We present a novel approach to reconcile fireball analysis methods by integrating the purely dynamical alpha-beta model with traditional photometric constraints. Utilizing three key trajectory points—beginning, peak brightness, and terminal—and photometric mass, we perform a fit to reconstruct atmospheric flight parameters, including velocity profiles, initial and terminal masses, and meteoroid bulk density. We address this classical inverse problem—identifying the optimal fit to observational data using minimal input—by employing a metaheuristic global optimization algorithm based on Differential Evolution. The analysis assesses compatibility with pre-existing PE classifications and evaluates the method's potential for providing robust estimates. This approach aims to enhance our knowledge of meteoroid properties and support the creation of reliable and adaptable methods for fireball characterization. Such methods will enable the automated classification of meteor events, improving the recovery of fresh meteorites and strengthening our capacity to monitor and address potential hazards posed by near-Earth objects.
How to cite: Peña-Asensio, E. and Gritsevich, M.: Unified Framework for Estimating Ballistic Coefficient, Mass Loss, and Bulk Density in Meteor Dataset Analysis, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-19730, https://doi.org/10.5194/egusphere-egu25-19730, 2025.
Ground-based meteor radars detect the plasma streaks produced when meteoroids ablate in our atmosphere. However they are limited to detecting particles that produce a sufficient amount of plasma within the instrument’s field-of-view, and thus most of the meteoroid’s trajectory remains undetected. Previous work by Dawkins et al. (2023) and Stober et al. (2023) utilised new polarisation measurements made by the Southern Argentina Agile Meteor Radar Orbital System (SAAMER-OS, 53.8oS, 67.8oW, Janches et al., 2019), in conjunction with two state-of-the-art models, in order to determine the pre-atmosphere dynamical characteristics (mass, velocity) of the detected particles before they suffered any significant ablation or deceleration. Subsequent work has focused on automating this methodology, to allow us to determine the pre-atmosphere characteristics for all meteoric particles detected by SAAMER-OS. In this work we describe this background methodology and how it can be applied to different facets of atmospheric and astronomical research, including (1) how we can characterise the astronomical sources detected at SAAMER-OS through time (mass and velocities), (2) detections of new meteor showers, (3) to understand the mass distribution function of particles that enter the top of the atmosphere, and (4) variability of atmospheric neutral densities in the Earth’s upper atmosphere.
How to cite: Dawkins, E., Janches, D., Stober, G., Carrillo-Sánchez, J. D., Weryk, R., Hormaechea, J. L., and Plane, J.: Detecting meteoroids with the Southern Argentina Agile Meteor Radar Orbital System (SAAMER-OS): applications for atmospheric and astronomical research., EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-12565, https://doi.org/10.5194/egusphere-egu25-12565, 2025.
The Meteorite Center at the Sharjah Academy for Astronomy, Space Science and Technology (SAASST) in the United Arab Emirates houses a diverse collection of 8,000 specimens, including 805 meteorites of various types, such as stony, iron, and iron-stony meteorites. These specimens, sourced from various locations worldwide, include meteorites with parent bodies such as the Moon and Mars, providing insights into the rich diversity of meteorite subdivisions and their origins. This collection is the only one of its kind in the Gulf region, making it a distinctive asset within the Middle East and North Africa (MENA) region and a unique resource for studying the processes that shaped our solar system.
This research paper aims to explore the diversity within the meteorite collection and conduct a statistical analysis to fully utilize its potential. It will discuss the physical and chemical properties of the different meteorite types and the differences between them, using advanced techniques such as X-ray Fluorescence (XRF), X-ray Diffraction (XRD), and Scanning Electron Microscopy (SEM). These methods will provide detailed insights into the elemental composition, mineral phases, and microstructural characteristics of the specimens, allowing for a deeper understanding of their formation processes and origins. The results are expected to reveal variations in mineralogical composition and structural features across different meteorite types. Additionally, the data will be compared with the retrieval locations of the meteorites to trends that may influence their composition and properties.
How to cite: Odat, S., Alzaouri, A., Batarfi, N., Shariff, M., Manousakis, A., and Al Naimiy, H.: Exploring Meteorite Diversity: A Statistical and Compositional Review of the Meteorites in the SAASST Collection , EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-16419, https://doi.org/10.5194/egusphere-egu25-16419, 2025.
Numerical modelling is crucial for understanding micrometeorite atmospheric entry, yet most existing models treat cosmic dust grains as chemically inert, anhydrous particles. However, empirical studies of micrometeorites recovered on Earth reveal that hydrated, phyllosilicate-bearing particles dominate the cosmic dust flux at size fractions above ~100 µm. The thermal decomposition of phyllosilicates is expected to play a significant role in reducing peak temperatures during entry, thereby increasing the chances of their survival to the Earth's surface, but this process is currently not incorporated in most models. To address this, we developed the first numerical model simulating the thermal behaviour of phyllosilicate-dominated micrometeorites during atmospheric entry. Building on the Love and Brownlee model, we include both sub-solidus decomposition and supra-solidus evaporation processes, as constrained by thermogravimetric analysis data from heating experiments on cronstedtite and saponite, the main phyllosilicate species in CM, CR and CI chondrites. Three particle-specific factors govern decomposition behaviour of phyllosilicate-dominated micrometeorites during entry: (1) grain density, (2) enthalpy of dehydration, and (3) the volatile budget. The sub-solidus loss of water helps reduce peak temperatures in phyllosilicate micrometeorites, but the effect is relatively modest compared to anhydrous olivine. Furthermore, saponite experiences lower peak temperatures than cronstedtite, despite cronstedtite having a higher enthalpy of decomposition and a larger volatile budget. This effect is attributed to cronstedtite’s higher density, which leads to more intense thermal processing, resulting in thermal histories that resemble those of olivine-dominated micrometeorites. Since CI chondrites contain saponite, CI-like micrometeorites are more likely to survive entry without melting relative to CM-like micrometeorites under the same conditions. Finally, our results suggest that hydrated micrometeorites ~50 µm are more likely to survive atmospheric entry without loss of water only in grazing scenarios (entry angles >80°, where entry angle is measured from zero with respect to the zenith). This explains the rarity of hydrated, fine-grained micrometeorites containing intact crystalline phyllosilicates, as observed in petrographic studies of unmelted cosmic dust.
How to cite: Micca Longo, G., Suttle, M. D., and Longo, S.: Atmospheric entry of hydrated, phyllosilicate-rich micrometeorites: experiment and numerical model, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-3112, https://doi.org/10.5194/egusphere-egu25-3112, 2025.
The inner solar system experienced a period of intense cometary bombardment following a dynamical instability among the giant planets, which occurred after the dispersal of the gas disk. Vesta, the second-largest asteroid in the main asteroid belt, provides a unique opportunity to study this period, as it is believed to have fully differentiated before gas disk dispersal. This differentiation implies that Vesta's crust, which is represented today by HED meteorites, could have recorded evidence of cometary impacts.
To investigate the extent of cometary contributions to Vesta’s crust, we adopted an interdisciplinary approach combining several methodologies including noble gas mass spectrometry measurements, N-body simulations, collision rate calculations, and impact simulations.
Our results show that Vesta likely experienced numerous impacts with large comets. Despite this, we find no xenon cometary signature in HED meteorites. This apparent contradiction can be explained by the fact that cometary impacts were at high speeds and Vesta’s weak gravitational attraction made it incapable of retaining cometary material. Consequently, smaller asteroids, with even weaker gravity, are even less likely to retain material from cometary collisions. Thus, the detection of cometary xenon in samples returned from an asteroid by a space mission would serve as a smoking gun, pointing to co-formation in a shared source region with comets, and a later implantation into the asteroid belt.
