bluuebunny/crossref_metadata_2025 huggingface dataset:
Insights on dense silicate melts from shock-compression coupled to in situ X-ray probes
Authors: Hernandez Jean-Alexis , Morard Guillaume , Lacquement Antoine , Nagy Charlotte , Pege Clara , Libon Lélia , Ravasio Alessandra , Wei Xui , Pandolfi Silvia , Prescher Clemens , Alonso-Mori Roberto , Gleason Arianna , Mao Wendy , Shim Sang-Heon , Balugani Sofia , Torchio Raffaella , Sévelin-Radiguet Nicolas , Chantel Julien , Merkel Sébastien , Boccato Silvia ,   9 other contributors
Published: July 2024

Molten silicates existing at depth play an important role in planetary evolution. Yet, understanding the local structure and properties of liquid silicates under extreme pressure and temperature remains challenging due to the inherent complexities of experimental measurements in such conditions and to the theoretical challenges caused to atomistic simulations by the description of Fe atom behavior. In this presentation, we will show recent results obtained by coupling laser-driven dynamic compression to in situ X-ray probes at the MEC end-station of LCLS at SLAC (Menlo Park, CA, USA) and at the ID24-HPLF instrument at the ESRF (Grenoble, France). The combination of the ultrabright X-ray sources and high-power optical lasers allowed us to probe the local atomic arrangement, spin-state and insights on the electronic structure of shock compressed liquid (Mg,Fe)SiO3 and other Fe-bearing compositions up to 400 GPa along their Hugoniot.
A spectral method to account for variable electrical conductivity in the dilute cores of the Gas Giants
Authors: Dobrynina Sofya , Maffei Stefano , Jackson Andrew
Published: July 2024

Ever since the first satellite flybys of the Gas Giants, executed by the Pioneer and Voyager missions of the 1970s, the scope of the study of the interior structure and dynamics of Jupiter and Saturn has grown exponentially. Currently, with the wealth of data obtained from the Cassini-Huygens and Juno missions, we are able to construct more comprehensive models of these planets’ interior structures that would be able to explain and recreate some of their characteristic features, namely the general properties of their observed magnetic fields and zonal flows, and enable us to develop theories not only on planetary magnetism, but also on planetary formation, evolution, and our Solar System as a whole.Recent studies of the Jovian and Saturnian gravity fields suggest that both planets are likely to have dilute cores, characterised by an inhomogeneous heavy-element compositional gradient. This opens an opportunity to explore an alternative, full-sphere dynamo model, and compare it to previous standard models, which assume the presence of a distinct heavy-element inner core. Thus, the need arises for modified numerical interpretations, concerning boundary conditions and considerations of material properties, for the dynamo process in the presence of these dilute cores. To add to this, effects of a fully convective dilute core, double-diffusive convection, a more complex interior structure involving stably stratified layers, as well variable electrical conductivity are desired in order to consolidate the new model. To date, the majority of studies on electrical conductivity have assumed a near constant conductivity profile in the dynamo region, before having a steeply decaying conductivity in the outer envelope regions, in accordance with ab initio calculations. However, as part of the dilute core model, it is now all the more interesting to consider possible variations in the electrical conductivity profile, provided by the heavy-element gradient, in the dynamo region. This investigation may shine some light on any further potential complexities existing within the internal structures of Jupiter and Saturn, whether these add anything to our current models, and how these considerations ultimately affect the observed magnetic fields produced in simulations.To this end, an eigensolver based on the Tau Spectral Method, and using Jones-Worland polynomials as basis functions, is proposed to obtain the magnetic decay eigenmodes from the magnetic induction equation in the toroidal and poloidal decomposition, when there are no contributions from kinematic dynamo action (ie, the flow u=0). This eigensolver aims to show whether this method is indeed effective to apply to the case of a fully-spherical geometry with variable electrical conductivity, with the goal of comparing this methodology with the collocation method used in existing dynamo simulation codes, such as MagIC, and conclude its worth in the pursuit of further studies.
Mercury interior characteristics inferred from geodetic measurements 
Authors: Briaud Arthur , Oberst Jürgen , Stark Alexander , Hussmann Hauke , Xiao Haifeng
Published: July 2024

