cometary surface and to avoid thermal alteration of the material. We used the Brazilian disk test method to exert stress on the cooled samples and determine the tensile strength at the moment the samples broke. Results. We find that the tensile strength of two component mixtures is strongly dominated by the component with the higher tensile strength. The materials made of mostly angular dust particles have a lower filling fraction, but a higher tensile strength compared to materials made of spherical particles. Furthermore, the tensile strength of the cooled components is substantially lower than the tensile strength of the same components at room temperature. This implies that the surface energy of the investigated materials at low temperatures is significantly lower than previously assumed.

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“…This model was improved many times [12] afterward. Nuclei of the majority of comets are coated by dust layers, this is shown by laboratory simulation [4,6,7], theoretical calculations [10,12,13] and observations. The dust mantle prevents ice of a cometary nucleus from direct heating by solar radiation.…”

Section: Introductionmentioning

confidence: 94%

Effect of enhanced sublimation from an active region of a cometary nucleus

Иванова

Shulman

2003

AstSR

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Preliminary results of calculation of the effect of amplification of sublimation due to concentration of the solar radiation by a conical hole in the surface dust layer on a cometary nucleus are given. The temperature of ice on the bottom of the crater is calculated for different geometrical parameters of the crater. The dependence of the effect of intensification of sublimation on the geometrical parameters is considered for a specific case when a single active region is exactly on the pole of the nucleus and this pole is directed to the Sun. ЭФФЕКТ УСИЛЕНИЯ СУБЛИМАЦИИ ИЗ АКТИВНЫХ ОБЛАСТЕЙ КОМЕТНОГО ЯДРА, Иванова А.В., Шульман Л.М. Рассматриваются предварительные результаты расчета эффекта усиления сублимации путем концентрации солнечного излучения коническим отверстием в пылевом слое кометного ядра. Рассчитана температура льда на дне кратера в зависимости от его геометрических параметров и эффект усиления сублимации. Рассмотрена зависимость усиления сублимации от геометрических параметров для частного случая, когда единственная активная область находится точно на полюсе ядра и полюс обращен к Солнцу. ЕФЕКТ ПIДСИЛЕННЯ СУБЛIМАЦIЇ З АКТИВНИХ ОБЛАСТЕЙ КОМЕТНОГО ЯДРА, Iванова О.В., Шульман Л.М. Розглядаються попереднi результати розрахунку ефекту пiдсилення сублiмацiї криги шляхом концентрацiї сонячного випромiнювання конiчним отвором в пиловому шарi кометного ядра. Розраховано температуру на днi кратера в залежностi вiд його геометричних параметрiв, та ефект пiдсилення сублiмацiї.

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Laboratory Simulation of Cometary Processes: Results from First Kosi Experiments

Cited by 6 publications

References 37 publications

Sublimation of ice-dust mixtures in cooled vacuum environments to reproduce cometary morphologies

Sublimation of ice-dust mixtures in cooled vacuum environments to reproduce cometary morphologies

Tensile strength of dust-ice mixtures and their relevance as cometary analog material

Effect of enhanced sublimation from an active region of a cometary nucleus

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