How to cite: Joiret, S., Avice, G., Ferrière, L., Leinhardt, Z., Lock, S., Mechineau, A., and Raymond, S.: Asteroids fail to retain cometary impact signatures, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-2571, https://doi.org/10.5194/egusphere-egu25-2571, 2025.
NH-rich compounds have been detected on Ceres (Sanctis et al., 2015), comet 67P (Poch et al., 2020) and possibly other asteroids (Rivikin et al., 2022), based on the 3.1 µm absorption in their infrared reflectance spectrum. This feature has never been found among the meteorite collections but recently reported on the returned Ryugu sample (Pilorget et al., 2022). Studying these compounds can help us understand the parent bodies evolution and the volatiles delivery within the Solar System. In 2023, NASA’s OSIRIS-REx mission returned ~120 g sample from the primitive asteroid Bennu (Lauretta et al., 2024). Preliminary analyses showed that Bennu samples share many chemical and mineralogical similarities with Ryugu samples. Here we search for the NH-rich compounds in the Bennu samples and compare them with Ryugu samples.
Thanks to an agreement between NASA and JAXA, ~0.6 g of Bennu samples was delivered to the Extraterrestrial Sample Curation Center (ESCuC) of JAXA (Sagamihara, Japan). They are stored and measured under controlled environment (N2 purged) to avoid terrestrial contamination and alteration (Fukai et al., 2023). Samples are composed of 5 bulks, from which aggregate samples and mm-sized grains were extracted after a first campaign of analyses. Here we combined observations performed by the infrared-hyperspectral microscope MicrOmega (22.5 µm pixel size, 256x256 pixel, FOV 5x5 mm, spectral range 0.99-3.65 µm), a micro-FTIR spectrometer (single pixel, ~50-100 µm FOV, spectral range 2-13 µm) and a LEICA optical microscope (Bibring et al., 2017; Pilorget et al., 2022; Fukai et al., 2023). We have specifically searched for regions of interest (ROIs) with strong absorption around both 2.7 µm (OH) and 3.06 µm (NH).
We have detected 8 NH-bearing ROIs (by 23rd December 2024), relatively rare compared to other minor phases such as carbonates. Their sizes vary from ~100 µm to ~1 mm, with different morphology, from rounded to elongated/irregular. For example, one of the ROIs shows a vein-liked shape, another one looks like a thin layer coating on the matrix material. The corresponding area in visible microscope images is often yellowish in color. In terms of brightness, they are generally much brighter in reflectance (~5-15%) than the surrounding matrix materials (2~3%). All the ROIs show much deeper (~40%) absorption around 2.7 µm than that of matrix materials (~10 %), which is similar to that of Ryugu ROIs if we average all the ROIs spectra for both datasets. Their band position is ~2.72 µm, similar to the matrix materials and those of Ryugu sample. All the ROIs also show deep absorption around 3.06 µm (~15%). The FTIR spectra are consistent with MicrOmega data in the overlapping wavelength region (2.0-3.6 µm). In the longer wavelength, these ROIs generally show bands around 6 µm (~1650 cm-1, water molecule), around 7 µm (~1430 cm-1, NH4+), and around 10 µm (~1020 cm-1, Si-O).
These results show that ammonium (NH4+) is present in Bennu samples, with a possible connection with phyllosilicates. Importantly, we also observed similarities with NH-rich areas detected in Ryugu samples, thanks to the measurements on both collections by MicrOmega.
How to cite: Jiang, T., Pilorget, C., Baklouti, D., Loizeau, D., Hatakeda, K., Abe, M., Bibring, J.-P., Enokido, Y., Fukai, R., Kawasaki, S., Lantz, C., Miyazaki, A., Nardelli, L., Nishimura, M., Okada, T., Riu, L., Sheppard, R. Y., Tahara, R., Usui, T., and Yada, T. and the ISAS-IAS MicrOmega/Curation team: Detection of NH-rich compounds in Bennu pristine samples via IR characterization at JAXA Curation Center and comparison with Ryugu, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-16881, https://doi.org/10.5194/egusphere-egu25-16881, 2025.
Isotopic ratios of water can be used to trace the origin of water in our oceans, and comets have been proposed as a potential source. But cometary comae are a mixture of gas and ice-covered dust, and processing on the surface and in the coma change the composition of ice on dust grains relative to that of the nucleus. As the ice on dust grains sublimates, the local coma composition changes. Rosetta coma composition observations of 67P/Churyumov-Gerasimenko (67P/C-G) are local coma measurements, and thus are highly sensitive to being influenced by ice sublimating from dust near the spacecraft.
Previously, the D/H of 67P/C-G was reported to be one of the highest D/H values for a comet. Such a high D/H would require that 67P/C-G formed very far away from the sun. However, this does not agree with all measurements made in other Jupiter Family Comets (JFCs) which have lower D/H ratios. Also, the comet should also have a lot more CO and N2 than has been observed because these ices also form at large distances from the Sun. Although attempts have been made to address these discrepancy by arguing that comet 67P/C-G is made up of primordial materials from before the solar system formed, questions continued to arise about how a JFC could have such a high D/H. We have developed a new technique for evaluating the Rosetta observations that provides greater reliability in isolating the signal of HDO while providing more accurate estimates of the uncertainties. This method is also faster to apply than linear least squares methods, allowing us to evaluate more than 16,000 measurements of D/H throughout the Rosetta mission. Of these measurements, more than 4000 water isotope measurements had sufficient signal to noise to study variation of D/H over the full mission. These data show that dust dramatically increases local D/H. The isotope ratio measured at a distance from the nucleus where the spacecraft is away from any ice sublimating from dust is close to terrestrial, like that of other JFCs. This lower D/H has implications for understanding comet formation and the role of comets in delivering water to Earth.
How to cite: Mandt, K., Lustig-Yaeger, J., Luspay-Kuti, A., Wurz, P., Bodewits, D., Fuselier, S., Mousis, O., Petrinic, S., and Trattner, K.: A nearly terrestrial D/H for comet 67P/Churyumov-Gerasimenko, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-11674, https://doi.org/10.5194/egusphere-egu25-11674, 2025.
The composition and structure of comets provide key insights into planetary formation processes and the conditions present in the early Solar System. Especially dynamically new comets (DNC) with a long orbiting period have remained mostly untouched and are assumed to have preserved their structure for billions of years. The findings from previous missions like Stardust or Rosetta/Philae have indicated that comets are highly porous, and the water ice is mostly covered with dust (Groussin et. al. 2019). However, these findings were mostly conducted on larger scales, and little is known about the structure at smaller scales. Resolving the sub-surface structure on a sub-centimeter level could be valuable to challenge planetary formation theories.
Further in-situ exploration is required to discover the relationship between non-volatile and volatile materials. Since water ice is mainly transparent to THz frequencies (Ioppolo et. al. 2014), and the spatial resolution achievable at these frequencies is on the millimeter scale, we explore the application of in-situ THz time-domain spectroscopy to analyze the sub-surface structure of comets. THz spectroscopy offers higher spatial resolution than ground-penetrating radar, while still being capable to penetrate the upper surface layers. While THz spectroscopy has a lower spatial resolution compared to infrared (IR) spectroscopy, IR cannot penetrate the surface, limiting its applicability for subsurface studies. Moreover, the fingerprint absorption spectrum of water vapor enables THz spectroscopy to analyze sublimation above the surface. Investigating the activity of comets further provides valuable insights into the subsurface structure.