Mercury exhibits unique dynamics because of its proximity to the Sun and its elliptical orbit. The eccentricity combined with the Sun's gravitational pull, results in periodic variations in tidal forces and associated surface deformations. In particular, the tidal forces generate periodic variations in the shape and gravity of Mercury, depending on its internal composition and structure. These variations, described as "Tidal Love numbers" (TLNs), are valuable indicators of Mercury’s deep structure. Precise measurements such as by laser and radar altimetry are required to estimate these deformations as well as radio science for precise determination of changes in the gravity field. Recent research by Bertone et al. (2021) used data from the Mercury Laser Altimeter of the MESSENGER spacecraft to estimate the h2 tidal Love number. Previous studies, such as those by Steinbrügge et al. (2018) and Goossens et al. (2022), offer additional insights into relationships between Mercury deformation and interior. However, there are still significant uncertainties in geodetic measurements that prevent unique models of Mercury's deep interior.To better understand the internal structure of Mercury, we plan to use new reduction techniques for MESSENGER altimetry (Xiao et al., this meeting) and recently obtained physical constraints on the interior of the planet. Our approach will involve exploring various combinations of radii, densities, shear modulus, and viscosities while considering the rheology of each layer from the planet's core to its surface. We will then compare our modelled results with available estimates of tidal deformation, mass, and moment of inertia, to decipher the interior composition of Mercury.References:Steinbrügge, G., Padovan, S., Hussmann, H., Steinke, T., Stark, A., & Oberst, J. (2018). Viscoelastic tides of Mercury and the determination of its inner core size. Journal of Geophysical Research: Planets, 123(10), 2760-2772.Bertone, S., Mazarico, E., Barker, M. K., Goossens, S., Sabaka, T. J., Neumann, G. A., & Smith, D. E. (2021). Deriving Mercury geodetic parameters with altimetric crossovers from the Mercury Laser Altimeter (MLA). Journal of Geophysical Research: Planets, 126(4), e2020JE006683.Goossens, S., Renaud, J. P., Henning, W. G., Mazarico, E., Bertone, S., & Genova, A. (2022). Evaluation of recent measurements of Mercury’s moments of inertia and tides using a comprehensive Markov chain Monte Carlo method. The Planetary Science Journal, 3(2), 37.Xiao, H., Stark, A., Steinbrügge, G., Briaud, A., Lara, L M., Gutiérrez, P J., [IN PREP]. Mercury’s tidal Love number h2 from co-registration of reprocessed MLA profiles
The volatile content of giant Oort cloud comet C/2014 UN271 during its return to the planetary region.
Authors: Bolin Bryce
Published: July 2024

Comets are relatively-pristine remnants of the original planetesimals that were ejected from the planetary region in the late stages of planetary formation. The Oort cloud comet C/2014 UN271, hereafter UN271, is ~140 km in diameter, large enough that it could be an intact example of a planetesimal that formed in the protoplanetary disk before being ejected into the Oort cloud. UN271 is currently beyond 17 au from the Sun as it moves to a perihelion distance of 11 au in 2031. Given its large heliocentric distance, the temperatures on and below its surface are too low for efficient sublimation of water ice. It is likely that its activity is driven by hypervolatiles such as CO or CO2 and not H2O. It is dynamically new on its first inbound trip to the Solar System's planetary region providing the rare opportunity to study the volatile content of one of the original planetesimals in a pristine state. We present JWST/NIRSpec prism IFU observations of UN271 with R~100 covering the spectral range where we can detect emission features from the vibrational bands of the gas-phase all the main volatiles found in comets (such as CO2, CO and C2H6). Moreover, this range also includes absorption bands of solid-phase water-ice grains. Our observations, taken on December 22, 2022, when the comet was at 18.6 au from the Sun, provide constraints on the comet's CO and CO2 production rates, the activity driving mechanism, the presence and nature of water-ice grains in its coma and can be compared with similar spectra of Kuiper Belt bodies. We will discuss the implications for the timing of the formation of the original planetesimals as well as UN271's formation environment within the primordial Kuiper Belt.
Molecular Transformations and Spectroscopy for Understanding Extra-Terrestrial Atmospheres
Authors: Frandsen Benjamin , Skog Robert
Published: July 2024

