Article
Astronomy & Astrophysics
Bjorn J. R. Davidsson, Bonnie J. Buratti, Michael D. Hicks
Summary: In this study, we investigate the level of albedo variegation on the nucleus of Comet 67P/Churyumov-Gerasimenko. The observed albedo variegation is strongly related to the nucleus morphology, with smooth terrain being brighter and consolidated terrain being darker. We find that smooth terrain darkens before morphological changes and that stratigraphically low terrain is brighter than stratigraphically high terrain. The observed albedo variegation is attributed to differences in porosity and the coherent effect, where compaction causes brighter small particles to act collectively as darker larger particles.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Martin Rubin, Kathrin Altwegg, Jean-Jacques Berthelier, Michael R. Combi, Johan De Keyser, Stephen A. Fuselier, Tamas Gombosi, Murthy S. Gudipati, Nora Hanni, Kristina A. Kipfer, Niels F. W. Ligterink, Daniel R. Muller, Yinsi Shou, Susanne F. Wampfler
Summary: This study analyzes experimental data from the Rosetta mission at comet 67P and reveals that highly volatile species are trapped in H2O and CO2 ices. The study also suggests that CO2 is seasonal frost and finds an elevation in CO abundance during a certain period, which requires further investigation.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Marcin Wesolowski
Summary: The paper discusses several mechanisms that play a significant role in the formation of dune structures on comet surfaces. These mechanisms include dust migration, local avalanches resulting from landslides, and fluidization of unstable dust, all of which are initiated by ice sublimation. Due to the complex nature of cometary nuclei, the movement of dust may abruptly cease, leading to the formation of dune structures by particle piling. The maximum angular width, particle mobility coefficient, and static fluidization pressure were determined for each mechanism.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Daniel Gardener, Colin Snodgrass, Nicolas Ligier
Summary: This article introduces a pipeline that calibrates and measures the photometry of comet 67P during its 2016 perihelion passage. The results show that the activity levels of the comet do not change significantly from orbit to orbit, and the colors of the coma remain constant throughout the apparition. An outburst was also detected, which is consistent with the outbursts observed on the nucleus by Rosetta.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Mauro Ciarniello, M. Fulle, F. Tosi, S. Mottola, F. Capaccioni, D. Bockelee-Morvan, A. Longobardo, A. Raponi, G. Filacchione, G. Rinaldi, A. Rotundi, M. C. De Sanctis, M. Formisano, G. Magni
Summary: Through observations and simulations of the Rosetta mission, we have found that water production of comet 67P/Churyumov-Gerasimenko near the Sun is mainly from the dehydration of water-poor pebbles exposed by CO2-driven erosion. At larger distances from the Sun, water loss is dominated by self-cleaning of fallout deposits. Furthermore, the active area of the comet decreases as it moves away from the Sun.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Frederik Dhooghe, Johan De Keyser, Nora Haenni, Kathrin Altwegg, Gael Cessateur, Emmanuel Jehin, Romain Maggiolo, Martin Rubin, Peter Wurz
Summary: A full-mission analysis of Cl-bearing species in the coma of comet 67P/Churyumov-Gerasimenko detected by the Double Focusing Mass Spectrometer (DFMS) of Rosetta's ROSINA instrument revealed a stable chlorine isotopes ratio of 0.336, slightly higher than the standard mean ocean chloride value. The DFMS also indicated the presence of at least one additional chlorine-bearing species besides HCl, CH3Cl, and NH4Cl.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Bjorn J. R. Davidsson, Nalin H. Samarasinha, Davide Farnocchia, Pedro J. Gutierrez
Summary: The study investigates the European Space Agency's Rosetta/Philae mission to Comet 67P/Churyumov-Gerasimenko, aiming to understand the composition and evolution of the comet's nucleus materials.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Maria N. Drozdovskaya, Isaac R. H. G. I. Schroeder, Martin Rubin, Kathrin Altwegg, Ewine F. van Dishoeck, Beatrice M. Kulterer, Johan De Keyser, Stephen A. Fuselier, Michael Combi
Summary: Deuterated methanol provides insight into the chemical reactions forming deuterium-bearing molecules and the physicochemical history of celestial regions. The detection of mono- and di-deuterated methanol in a comet suggests formation through hydrogenation and substitution reactions, with a close relationship to D2O formation. The ratio of D-methanol/methanol in comets aligns with the composition in prestellar cores and low-mass protostellar regions, indicating a connection to the evolutionary phases of star formation.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