Our novel laboratory setup COCoNuT (Characteristic Observation of Cometary Nuclei using THz-spectroscopy) provides the capabilities to simulate the conditions we expect to encounter on a comet and perform proof-of-concept measurements with a commercial spectrometer (Stöckli et. al. in revision).
We present our first measurements with cometary analogue samples composed of dust and ice.
Groussin, O., Attree, N., Brouet, Y. et al. The Thermal, Mechanical, Structural, and Dielectric Properties of Cometary Nuclei After Rosetta. Space Sci Rev 215, 29 (2019).
Ioppolo, S., McGuire, B. A., Allodi, M. A., and Blake, G. A. (2014). THz and mid-IR spectroscopy of interstellar ice analogs: methyl and carboxylic acid groups. Faraday Discuss., 168:461–484.
Stöckli, L. L., Brändli, M., Piazza, D., Ottersberg, R., Pommerol, A., Murk, A., Thomas, N. (2025). Design and Commissioning of a THz Time Domain Spectro-Goniometer in a Cryogenic Comet Simulation Chamber. Rev. of Sci. Instruments, in revision.
How to cite: Stöckli, L., Ottersberg, R., Belousov, D., Pommerol, A., and Thomas, N.: Insights into Resolving the Sub-surface Structure of Cometary Analogues using THz Spectroscopy, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-11684, https://doi.org/10.5194/egusphere-egu25-11684, 2025.
Sample return missions provide the ultimate ground truth for interpretation of remote sensing data and enable an unprecedented level of analysis compared to in-situ instruments. In response to the explosion of interest in this field in recent years the German Aerospace Center (DLR) in Berlin is constructing a Sample Analysis Laboratory (SAL) for the analysis and curation of returned samples in close cooperation with the Museum für Naturkunde (MfN), and in collaboration with colleagues at NASA and JAXA. Key topics to which SAL will contribute are the formation and evolution of planetary bodies, detection of organics and the history of hydration, oxidation and alteration of samples, as well as possible traces or signs of extinct life.
The laboratory will provide a cleanroom environment of approximately 80 m2, with a space below of similar footprint housing the technical equipment (vacuum pumps, water cooling etc.). The major analytical instruments have already been purchased for SAL: a JEOL iHP200F Field Emission Electron Microprobe Analyzer (FE-EMPA), a JEOL JSM-IT800 Field Emission Scanning Electron Microscope (FEG-SEM) and a Malvern Panalytical Empyrean X-ray Diffraction (XRD) system. These instruments have sealed transport containers allowing transport of sensitive material under controlled atmospheres. In addition, two ISO-5 level, N2-purged, glove boxes are planned for storage and sample manipulation and preparation.
The complementary range of instrumentation in a cleanroom environment with controlled sample storage and preparation glove boxes, in addition to the existing PSL, PASLAB and Raman laboratory spectroscopy facilities on site, constitute a strong basis for the long-term goal of establishing a European center for extraterrestrial sample curation and analysis in Berlin. The SAL cleanroom construction is planned to be finished in the summer of 2025, with operation and commissioning due to be well under way by autumn. This contribution will give an overview of the DLR Sample Analysis Laboratory, the time plan and major goals for the coming years.
Keywords: Extraterrestrial samples, sample return, meteorites, laboratory measurements.
How to cite: Garland, S., Helbert, J., Van den Neucker, A., Bonato, E., Greshake, A., Maturilli, A., Alemanno, G., Hecht, L., Adeli, S., Büttner, I., and Rauer, H.: The sample analysis laboratory (SAL) at the German Aerospace Center (DLR) Berlin – A cutting edge laboratory for extraterrestrial material analysis, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-21780, https://doi.org/10.5194/egusphere-egu25-21780, 2025.
Introduction: Calcium-aluminum-rich inclusions (CAIs) represent the earliest known solid materials to have formed in the Solar System, offering critical insights into the initial stages of the solar accretion disk's evolution. [1]. An important unresolved challenge in reconstructing material transport and flow processes in the evolving solar accretion disk is understanding how CAIs migrated and were stored during the period of up to 1 million years between their formation near the protosun and their incorporation into carbonaceous chondrites in the outer Solar System. The transport of CAIs to the outer Solar System may have either occurred through movement within the disk or via ballistic trajectories above the disk driven by X-winds. Their storage could have taken place within a pre-existing CAI parent body or in pressure bumps located in the distant regions of the solar accretion disk. In certain scenarios, CAIs were likely exposed to cosmic rays from the Sun or the galaxy. This project aims to investigate the cosmic ray-induced irradiation effects present in CAIs from carbonaceous chondrites.
Methods: Following our earlier study [2] demonstrating that X-ray scanning does not affect the noble gas budget, we performed X-ray scans of our samples to locate CAIs. The scans were conducted using a multiscale nanoCT laboratory system SkyScan 2214 housed at the Institute of Anatomy, University of Bern. Based on the CT data, the samples were precisely sectioned at the Natural History Museum of Bern. The CAIs were subsequently analyzed for their chemical composition using SEM at the Institute of Geological Sciences, University of Bern. We extracted fine-grained and coarse-grained samples using microscopy, micro-drilling, and dental tools. Finally, the samples were analyzed for their isotopic compositions of He, Ne, Ar, and Kr using a sector field mass spectrometer at the University of Bern.
Results and Discussion:
The results so far indicate that the studied CAIs now show clear indications of pre-accretionary irradiation effects. Since the conclusion is solely based on CAIs from the CV3 chondrite Allende, we are currently extending the database to include CAIs from other carbonaceous chondrite types.
References: [1] Krot A. N. et al. (1995) Meteoritics 30, 530-531 [2] Ghaznavi P. et al. (2023) Meteoritics & Planetary Science, 58, Nr 6, 897–900
How to cite: Ghaznavi, P., Berger, A., Haberthür, D., Hlushchuk, R., Khoma, O.-Z., Hofmann, B., and Leya, I.: Investigating Pre-Irradiation Effects in CAIs from Carbonaceous Chondrites, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-15909, https://doi.org/10.5194/egusphere-egu25-15909, 2025.
Water ice aggregates play a crucial role in the formation of solar system planets. The growth of water ice are considered a driving force for planetesimal formation, particularly in the outer regions where temperatures are low enough for water to freeze. An investigation to the collisional behavior of aggregates made of μm-sized water ice particles under microgravity will contribute to understanding the growth of planetesimals and formation of ice giants.
We constructed a cryo-vacuum drop tower to simulate the growth and collisional evolution of ice aggregates under microgravity. This drop tower enables a systematic process for preparing ice aggregates through sedimentary growth and supports collision experiments at velocities ranging from 0.2 m/s to 0.5 m/s. The experimental scheme in this work aims to determine the physical properties of ice aggregates, such as velocity thresholds, sticking probabilities, and collision parameters.
We designed a multifunctional vacuum drop tower with a height of 3.6 m and an inner diameter of 1 m. The experimental devices connected to the top cover of the drop tower can be flexibly replaced or customized according to specific requirement of each experiment. For the ice aggregates collision experiments, we developed a cylindrical sample chamber where the temperature can be maintained below 130K by using a refrigerator. The chamber, attached to the top cover, includes two holders functioning as the release mechanism, each with a crystallization ladle at its end. Inside the chamber, 𝜇m-sized water droplets are introduced, and random ballistic deposition (RBD) aggregates are formed on the crystallization ladles. The sedimentary growth process is monitored through an observation window located at the top of the sample chamber. After preparing the aggregates, the internal pressure of the drop tower is reduced to below 1 Pa. The release mechanism then sequentially releases two samples, and the samples collide at a settled relative velocity during free fall. Two high-speed cameras mounted on the outer rail of the drop tower will be released simultaneously and record the entire collision process.
