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
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
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
Herbert Gunell, Charlotte Goetz
Summary: This study successfully established a model for the electric fields within a low-activity comet by simulating both the waves and field structures far from the nucleus. The results showed that waves dominate the electric field at larger cometocentric distances, and the comet ion density is not spherically symmetric.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
B. Pestoni, K. Altwegg, V. Della Corte, N. Hanni, A. Longobardo, D. R. Mueller, A. Rotundi, M. Rubin, S. F. Wampfler
Summary: The Rosetta mission has enabled scientists to study a comet in unprecedented detail. Four instruments on the Rosetta orbiter have provided information on cometary dust particles. By comparing the data from two of these instruments, COSIMA and GIADA, it has been found that the particles detected by COSIMA are significantly correlated with the fluffy agglomerates detected by GIADA.
ASTRONOMY & ASTROPHYSICS
(2023)
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
F. L. Johansson, E. Vigren, J. H. Waite, K. Miller, A. Eriksson, N. J. T. Edberg, J. Dreyer
Summary: This study investigates the impact of gas molecule on the Cassini Langmuir probe measurements in the ionosphere of Saturn and provides explanations for several open questions raised by previous studies. It also reveals the highly structured ionosphere of Saturn and identifies water vapor as the dominant source of the signal.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
L. Bucciantini, P. Henri, P. Dazzi, G. Wattieaux, F. Lavorenti, X. Vallieres, J. Y. Brochot, F. Colin, M. C. Katrougkalou, G. Vengeons, T. Lecas, O. Le Duff
Summary: Mutual impedance experiments are diagnostic techniques used to identify plasma density and electron temperature. New instrumental modes are being developed to improve time resolution for future space missions. Chirp and multi-spectral modes are validated and found to provide measurements comparable to the reference frequency sweep mode.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2023)
Article
Astronomy & Astrophysics
B. Pestoni, K. Altwegg, V. Della Corte, N. Hanni, A. Longobardo, D. R. Mueller, A. Rotundi, M. Rubin, S. F. Wampfler
Summary: The Rosetta mission has enabled scientists to study a comet in unprecedented detail. Four instruments on the Rosetta orbiter have provided information on cometary dust particles. By comparing the data from two of these instruments, COSIMA and GIADA, it has been found that the particles detected by COSIMA are significantly correlated with the fluffy agglomerates detected by GIADA.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
Bruce T. Tsurutani, Rajkumar Hajra
Summary: This study examines the input and dissipation of solar wind energy in the magnetospheric-ionospheric systems during 17 supersubstorms triggered by interplanetary shocks. The research finds that shock compression significantly increases the southward component of the interplanetary magnetic field, leading to enhanced solar wind energy input through magnetic reconnection. This additional energy supplements the precursor energy input, resulting in high-intensity, long-duration supersubstorms.
ASTROPHYSICAL JOURNAL
(2023)
Review
Astronomy & Astrophysics
Peter Hoppe, Martin Rubin, Kathrin Altwegg
Summary: ESA's Rosetta mission has expanded the data sets on isotopic compositions of comets through its study of comet 67P/CG. By comparing these data with meteorite data, new insights into the formation conditions of small planetary bodies in the early Solar System have been gained.
SPACE SCIENCE REVIEWS
(2023)
Article
Astronomy & Astrophysics
David J. J. Andrews, Katerina Stergiopoulou, Laila Andersson, Anders I. E. Eriksson, Robert E. E. Ergun, Marcin Pilinski
Summary: Mars Express and MAVEN observations have revealed that the crustal magnetic fields on Mars affect the plasma in the ionosphere, leading to changes in plasma density and electron temperature. The study also found that there is a correlation between the crustal fields and electron temperatures at different altitudes. Furthermore, the influence of crustal fields on the ionosphere was found to vary on the nightside, contrary to previous studies.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2023)
Article
Astronomy & Astrophysics
Binbin Ni, Danny Summers, Zheng Xiang, Xiankang Dou, Bruce T. Tsurutani, Nigel P. Meredith, Junhu Dong, Lunjin Chen, Geoffrey D. Reeves, Xu Liu, Xin Tao, Xudong Gu, Xin Ma, Juan Yi, Song Fu, Wei Xu
Summary: Plasmaspheric hiss is a crucial electromagnetic wave mode in the Earth's Van Allen radiation belts. Measurements have shown that plasmaspheric hiss has banded signatures, with an upper band above 200 Hz, a lower band below 100 Hz, and a power gap in between. The occurrence of banded plasmaspheric hiss depends on geomagnetic and solar wind conditions. The waves may originate from both outside and inside the plasmasphere and shed new light on the radiation belts' evolution.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2023)
Article
Multidisciplinary Sciences
Ahmed Mahjoub, Kathrin Altwegg, Michael J. Poston, Martin Rubin, Robert Hodyss, Mathieu Choukroun, Bethany L. Ehlmann, Nora Hanni, Michael E. Brown, Jordana Blacksberg, John M. Eiler, Kevin P. Hand
Summary: The ROSINA instrument aboard the Rosetta mission has advanced our understanding of cometary material composition. By analyzing data from a dust event in September 2016, the study reveals the detection of large organo-sulfur species and an increase in the abundance of sulfurous species in the comet's coma. Laboratory simulations further suggest that these materials may have formed from the irradiation of mixed ices containing H2S. This study emphasizes the significance of sulfur chemistry in cometary and precometary materials, and proposes the possibility of characterizing organosulfur materials in other comets and small icy bodies using the James Webb Space Telescope.