M. Sachse, D. Kappel, D. Tirsch, K. A. Otto
Summary: By using the discrete element method, this study simulated the formation of aeolian-like surface features on comet 67P/Churyumov-Gerasimenko and found that it involves both deposition of ejected material and surface erosion. The study also determined a set of parameters that produce reasonably realistic simulations.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
Selma Benseguane, Aurelie Guilbert-Lepoutre, Jeremie Lasue, Sebastien Besse, Cedric Leyrat, Arnaud Beth, Marc Costa Sitja, Bjorn Grieger, Maria Teresa Capria
Summary: This study aims to understand how cometary activity has affected the characteristics of pits and alcoves on the surface of 67P. The research findings suggest that progressive erosion cannot form pits and alcoves, and deep circular pits are potentially the least processed morphological features at the surface of 67P.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
O. Pinzon-Rodriguez, R. Marschall, S. -B. Gerig, C. Herny, J. S. Wu, N. Thomas
Summary: This study aims to investigate the factors influencing the generation of a comet's inner comae and model the gas activity distribution around its nuclei, with a focus on the effects of thermal conductivity and sub-surface ice sources on insolation-driven sublimation. The research found that thermal inertia and the depth of the sublimation front have a significant impact on the emission distribution of the gas flow field, with potential shifts in activity distribution and composition due to the presence of CO2.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
Marius Pfeifer, Jessica Agarwal, Matthias Schroeter
Summary: This study used data from the European Space Agency's Rosetta mission to track the motion of particles in image sequences and derive their velocities and accelerations. An algorithm was developed to locate the particles and reconstruct their tracks using the image sequences' pair-nature. The study found significant information about potential genuine particle tracks and obtained preliminary results on velocity, acceleration, and radius distributions.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
Y. -C. Cheng, D. Bockelee-Morvan, M. Roos-Serote, J. Crovisier, V. Debout, S. Erard, P. Drossart, C. Leyrat, F. Capaccioni, G. Filacchione, M. -L. Dubernet, T. Encrenaz
Summary: This study analyzed the spectra data of comet 67P and determined an ortho-to-para ratio (OPR) of water in the coma of the comet to be 2.94. The study also found that the OPR is strongly affected by opacity effects and shows an inverse correlation with the column density. The measured water rotational temperatures varied with altitude and heliocentric distance, indicating the influence of adiabatic cooling.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
N. Haenni, K. Altwegg, H. Balsiger, M. Combi, S. A. Fuselier, J. De Keyser, B. Pestoni, M. Rubin, S. F. Wampfler
Summary: By using DFMS data to derive the abundances of three cometary nitriles, the study conducted the first measurements of NCCN in a comet and found that neither NCCN nor the other two nitriles is sufficiently abundant to be a relevant alternative parent to CN.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
Pablo Lemos, Jessica Agarwal, Matthias Schroter
Summary: We developed a method to analyze images of the coma of comet 67P/Churyumov-Gerasimenko obtained using OSIRIS, the main imaging system on-board Rosetta. We applied this method to 105 images taken in 2015 and 2016, identifying more than 20,000 individual dust aggregates. The photometric analysis showed that the size of the aggregates decreases with increasing heliocentric distance, indicating a reduction in activity.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
D. Bockelee-Morvan, Gianrico Filacchione, Kathrin Altwegg, Eleonora Bianchi, Martin Bizzarro, Jurgen Blum, Lydie Bonal, Fabrizio Capaccioni, Mathieu Choukroun, Claudio Codella, Herve Cottin, Bjorn Davidsson, Maria Cristina De Sanctis, Maria N. Drozdovskaya, Cecile Engrand, Marina Galand, Carsten Guttler, Pierre Henri, Alain Herique, Stavro Ivanovski, Rosita Kokotanekova, Anny-Chantal Levasseur-Regourd, Kelly E. Miller, Alessandra Rotundi, Maria Schonbachler, Colin Snodgrass, Nicolas Thomas, Cecilia Tubiana, Stephan Ulamec, Jean-Baptiste Vincent
Summary: The AMBITION project aims to return the first cryogenically-stored sample of a cometary nucleus for the ESA Science Programme Voyage 2050. Comets are essential for understanding the formation of our Solar System, and researchers are still working on unanswered scientific questions that require laboratory analysis techniques only possible on Earth.