Compared to previous experimental studies, our work offers several advantages. The drop tower integrates sample preparation and collision experiment, enabling in-suit preparation and release of aggregates. Additionally, a refrigerator is used for colling instead of liquid nitrogen, providing safer and more reliable refrigeration. High-speed cameras are mounted on rails, ensuring a more stable observation platform. We plan to conduct collision experiments to investigate the physical properties and growth mechanisms of water ice aggregates.
We will present the design and techniques of the cryo-vacuum drop tower and demonstrate its capabilities.
How to cite: Wu, Y., Zhang, X., Xiao, Y., and Yu, Y.: Design of a cryo-vacuum drop tower for simulating water ice aggregates collisions in planetesimal formation, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-5395, https://doi.org/10.5194/egusphere-egu25-5395, 2025.
Asteroid (99942) Apophis will make a close encounter with Earth at a perigee distance ~38,000 km on April 13, 2029, offering a unique opportunity to advance planetary science, deflection technology, and public engagement. This rare event enables real-time observation of the tidal interaction between a hundred-meter-scale asteroid and a planet, especially the geophysical processes occurring on the Asteroid’s regolith layer, which promises rich scientific rewards to planetary science researchers. On the other hand, as a potentially hazardous asteroid, Apophis presents a rare opportunity to test various concepts in planetary defense, such as the necessity, possibility, and technical challenges of implementing rapid-response reconnaissance missions. Therefore, this encounter has been the focus of studies on asteroid missions for recent years. Here we present a concept that utilizes multiple flybys of Apophis with a swarm of CubeSats. This concept aims to determine the basic properties of Apophis, including its mass, surface topography, spin status, and internal structure during its close encounter. Multiple CubeSats will be launched either through dedicated missions or as secondary payloads on other launches, either all at once or in stages, to conduct a series of flybys simultaneously or sequentially. The CubeSats can take similar or different payloads to investigate the target in synergy. In addition to performing multi-spectral optical measurements, the CubeSats Swarm can also achieve stereoscopic imaging and morphological analysis of the asteroid surface, or pricisely measure the gravitional field through highly sensitive microwave ranging instruments, which will provide critical constraints for the studies of Apophis interior structure and its defense strategy. Once the science goals are defined and prioritized, one can define a threshold mission, a baseline mission, and an enhanced mission, each corresponding to specific science priority, risk profile, and cost profile. This framework will provide flexibility, versatility, expandability, and potential low cost to allow for rapid mission integration by accommodating the potentially fast-evolving mission concept development and implementations. It will also allow for contributions from various partners to expand the science and participation of a mission concept. On the other hand, the coordination and communication between various CubeSats and mission components could increase the complexity of both implementation and scientific operations of the mission. Our future research will identify the pros and cons of this mission framework in the context of the 2029 Apophis exploration.
How to cite: Yu, Y., Li, J.-Y., Shi, X., Cheng, B., Zhang, N., Song, Z., and Ye, M.: Apophis Recon Swarm (ARS): Rapid-response Multi-flyby mission to Apophis using a CubeSats Swarm, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-14120, https://doi.org/10.5194/egusphere-egu25-14120, 2025.
In this study, we investigate the spatial and density distribution of zodiacal cloud dust in the inner solar system, with the focus being on Mercury's orbit and the formation and persistence of the circumsolar dust ring discovered in 2018 in the immediate vicinity of the Sun. Previous knowledge of Mercury's orbital environment suggests that, due to its proximity to the Sun and hence its extremely high perturbation effects, this environment may not contain matter in the longer term. This picture seems to have become more uncertain. In our model, we have considered the constrained three-body problem of the Sun-Mercury system along the Lagrangian libration points, which due to the degree of stability and the 1:1 mean motion resonance and the continuous perturbative effects of the perturbed dust particle motion within the stable region we assumed a horseshoe orbit. According to our model, the horseshoe orbit undergoes a strong deformation due to the proximity of the Sun at the near-solar boundary of the stable region, where the Poynting-Robertson effect causes dust particles of different grain sizes to continuously fall out of the stable region and spiral into the Sun. To represent the fate of the different grain sizes, a circumsolar dust ring was set up in three scenarios, in all three of which a smaller compact ring of larger grains appeared.
Using comet 67P/Churyumov-Gerasimenko as a mass reference, the number of comets needed to fill the toroidal volume of the orbit of Mercury and the time scale required to do so were quantified. As a final result, our model predicts that the instrumentally discovered circumsolar dust ring is distributed along a highly deformed horseshoe track, which can persist in a continuously replenished dynamical system such that the dust grains that constitute it are replaced on a century-to-millennium scale.
How to cite: Péterfy, S. and Székely, B.: Dynamical horseshoe orbit as the explanation to a circumsolar dust ring in the neighbourhood of Mercury? , EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-12086, https://doi.org/10.5194/egusphere-egu25-12086, 2025.
Saturn’s narrow, clumpy F ring is a region disturbed by chaotic orbital dynamics. We therefore model it as a stochastic process (specifically, a finite Markov chain). The ring appears dominated by dust in camera images, but the main mass of this ring resides in a core of elongated clumps called kittens, observed by ring occultations. Cassini UVIS sees such features about 1/3 of the time, the same frequency as the radio occultation detections of the F ring core; both have similar size distribution. We model the F ring core as kittens (transient aggregates with size 100 m < dr < 3 km), including perturbations due to Prometheus encounters, resonance confinement, and mutual collisions. We solve for the stationary state. Without confinement, the probability of detecting the kittens is uniformly distributed. With corotation resonance confinement [1], the stationary state is sharply peaked, consistent with the longitudinal distribution of detections of the F ring by radio occultation. Considering shepherding alone, the Cassini radio observations are nonetheless better fit by the non-confinement stationary distribution, and even better by just 20% confined. We find acceptable fits for fractions up to 70% of the clumps shepherded in the 109:110 Prometheus CER. This alternative combines with the explanation of [1] to conclude that some fraction of the population, or some fraction of the time, the F ring is shepherded by Prometheus. We explain the persistence of the F ring due to negative diffusion [2][3], where the ring is confined by Prometheus aligning particle phases. We include the negative diffusion in the Markov chain using an Ehrenfest diffusion model [4]. A small asymmetry explains the distribution in resonant argument of the radio occultation detections. In all cases, Prometheus is the agent for confinement. The F ring is shepherded by a combination of a Prometheus corotation and a Lindblad resonance that yields non-isotropic collisions: For combined model: Shepherded fraction < 0.2 ; Diffusion asymmetry factor F = 0.48 - 0.50.In all cases, ‘negative diffusion’ can maintain the longitudinal distribution either alone, or in combination with shepherding, if the mean motion resonance coincides with the true core of the F ring.
- Cuzzi, JN al. (2024). Saturn’s F ring is intermittently shepherded by Prometheus.
Science, 10 May 2024. - Lewis, MC al. (2011). Negative diffusion in planetary rings with a nearby moon. Icarus 213, 201.
- Sickafoose, AA and Lewis, MC (2024). Numerical simulations of Chariklo’s rings with a resonant perturber. Planetary Science Journal, February 2024.
- Feller, W (1968). An Introduction to Probability. Wiley.
How to cite: Esposito, L. W. and AlRebdi, A.: Saturn’s F Ring is Confined by Prometheus and Negative Diffusion, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-7119, https://doi.org/10.5194/egusphere-egu25-7119, 2025.