Article
Astronomy & Astrophysics
N. Haenni, K. Altwegg, D. Baklouti, M. Combi, S. A. Fuselier, J. De Keyser, D. R. Mueller, M. Rubin, S. F. Wampfler
Summary: The complexity of terrestrial biomolecules has led to a search for complex organic molecules in the interstellar medium. The study focused on the analysis of O-bearing organic volatiles in a comet and compared the results with molecules found in the interstellar medium, other comets, and meteorites. The study discovered abundant O-bearing heterocycles and various other molecule classes in the comet, providing insights into the chemical complexity of space.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
Z. M. Lewis, A. Beth, K. Altwegg, M. Galand, C. Goetz, K. Heritier, L. O'Rourke, M. Rubin, P. Stephenson
Summary: The European Space Agency/Rosetta mission analyzed the ion composition in the coma of comet 67P/C-G and found high proton affinity species, particularly NH4+, indicating a high level of ion-neutral chemistry. The increased comet outgassing around perihelion led to more detections of NH4+ and other protonated HPA species, suggesting complex ion-neutral chemistry. The low magnetic field strength associated with the diamagnetic cavity was linked to higher NH4+ counts, indicating different transport dynamics inside and outside the diamagnetic cavity.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
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
S. E. Milan, M. K. Mooney, G. E. Bower, M. G. G. T. Taylor, L. J. Paxton, I. Dandouras, A. N. Fazakerley, C. M. Carr, B. J. Anderson, S. K. Vines
Summary: We investigated a 15-day period in October 2011 and found weak cusp-aligned arc (CAA) emissions in the polar regions when the interplanetary magnetic field (IMF) clock angle was small. Simultaneous observations of ions and electrons showed that dense plasma was observed even far from the equatorial plane of the tail. We interpret the observations as evidence of trapped plasma on closed field lines, suggesting that the magnetosphere was almost entirely closed during these periods.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2023)
Review
Astronomy & Astrophysics
Andrea Longobardo, Minjae Kim, Boris Pestoni, Mauro Ciarniello, Giovanna Rinaldi, Stavro Ivanovski, Fabrizio Dirri, Marco Fulle, Vincenzo Della Corte, Alessandra Rotundi, Martin Rubin
Summary: This study summarizes the findings of the ESA/Rosetta mission on the Jupiter Family Comet 67P/Churyumov-Gerasimenko. The data collected from instruments onboard the Rosetta orbiter, along with numerical models and experimental work, have provided important insights into cometary activity mechanisms. The study reveals correlations between dust ejection and solar illumination, as well as the dominance of water sublimation during the perihelion phase. The comparison of dust fluxes and particle sizes also suggests a link between dust morphology and ejection speed.
Article
Chemistry, Physical
Murthy S. Gudipati, Benjamin Fleury, Robert Wagner, Bryana L. Henderson, Kathrin Altwegg, Martin Rubin
Summary: Ice is an important component of astrophysical environments and can coexist with complex organic matter. It is believed that primordial ice brought the molecules of life to Earth and kickstarted the origin of life. Laboratory experimental studies combined with telescopic observations can provide deeper insight into the processes occurring in these environments. In this study, simultaneous mass spectrometric and infrared spectroscopic investigations were conducted to understand the behavior of molecular ice mixtures at different temperatures and its implications for interpreting observational data.
FARADAY DISCUSSIONS
(2023)
Article
Engineering, Aerospace
T. M. Ho, E. Kuehrt, X. J. Zhang, U. Auster, J. Biele, M. Grott, J. T. Grundmann, H. Heg, A. Hoerdt, J. C. Huang, T. Mai, S. Mottola, K. Otto, D. Plettemeierj, L. Qin, M. Rubin, N. Schmitz, S. Ulamec, J. B. Vincent
Summary: CALICUT, a nanolander, is proposed for an Asteroid Exploration Mission by a joint European-Chinese team. It is designed to operate on an active asteroid in the main belt, with mobility and autonomy capabilities for at least 6 weeks of data collection. The nanolander carries four scientific instruments to provide unique measurements on the surface.