EXPERIMENTAL ASTRONOMY
(2022)
Article
Materials Science, Multidisciplinary
W. Dhaouadi, E. Marteau, H. Kolvenbach, M. Choukroun, J. L. Molaro, R. Hodyss, E. M. Schulson
Summary: This study presents a Discrete Element Model to describe the microstructure and evolution of porous planetary ice analogs. Sensitivity analysis and probabilistic calibration reveal the influence of particle-scale friction coefficient and cohesion energy density on the macroscopic properties of porous ice. The results shed light on the strengthening mechanism of porous ice and have implications for designing robust robotic systems.
Article
Astronomy & Astrophysics
Fernando Moreno, Daniel Guirado, Olga Munoz, Vladimir Zakharov, Stavro Ivanovski, Marco Fulle, Alessandra Rotundi, Elisa Frattin, Ivano Bertini
Summary: The dynamics of irregularly shaped particles in a cometary environment under the combined effect of gas drag and radiative forces and torques are investigated. It is found that the behavior of irregular particles is quite different from symmetric particles, and the radiative torques can be neglected compared to gas-driven torques at far distances.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
C. Gonzalez Diaz, S. Aparicio Secanellas, G. M. Munoz Caro, J. J. Anaya Velayos, H. Carrascosa, M. G. Hernandez, V. Munoz-Iglesias, A. Marcos-Fernandez, O. Prieto-Ballesteros, O. Witasse, R. Lorente, N. Altobelli
Summary: The study of thermal properties of frozen salt solutions representative of ice layers in Jovian moons is crucial to support the JUICE and Europa Clipper missions. A series of experiments were conducted to measure the thermal conductivity of specific salt solutions and spot phase changes in the frozen salt solutions.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Marco Fulle, M. Lazzarin, F. La Forgia, V. V. Zakharov, I Bertini, E. Mazzotta Epifani, E. Ammannito, A. Buzzoni, M. T. Capria, A. Carbognani, V Da Deppo, V Della Corte, S. Fiscale, E. Frattin, L. Inno, A. Migliorini, C. Pernechele, A. Rotundi, G. Sindoni, C. Tubiana, G. Milani, A. Aletti, P. Bacci, G. Baj, F. Bellini, E. Bryssinck, M. Di Grazia, M. Facchini, M. Feraco, E. Guido, R. Ligustri, F. Kugel, M. Maestripieri, D. Tirelli, A. Valvasori, C. Snodgrass, G. H. Jones
Summary: This study investigates the physical parameters driving cometary activity beyond Jupiter by observing dust tails at heliocentric distances larger than 4 au. The results show that the observed dust tails are consistent with the adopted activity model and that anisotropic dust ejection improves the tail fits. The findings also suggest cometary activity before the ejection of protocomets into the Oort cloud.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Mauro Ciarniello, Marco Fulle, Andrea Raponi, Gianrico Filacchione, Fabrizio Capaccioni, Alessandra Rotundi, Giovanna Rinaldi, Michelangelo Formisano, Gianfranco Magni, Federico Tosi, Maria Cristina De Sanctis, Maria Teresa Capria, Andrea Longobardo, Pierre Beck, Sonia Fornasier, David Kappel, Vito Mennella, Stefano Mottola, Batiste Rousseau, Gabriele Arnold
Summary: Comets evolve due to sublimation of ices embedded inside porous dust, which triggers dust emission, mass loss, mass redistribution, and surface modifications. Observations have shown puzzling water-ice-rich spots on the surface of comets, which are optically brighter and spectrally bluer than average surfaces, indicating macroscopic compositional dishomogeneities. The emergence of these spots is driven by CO2-ice sublimation that exposes water-ice-enriched blocks, which are then eroded by water-ice sublimation when exposed to sunlight.
Review
Astronomy & Astrophysics
Marco Fulle
Summary: Recent data and experiments suggest that dust accretion stops at pebble sizes in protoplanetary disks and pebbles split into water-rich and water-poor ones. Random mixtures of these pebbles play a crucial role in the diversity of comets.