The Venetia Burney Student Dust Counter (SDC) aboard New Horizons provides unique insights into dust dynamics beyond 17 AU and extending through the Kuiper Belt. SDC’s ability to detect dust grains larger than 10−12 grams allows it to map dust size and density distributions along the New Horizons’ flight path, presenting unparalleled data up to 61 AU. Recent SDC observations reveal fluxes two to three times higher than earlier models predicted beyond 45 AU. These findings, in conjunction with modern simulations, suggest that the composition of dust grains—ranging from refractory silicates to volatile ices—plays a more significant role in the outer solar system dust density than previously considered, with icy grains demonstrating unique outward migration due to erosion rates that far exceed those of refractory grains.
We present updated dust flux measurements out to 61 AU, detailed comparisons with new numerical simulations of pure ice and pure refractory grains, and preliminary results of mixed-composition grains. The results underscore the importance of continued efforts to model mixed refractory-volatile grains to accurately interpret the Kuiper Belt’s dust production and transport mechanisms. As New Horizons advances to the edge of the solar system, SDC measurements continue to refine our understanding of the outer solar system’s dust environment, extent, and its implications for dust disks around other stars.
How to cite: Doner, A., Corbett, T., Schulze, B., Horanyi, M., Brandt, P., Poppe, A., Stern, A., Singer, K., and Verbiscer, A.: New Horizons’ Student Dust Counter: Potential Compositional Insights at 61 AU Heliocentric Distance, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-13978, https://doi.org/10.5194/egusphere-egu25-13978, 2025.
The DESTINY+ mission, led by the Japan Aerospace Exploration Agency (JAXA), offers a distinctive opportunity for in-situ measurements of cosmic dust. Scheduled for launch in 2028, the spacecraft will use electric propulsion during its interplanetary trajectory toward its target, the active asteroid (3200) Phaethon. A high-speed flyby of Phaethon, with a relative velocity of 35 km/s, is a key mission objective.
The mission's primary scientific payload, the Destiny Dust Analyser (DDA), is being developed by the University of Stuttgart, Germany, in partnership with von Hoerner Sulger GmbH. The DDA’s goal is to characterize the cosmic dust environment encountered along the trajectory through in-situ analysis of individual dust particles. These dust populations range from space debris and interplanetary/interstellar dust to ejecta particles from the lunar surface and Phaethon itself. During the flyby, should Phaethon exhibit activity, dust particles originating from its interior may also be analyzed.
Equipped with a trajectory sensor, the DDA measures the primary surface charge, trajectory, and velocity of individual dust grains. It further conducts compositional analysis via time-of-flight (TOF) mass spectrometry of the impact plasma generated when dust grains collide with the instrument’s target. The charge generated in the impact plasma is also measured, offering additional insights into particle properties.
This paper outlines the DDA’s instrument configuration, provides an update on its development status, and demonstrates its performance using recent TOF mass spectra. Testing has included both positive and negative polarity modes, enabling comparisons of anion and cation mass spectra. Such comparisons are particularly valuable for analyzing organic-rich dust particles.
How to cite: Srama, R., Acker, D., Arai, T., Bauer, M., Beck, A., Fröhlich, P., Greaesslin, M., Henselowsky, C., Hirai, T., Ingerl, S., Kobayashi, M., Komposch, M., Krueger, H., Lengowski, M., Li, Y., Mocker, A., Khawaja, N., Simolka, J., Sterken, V., and Strack, H.: The DESTINY+ Dust Analyser (DDA) for in-situ Cosmic Dust Measurements, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-19660, https://doi.org/10.5194/egusphere-egu25-19660, 2025.
Due to the relative motion of the solar system through its local interstellar environment, interstellar dust can enter the heliosphere. The dust trajectories are influenced by gravitational forces, solar radiation pressure force and by the solar wind through the Lorentz force on charged dust grains. Finally, these interstellar micro-particles can be measured in the solar system by in situ cosmic dust instruments.
One of the most extensive in situ interstellar dust databases stems from the Ulysses dust detector. However, distinguishing interplanetary from interstellar dust is a major challenge and the selection criteria may influence the conclusions made based on the interstellar dust dataset.
In this work, we elaborate on how the selection criteria and mass determination methods influence the inferred ISD population bulk properties like the dust particle flux, flow direction, and the gas-to-dust mass ratio in the interstellar medium. We examine the largest dust grains that were selected as "interstellar" and we illustrate a methodology to infer the filtering at the heliosphere's outer regions (heliosheath) using in situ data in the solar system, simulations of dust transport in the heliosphere inside of the termination shock, and assumptions on the initial dust size distribution from astronomical observations.
We conclude with lessons learned for future detectors, in particular the necessity to use velocity grids and large detector surface areas.
How to cite: Sterken, V., Baalmann, L., Janisch, T., Hunziker, S., Strub, P., Krueger, H., Hofstetter, K., and Sieber, M.: Lessons learned from Ulysses data analysis for future interstellar dust detectors in space, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-17182, https://doi.org/10.5194/egusphere-egu25-17182, 2025.
The European Space Agency (ESA)’s Lunar Meteoroid Impact Observer (LUMIO), led by Politecnico di Milano and supported by the Italian Space Agency (ASI), the Norwegian Space Agency (NOSA), United Kingdom Space Agency (UKSA), and Swedish National Space Agency (SNSA), is a 12U CubeSat designed to monitor Lunar Impact Flashes (LIFs) from a quasi-halo orbit around the Earth-Moon L2 point. Scheduled for launch in 2027, LUMIO employs the LUMIO-Cam, a highly sensitive optical instrument acquiring image data in two channels, one in the visible, the other one in the near-infrared spectral range, to observe meteoroid impacts on the Moon’s far side—an area inaccessible to Earth-based observations. LUMIO’s mission will improve our understanding of meteoroid populations, focusing on impactors in the millimeter to decimeter size range. By providing temporal and spatial data on lunar impacts, LUMIO will refine meteoroid flux models critical for planetary defense and space exploration safety. The mission’s synergy with NASA’s Lunar Reconnaissance Orbiter (LRO) will enable precise crater identification and validation of impact models. Additionally, LUMIO may observe asteroid Apophis during its 2029 flyby, providing a unique opportunity to study the interactions of potentially hazardous objects with the Earth-Moon system. This will present recent advancements in modeling the meteoroid environment and progress in LUMIO’s payload development, showcasing the mission’s potential to advance planetary defense through innovative CubeSat technology.
How to cite: Peña-Asensio, E., Ferrari, F., Topputo, F., Gomiero, G., Pizzetti, A., Sughi, S., Koschny, D., Ammannito, E., Zinzi, A., and Moissl, R.: Advancing Planetary Defense with ESA’s Lunar Meteoroid Impact Observer (LUMIO) Mission, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-19567, https://doi.org/10.5194/egusphere-egu25-19567, 2025.
In recent years, space missions have made significant progress in characterizing Near-Earth Asteroids (NEAs), from JAXA's Hayabusa2 mission on Ryugu to NASA's Double Asteroid Redirection Test (DART) mission, which demonstrated a successful kinetic impact on Dimorphos, the secondary of 65803 Didymos binary asteroid system [1]. In the seconds before the impact, the DART spacecraft imagery captured a boulder-strewn surface of Dimorphos. Numerical impact simulations, meanwhile, studied the aftermath of the DART impact to understand the potential cratering and ejecta outcomes through shock physics modeling [2], nevertheless the subsurface remains largely unknown. To explore the internal features of Dimorphos, we simulated a series of DART-scale hypervelocity impacts using the two-dimensional axisymmetric (2DC) version of the iSALE shock physics code [3-5]. Impacts were modeled over longer timeframes on half-spheroidal targets to resolve the surface curvature effect on Dimorphos, incorporating recent mechanical and material constraints from the DART impact [6,7]. Various internal scenarios were tested, ranging from simplified homogeneous to layered heterogeneous interiors with multiple boulders near the impact site. The time evolution of the crater size, ejecta, and momentum transfer efficiency, β, were tracked across simulated scenarios. The results suggest plausible interior scenarios for Dimorphos, whether homogeneous or heterogeneous, that align with the observed β range for the DART impact [8]. Simulations of homogeneous interiors with low cohesions (10-50 Pa) fell within the reference β range when the coefficient of internal friction was set at 0.5, assuming Dimorphos has the same bulk density as the binary system. In addition, decreasing porosity or increasing the friction coefficient led to cohesion values that matched the reference β, approaching 1 Pa. In heterogeneous scenarios, a double-layered interior containing a loose outer layer atop a weak core and a three-layered interior with multiple boulders concentrated at the impact site produced β aligning with the reference β, indicating the potential for diverse interiors in Dimorphos. These findings offer new predictions for the cratering and interior structure of Dimorphos, which the ESA Hera mission will probe [9] during a rendez-vous from a unique proximity in late 2026.
References
[1] Daly et al. (2023). Nature, 616(7957), 443-447. [2] Stickle et al. (2022). The Planetary Science Journal, 3(11), 248. [3] Amsden et al. (1980). LANL Report, LA-8095:101p., New Mexico. [4] Collins et al. (2004). Meteoritics & Planetary Science, 39(2), 217-231. [5] Wünnemann et al. (2006). Icarus, 180(2), 514-527. [6] Luther et al. (2022). The Planetary Science Journal, 3(10), 227. [7] Raducan et al. (2024). Nature Astronomy, 8(4), 445-455. [8] Cheng et al. (2024). Nature, 616(7957), 457-460. [9] Michel et al. (2022). The Planetary Science Journal, 3(7), 160.
How to cite: Senel, C. B., Luther, R., Karatekin, Ö., Collins, G. S., Goderis, S., and Claeys, P.: Predictions for the interior of asteroid Dimorphos through the DART-scale impact modeling, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-18272, https://doi.org/10.5194/egusphere-egu25-18272, 2025.
In the classical theory of planetesimal differentiation, a body would form an iron-rich core, an olivine-dominated mantle, and a pyroxene-rich basaltic crust [1]. The detection of differentiated bodies in the current asteroid main belt will allow us to get insights and study the very initial phases of planetesimal accretion. So far, the only striking proof of a differentiated planetesimal is asteroid (4) Vesta and its family that resulted from the impact formation of two large basins Rheasilvia and Veneneia [2].
Asteroid (22) Kalliope is the densest known asteroid with ⍴=4.4±0.46 g.cm-3 [3] indicating a metal-rich composition. The low radar albedo (0.18±0.05 [4]), however, points towards a lower metal content on the surface but the presence of very high density indicates a differentiated metal-rich interior.
(22) Kalliope has recently been shown to be the parent body of an asteroid family in the outer main belt consisting of 302 members [5]. Therefore, studying the physical properties of the Kalliope family members we can get insights into the internal structure of the original planetesimal.
In this work we studied the physical properties of the Kalliope family.
Thirty seven Kalliope family members have visible reflectance spectra from Gaia DR3 and 22 of which were observed at NASA IRTF obtaining their near-infrared spectra. Following the methodology of our previous work on the Athor asteroid family [6], Gaia and IRTF spectra were combined with the available visible SDSS data. The final combined spectra were classified in the Bus-DeMeo taxonomy [7]. Using the reflectance spectra of Kalliope family members as well as their geometric visible albedos we matched them with meteorites that are included in the RELAB and PSF meteorite lab spectra databases.
We discovered that the Kalliope family is the first family that consists of metallic fragments, confirming the differentiated nature of the original planetesimal.
References: [1] Elkins-Tanton, L. and Weiss, B. (2017), Planetesimals, Cambridge University Press. [2] Marchi S. et al. (2021) Science 336, Issue 6082, 690. [3] Ferraris M. et al. (2022) A&A, 622, A71. [4] Shepard M. K., et al. (2015) Icarus, 245, 38. [5] Brož M. et al. (2022) A&A, 664, A69. [6] Avdellidou C. et al. (2022) A&A, 665, L9. [7] DeMeo F. E. et al. (2009) Icarus, 202, 160.
How to cite: Avdellidou, C., Bhat, U., and Delbo, M.: Kalliope: Discovery of the first metallic asteroid family, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-8804, https://doi.org/10.5194/egusphere-egu25-8804, 2025.
Radar observations of meteor head echoes provide information about the sizes, orbital elements, and atmospheric interactions of microgram-sized dust particles entering the Earth's atmosphere. This work presents preliminary results from an ongoing effort to create a catalog of $10^6$ high-quality meteor head echoes selected from approximately $10^7$ automated meteor head echo detections. The meteors have been observed using the Middle Atmosphere Alomar Radar System (MAARSY) in Andenes, Northern Norway. The catalog includes nearly continuous observations from 2016 to 2024. The catalog contains data on atmospheric trajectories, Doppler shifts, and radar cross-section estimates for each meteor. Atmospheric interactions are modeled using a simplified approach that attributes deceleration solely to atmospheric drag, with each meteor characterized by a single mass-to-area ratio. Atmospheric density is determined using the NRLMSIS 2.0 atmospheric model. For each meteor, Keplerian orbital elements are calculated using the REBOUND numerical propagator, which is employed to remove the influence of the Earth-Moon system prior to atmospheric entry. The catalog can be used to study micrometeoroids on Earth-crossing orbits as well as to analyze the atmospheric entry dynamics of meteoroids.
How to cite: Vierinen, J., Chau, J., Kastinen, D., Zecha, M., Renkwitz, T., Huyghebaert, D., Kero, J., and Latteck, R.: Preliminary results from the 2016-2024 MAARSY meteor head echo survey, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-18621, https://doi.org/10.5194/egusphere-egu25-18621, 2025.
The trans-Neptunian region is observed to host a large proportion and a wide variety of binary systems (components with > a few tens of km in size) [1, 2], offering unique opportunities for studying planetesimal formation from the protoplanetary disk and subsequent evolution [3]. Since trans-Neptunian objects (TNOs) reside far from the Earth, observing TNOs smaller than km-scale remains challenging [4] and consequently, the binarity in this size range is unknown [5].
Doublet craters are generally defined as a pair of adjacent, similarly-sized craters, and are hypothesized to form through simultaneous impacts of widely-separated binaries. The derivable impactor population for Pluto and Charon consists of TNOs smaller than km-scale based upon standard crater scaling laws [6, 7]. Hence, cratering records on these bodies likely contain valuable information about < km-sized widely-separated binaries.
We will present results from our study of doublet craters on Vulcan Planum, Charon, which is the most suitable region owing to its relative low density of craters [6, 7]. We define a potential doublet as a pair of craters with a separation smaller than 1.4x the diameter of the larger crater, and with a ratio of the two diameters greater than 0.4. Through visual inspection, potential doublets are categorized as "unlikely" based on geomorphology such as superposition and/or different degree of degradation, and the rest as "possible". We obtained 39 possible doublets which yields 8% (39 out of 483 craters). Assuming that all possible doublets are true doublets and adopting 15% as the likely fraction of binary impacts resulting in doublets [8], approximately 54% of < km-scale TNOs may be widely-separated binaries. Moreover, we will discuss implications of spatial analyses and the inferred binary population among km-scale TNOs.