Article
Astronomy & Astrophysics
A. Longobardo, T. Mannel, M. Kim, M. Fulle, A. Rotundi, V Della Corte, G. Rinaldi, J. Lasue, S. Merouane, H. Cottin, M. Ciarniello, F. Dirri, E. Palomba
Summary: This study combined data from two instruments onboard the European Space Agency's Rosetta mission to investigate the morphological and dynamical properties of dust ejected from the 67P/Churyumov-Gerasimenko comet. The results suggest that the compact dust particles detected by the MIDAS atomic force microscope are fragments of larger particles detected by the GIADA dust detector.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Bjorn J. R. Davidsson, F. Peter Schloerb, Sonia Fornasier, Nilda Oklay, Pedro J. Gutierrez, Bonnie J. Buratti, Artur B. Chmielewski, Samuel Gulkis, Mark D. Hofstadter, H. Uwe Keller, Holger Sierks, Carsten Guettler, Michael Kueppers, Hans Rickman, Mathieu Choukroun, Seungwon Lee, Emmanuel Lellouch, Anthony Lethuillier, Vania Da Deppo, Olivier Groussin, Ekkehard Kuehrt, Nicolas Thomas, Cecilia Tubiana, M. Ramy El-Maarry, Fiorangela La Forgia, Stefano Mottola, Maurizio Pajola
Summary: Research has shown that the depression in the Hapi region on Comet 67P/Churyumov-Gerasimenko was formed due to the influence of CO2 ice, providing constraints for previous observations. Additionally, it was found that solid-state greenhouse effect is produced when atmospheric gas particles settle down.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Chemistry, Multidisciplinary
Tuan H. Vu, Helen E. Maynard-Casely, Morgan L. Cable, Mathieu Choukroun, Michael J. Malaska, Robert Hodyss
Summary: This study explores the crystal structure and thermal behavior of 1,3-butadiene at cryogenic conditions. The results reveal significant anisotropic thermal expansion and a complex network of intermolecular interactions in its monoclinic structure. These findings contribute to our understanding of molecular solids on Titan's surface and their implications for physical and mechanical processes.
ACS EARTH AND SPACE CHEMISTRY
(2022)
Article
Astronomy & Astrophysics
V. V. Zakharov, A. Rotundi, D. Bockelee-Morvan, N. Y. Bykov, M. Fulle, N. Biver, V. Della Corte, A. V. Rodionov, S. L. Ivanovski
Summary: Under solar illumination, diverse ices on the cometary nucleus sublimate and form a gas coma containing multiple species. The gas production varies depending on the distance from the sun, resulting in a wide range of flow regimes. Therefore, it is essential to consider the kinetic effects on the gas flow and boundary conditions.
Article
Astronomy & Astrophysics
G. Cruz Mermy, F. Schmidt, F. Andrieu, T. Cornet, I. Belgacem, N. Altobelli
Summary: Europa's surface shows evidence of active resurfacing, potentially from either internal or external processes. Previous spectroscopic studies were limited by the lack of laboratory measurements, but recent access to optical constants and laboratory spectra of chemical compounds allows for testing the relevance of 15 potential endmembers. A fitting procedure using realistic modeling and Bayesian inference identifies sulfuric acid octahydrate and water ice as essential compounds.
Article
Astronomy & Astrophysics
Mauro Ciarniello, M. Fulle, F. Tosi, S. Mottola, F. Capaccioni, D. Bockelee-Morvan, A. Longobardo, A. Raponi, G. Filacchione, G. Rinaldi, A. Rotundi, M. C. De Sanctis, M. Formisano, G. Magni
Summary: Through observations and simulations of the Rosetta mission, we have found that water production of comet 67P/Churyumov-Gerasimenko near the Sun is mainly from the dehydration of water-poor pebbles exposed by CO2-driven erosion. At larger distances from the Sun, water loss is dominated by self-cleaning of fallout deposits. Furthermore, the active area of the comet decreases as it moves away from the Sun.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Multidisciplinary Sciences
Sascha Kempf, Nicolas Altobelli, Juergen Schmidt, Jeffrey N. Cuzzi, Paul R. Estrada, Ralf Srama
Summary: There is ongoing debate about whether Saturn's main rings are young or ancient. The rings are mostly composed of water-ice but are polluted by non-icy material. Continuous bombardment from micrometeoroids from outside the Saturnian system is the source of this pollution. By measuring the micrometeoroid flux into the Saturnian system, it is possible to estimate the rings' exposure time and infer their age. The final measurements by Cassini's Cosmic Dust Analyzer indicate a ring exposure time of less than or similar to 100 to 400 million years, supporting recent ring formation scenarios.
Article
Chemistry, Multidisciplinary
Ellen C. Czaplinski, Tuan H. Vu, Morgan L. Cable, Mathieu Choukroun, Michael J. Malaska, Robert Hodyss
Summary: Titan, Saturn's largest moon, has a rich variety of organic compounds that interact in its atmosphere and on its surface. This study demonstrates that the pyridine:acetylene co-crystal is stable under Titan-relevant conditions, suggesting its potential formation and preservation of geological and surface processes on Titan.
ACS EARTH AND SPACE CHEMISTRY
(2023)