Reference [1] Brunini, A. (2020) in "The Trans-Neptunian Solar System" Eds., D., Prialnik, M.A. Burucci, and L.A. Young [2] Noll, K.S., et al. (2020) in "The Trans-Neptunian Solar System" Eds., D., Prialnik, M.A. Burucci, and L.A. Young [3] Fraser, W., et al. (2017) Nature Astronomy, 1, 0088. [4] Arimatsu, K., et al. (2019) Nature Astronomy, 3, 301-306. [5] Thirouin, A., and S.S. Sheppard (2019) The Astronomical Journal, 157, 228. [6] Singer, K.N., et al. (2019) Science, 363, 955-959. [7] Robbins, S.J., et al. (2017) Icarus, 287, 187-206. [8] Miljkovic, K., et al. (2013) Earth and Planetary Science Letters, 363, 121-132.
How to cite: Ikeya, R. and Kirchoff, M.: Doublet craters on Charon and implications for km-sized binaries in the outer solar system, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-667, https://doi.org/10.5194/egusphere-egu25-667, 2025.
The transfer of material between the surfaces of Mars and Phobos is thought to be a key parameter in understanding the formation/evolution of the Martian moons. Past numerical investigations have predicted that, on average, 255 ppm of Martian material should be detectible within the Phobosian regolith. Due to impact gardening processes, this material is assumed to be evenly distributed throughout the regolith material. It is hoped that upon arrival at Phobos, the MMX spacecraft will be capable of identifying the distributed Martian material on Phobos. The main assumption behind the numerical studies is that the Martian material is distinguishable from the Phobosian regolith. The work presented here provides an initial experimental investigation of this assumption, investigating the transport of material from Mars to its moons.
We will use the Kent single-stage light-gas gun to simulate the effect of ejecta production on the Martian surface. We plan a programme of five shots over the speed range of 300-1000 m/s, covering the lower end of the speed regime thought to be relevant for impacts onto Phobos. Projectiles will be fired from a 0.22” (5.56 mm) smoothbore barrel and consisted of a 5.56 mm diameter by 6 mm long 3D-printed UV cured resin shell. The shell is filled with a granular mixture of MGS-1 (Martian simulant) and europium acetate hydrate (Eu(CH3CO2)3·XH2O) as an elemental tracer. The resin shell allows the granular material to be contained, ensuring it impacts the target as a single projectile rather than a dispersed powder. This bespoke projectile construction method provides a complex geological impactor with an elemental tracer to aid in post-shot analysis. Targets will consist of ‘cemented’ PCA-1 Phobos simulant bricks, formed from a mixture of PCA-1 simulant, de-ionised water, and methanol (in the ratio of 60:10:30 wt.%). The mixture is baked in a silicone mould for a period of 24 hours at 80°. During this time the water combined with the clay materials in the simulant causing them to set. During baking, the methanol component evaporates away leaving evenly distributed pore spaces.
Following each shot, analyses is performed on both the impact crater and the collected ejecta. The ejecta material is analysed via x-ray fluorescence and diffraction, focusing on the detection and distribution of potential projectile material. The chemical compositions of the MGS-1 and PCA-1 simulants are highly similar (with NaO being the only component unique to the MGS-1 simulant). The inclusion of the Eu elemental tracer is critical in providing a simple method to confirm the presence projectile material. Analysis of the crater will investigate the distribution of the emplaced projectile material within the target. SEM-EDS analysis of slices through the craters provides a method to investigate both the relative position and depth of any emplaced projectile material. I will report on the bespoke projectile construction and the method of target production. Initial result from the performed shots will also be presented.
How to cite: Finch, J. E., Wozniakiewicz, P., Tandy, J., Burchell, M., Sefton-Nash, E., Avdellidou, C., Alesbrook, L., Koschny, D., and Spathis, V.: Preliminary results of experimental investigations of the transfer of Martian material to Phobos, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-20367, https://doi.org/10.5194/egusphere-egu25-20367, 2025.
The craters on the Martian moons, Phobos and Deimos, are in a state close to geometric saturation, indicating that they are geologically old [1]. Secondary impacts from Phobos are thought to contribute to an increased impact flux beyond expectations [2,3]. Previous crater counting also showed that the trailing hemisphere of Phobos has a higher crater density than the leading hemisphere, obscuring evidence of synchronous orbit with Mars [4]. Additionally, craters of a significant size, identified as secondary in the crater catalog [5], exhibit a distribution showing an asymmetry between the leading and the trailing hemispheres on Phobos, although this asymmetry is less pronounced than predicted by theoretical models.
To investigate this discrepancy, we performed detailed impact simulations by randomly distributing impactors around a virtual sphere modeled 200,000 km from Phobos. The simulations accounted for the gravitational fields and sizes of Mars and Phobos, with varying distances between Mars and Phobos. Our findings indicate that increasing the Mars-Phobos distance decreases the asymmetry between the leading and trailing hemispheres; however, the predicted asymmetry remains larger than observed values. This suggests that additional mechanisms contributing to a higher impact flux may be at play on Phobos, beyond impacts originating from outside the Martian system.
References:
[1]Hirata, N., 2017: Spatial distribution of impact craters on Deimos, Icarus, 288, 69–77.
[2]Ramsley, K. R., and Head III, J. W., 2013: Mars impact ejecta in the regolith of Phobos: bulk concentration and distribution, Planetary and Space Science, 87, 115–129.
[3]Nayak, M., et al., 2016: Effects of mass transfer between Martian satellites on surface geology, Icarus, 267, 220–231.
[4]Schmedemann, N., et al., 2014: The age of Phobos and its largest crater, Stickney, Planetary and Space Science, 102, 152–163.
[5]Salamunićcar, G., et al., 2014: Integrated method for crater detection from topography and optical images and the new PH9224GT catalogue of Phobos impact craters, Advances in Space Research, 53.12, 1798–1809.
How to cite: Kikuchi, H.: Numerical Simulation of Primary Impact Distribution on Phobos, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-8228, https://doi.org/10.5194/egusphere-egu25-8228, 2025.
Building on previous work demonstrating the cascade of planetary impact energy to nanoscale domains, we investigate the mechanisms of nanofracture network formation in asteroidal regolith during the early solar system [1]. Our study focuses on a period characterized by a densified Zodiacal cloud and frequent coronal mass ejections, which could have mobilized nanodust to hypervelocities (~2000 km/s) [2]. Through detailed mathematical modeling, we show that hypervelocity dust grain impacts (v ≈ 2 × 106 m/s) can generate extreme energy densities of approximately 1015J/m3 in nanoscale volumes. Even with minimal energy-to-stress conversion efficiency (~10-6), these impacts produce gigapascal-level stresses sufficient to initiate fracture propagation. Our damage evolution model, incorporating a fourth-rank material property tensor and temperature-dependent activation factors, reveals how these stresses interact with pre-existing flaws in the regolith structure to facilitate fracture formation at lower thresholds than in pristine materials. The damage parameter D evolves according to our derived rate law, which accounts for local stress states and thermal conditions. As D increases, the threshold stress for fracture initiation decreases, creating a progressive weakening effect. Using linear elastic fracture mechanics, we show that initial flaws of approximately 50 nm can propagate under gigapascal stresses when the stress intensity factor KI exceeds the material's fracture toughness KIC (~1 MPa√m). MPa√m is used because, in linear elastic fracture mechanics, the stress at a crack tip scales with the square root of the crack length, naturally combining units of stress (MPa) and √m.
Our calculations reveal that after 104 shock events, the damage increment creates a nanofracture volume fraction of approximately 0.018%. Extrapolating this relationship, we estimate that 5.46 × 106 impacts would generate a significant 10% nanofracture volume fraction, achievable with a total impacting mass equivalent to a few thousand bacterial cells. These interconnected nanofracture networks, influenced by crystallographic structure and pre-existing defects, create extensive reactive surface areas [1] where quantum tunneling effects at nanofracture intersection nodes can facilitate organic synthesis reactions under reduced energy thresholds [3]. Our model indicates that repeated impacts could have created a self-reinforcing damage mechanism, where each generation of nanofractures serves as nucleation sites for subsequent fracture formation.
We conclude that impact-induced nanofracture networks, with their quantum-confined reaction volumes, may have contributed to prebiotic chemical evolution on asteroidal surfaces. In addition, nanofracturing-promoted material disaggregation could have accelerated fine-regolith production early in asteroidal histories, contributing to their bulk fine-grain compositions and the potential nanodust densification of the Zodiacal cloud through frequent impact-related ejections.
References
[1] Rodriguez, J. A. P. et al.: Impact-Generated Nanofracture Networks: A Quantum-Mediated Path to Complex Organic Molecules, LPSC, Abstract #1701, 2025.
[2] Rodriguez, J. A. P. et al.: A Possible New Solution to the Faint Young Sun Paradox: The Role of Super Solar Flare Coronal Mass Ejections on Dust Dynamics in Early Planetary Warming, LPSC, Abstract #1633, 2024.
[3] Rodriguez, J. A. P. et al.: Nanofractures: Sites of Emergent Habitability and Quantum-Mediated Organic Synthesis, LPSC, Abstract #2104, 2025.
How to cite: Rodriguez, J. A. P., Teodoro, L., Bremner, P. M., and Krause, L. H.: Hypervelocity Impact-Induced Nanofracture Networks in Asteroidal Regolith: A Pathway for Quantum-Mediated Organic Synthesis, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-13408, https://doi.org/10.5194/egusphere-egu25-13408, 2025.
Iron-rich bodies have been proposed to be the result of high-energy collisions removing most of the silicate mantle from differentiated bodies [1]. Here we use the results of high velocity sub-catastrophic collisions at 10 km/s into differentiated planetesimals with initially 30-40 km thick mantles and 100 km radius iron cores performed using the iSALE-2D shock physics code [2]. In order to study the long-term thermal evolution of these iron-rich remnant bodies, we employ a 1D finite-difference code considering material-dependent heat diffusion, latent heat of crystallization and time-dependent radiogenic heating by 26Al and 60Fe in the leftover mantle and the iron core, respectively. For the thermal evolution calculations, we use an initial composition and temperature structure based on radial profiles through the center of the post-impact bodies. The start time after CAI formation of the long-term models is based on the Pd-Ag dating for various iron meteorites [3]. Finally, we compare the results with the cooling rate constraints for various iron meteorite types based on Widmanstätten pattern formation [4] and Pd-Ag data [3] with both methods covering different temperature intervals during the body’s cooling.
References:
[1] Asphaug, E., C. B. Agnor & Q. Williams (2006). Nature 439, 155–160.
[2] Raducan, S. D., M. Jutzi, T. M. Davison & G. S. Collins (2022). 85th Annual Meeting of The Meteoritical Society, 2695.
[3] Hunt, A. C., K. J. Theis, M. Rehkämper, G. K. Benedix, R. Andreasen & M. Schönbächler (2022). Nat. Astron. 6, 812-818.
[4] Goldstein, J. I., E. R. D. Scott & N. L. Chabot (2009). Chem. Erde 69, 293–325.
How to cite: Raducan, S. D., Golabek, G., Zippoli, M., and Jutzi, M.: Post-impact thermal evolution of iron-rich planetesimals, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-17777, https://doi.org/10.5194/egusphere-egu25-17777, 2025.
We present an investigation of the dust distribution in the Saturn’s rings based on hypervelocity dust impacts observed by the Cosmic Dust Analyzer (CDA) and the Radio and Plasma Wave Science (RPWS) instrument on board the Cassini spacecraft. The dust impacts create spiky signals in the electric field waveforms that are used to determine profiles of impact count rate, dust mass, and evaluated wave power spectral density (PSD) during the ring crossings. Information about the dust composition and velocity is extracted from the available CDA data. The calculated profiles of the ring crossings are then employed to determine the width of the rings and their displacement from the equatorial plane as a function of radial distance from Saturn center in the range from 2.46 to 5.85 Rs. This dependence shows a significant enhancement of the dust density within the Janus/Epimetheus ring region at 2.46 — 2.56 Rs and at the Enceladus orbit at 3.95 Rs. The resolved dust impact rate and PSD profiles show a good agreement in the width and displacement of the investigated rings. Relations are found between the PSDs and the number of dust impact signals, and their amplitudes present in the waveform. Our results show that the calculated PSDs have strong dependence on the relative velocity between dust and spacecraft. The observed one order PSD variation at a fixed radial distance for a constant relative dust-spacecraft velocity is probably related to the variability of the dust population in the examined Janus/Epimetheus ring.
How to cite: Nouzak, L., Ijaz, S., Pisa, D., Pavlu, J., Vaverka, J., Nemec, F., Safrankova, J., and Nemecek, Z.: Dust detection in the Saturn rings by the Cassini spacecraft, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-5171, https://doi.org/10.5194/egusphere-egu25-5171, 2025.
This study investigates the distribution of dust in Saturn’s rings, analyzing dust impact signals detected by the Radio and Plasma Wave Science (RPWS) instrument aboard the Cassini spacecraft. Over its 13-year mission, the electric field antennas of RPWS registered sharp spiky signals caused by hypervelocity dust impacts. Data from multiple ring crossings were analyzed using the power spectral method. The vertical profiles and spectral amplitudes were determined in radial distances of 2.45 to 4.5 Rs from the center of Saturn. The results show the spatial distribution of dust density profiles, spectral amplitudes, and power density variations with radial distance. The power density exhibited strong variability for a constant relative dust-to-spacecraft velocity, indicating environmental differences at fixed radial distances. The profiles derived from the spectral analysis of electric field measurements closely align with those obtained through a search algorithm that uses recorded waveforms. The study indicates that the profiles can be modeled by a Gaussian distribution, with half-width thicknesses ranging from 450 km in the dense, narrow G ring to 3000-4000 km in the wide E ring. Our findings contribute to a deeper understanding of the Saturn dust environment and demonstrate an alternative approach for analyzing hypervelocity dust impacts in planetary environments.
How to cite: Ijaz, S., Nouzak, L., Vaverka, J., Pavlu, J., Nemec, F., Pisa, D., Nemecek, Z., and Safrankova, J.: Analyzing Dust Distribution in Saturn Environment using Power Spectra from Cassini RPWS, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-5165, https://doi.org/10.5194/egusphere-egu25-5165, 2025.
Dust in the interplanetary space and around planets can be observed by specialized detectors that allow determination of many parameters like velocity, mass or even mass composition of the registered dust grains but the principal disadvantage of such detectors is their small geometrical factor. On the other hand, the dust grains are impacting the whole spacecraft body and these impacts can influence the spacecraft potential by various mechanisms and thus can be used for detection of dust impacts by electric antennas. The electric field instruments register dust impacts as short pulses resulting from the interplay between plasma cloud generated by the dust impact and surrounding plasma environment. This method has been used by many investigators in the interplanetary space as well as in vicinity of several planes like Earth, Mars, Jupiter or Saturn. We critically survey these investigations with an emphasis on the influence of the surrounding environment on a (mis)interpretation of the electric field measurements.
How to cite: Pavlu, J., Ijaz, S., Nouzak, L., Safrankova, J., Nemecek, Z., and Vaverka, J.: What is the role of surrounding environment in registration of dust around planets?, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-18884, https://doi.org/10.5194/egusphere-egu25-18884, 2025.