A new era dawns in the exploration of planetary atmospheres. The James Webb Space Telescope  (JWST) having started to record high-resolution spectra of exoplanetary atmospheres. Atmospheric Remote-sensing Infrared Exoplanet Large-survey (ARIEL) is soon to follow in 2029. Furthermore, new missions with orbiters and landing crafts are being launched within the next decade to study bodies in the solar system. Of particular interest to us is Venus with one active orbiter and four upcoming missions.From our physical chemistry background we drive exploration of molecular level chemistry in atmospheres using computational chemistry (ab initio) methods and laboratory based spectroscopy. In this manner we can influence the scope of future missions and enable discovery of novel molecules, ultimately expanding our understanding of planetary atmospheres.Here I show results from our work in uncovering novel chemical reactions and identifying spectral signatures, all of which can be directly implemented into atmospheric models. The Venusian atmosphere has rich and diverse chemistry, especially sulfur chemistry, and remains a great source of inspiration for our starting points. However, the impact of our results goes beyond Venus and into both the atmosphere of Jupiter's moon Io, and exoplanets such as LHS 475b, where SO2 has been observed.The presentation includes novel unpublished reactions with an assessment of how impactful these might be on Venus. Furthermore, I present perspectives on candidate molecules for matching the enigmatic UV absorption on Venus, demonstrating how some previously suggested candidates cannot match, and narrowing down the possible candidates.
JUICE mission news 
Authors: Altobelli Nicolas , Witasse Olivier , Vallat Claire , Tanco Ignacio , Dietz Angela , Erd Christian
Published: July 2024

The JUICE mission has been launched by an Ariane 5 launcher on April 14, 2023 and is now on its way to reach Jupiter and its icy moons in 2031. The focus of JUICE is to characterise the conditions that may have led to the emergence of habitable environments among the Jovian icy satellites, with special emphasis on the internally active ocean-bearing worlds, Ganymede and Europa. Following a Jupiter Touring phase of 4 years, JUICE will become the first orbiter of a moon that is not our own, entering Ganymede orbit in 2034.The spacecraft passed its commissioning review successfully on July 19, 2023, following the Near Earth Commissioning Phase (NECP), and, despite a few hickups, the ESA and multi-national instruments teams are now operating our interplanetary ship successfully. We report on the interplanetary cruise so far, and in particular on the first-ever Moon-Earth double gravity assist manouver performed on August 19-20. 
Field trip to at Makgadikgadi Salt Pans- a multimedia outreach project to capture the day-to-day human story of planetary science, to raise awareness of Europlanet and of the diverse research projects taking place at a planetary field analogue.
Authors: Shaw Niamh , Franchi Fulvio , Shawel Mebatseyon , Kahsay Trhas Hadush
Published: July 2024

 There is a societal obligation to communicate planetary science activities to the general public. Many science and technology breakthroughs go unnoticed too frequently due to a lack of interest or awareness from the general public and an inability of scientists to engage broad audiences effectively.  In July 2023, science communicator Niamh Shaw accompanied field geophysicist Mebatseyon Shawel  on a six-day TA2023-funded field trip entitled 'Investigation of geomorphic features in Ntwetwe pans, Makgadikgadi Basin, Botswana, using Ground Penetrating Radar: implications for Martial surface landforms'. The expedition to the Makgadikgadi salt pan was led by Fulvio Franchii and team at BUIST, Botswana. The purpose of a science communicator as documentarian was to capture the story of one science team on a field trip to the Makgadikgadi Salt pans.   The overall objectives of the science communication study were to capture public interest in planetary science taking place in Botswana,  the Makgadikgadi Salt pans and space, through focussing on telling the real-time story of  a science analogue pre-, during- and post-mission, highlighting  the importance of Analogue sites, specifically the Makgadikgadi Salt Pans, and the opportunity for non-Space audiences individuals to better appreciate planetary science.  Using a number of media forms the story of this six day field trip was captured through video, photography, audio and personal testimony. The story of the field trip was presented to schools and family audiences in Brazil, Ireland, Canada and the USA.  The presentation capably captured the public’s interest by telling the human story of a science mission conducting a field trip, as evidenced by many follow-up questions. There was little or no knowledge of planetary science or analogues in the audience prior to the presentation.  Photographs of the mission were included in science publications post-field trip. The use of personal testimony as a method for informal science learning is an effective and original approach to highlight the importance of planetary science analogues to the general public. In simple terms, it was found that seeing a daily account of what scientists do, is immediate and accessible to viewers and readers.  
Seasonal variation of Titan’s stratospheric tilt
Authors: Wright Lucy , Teanby Nicholas A. , Irwin Patrick G. J. , Nixon Conor A. , Ford Joshua S.
Published: July 2024

Titan’s entire stratosphere is in superrotation and rotates about an axis offset by approximately 4o from its solid-body rotation axis [1]. However, the mechanism causing this offset is not yet understood. The tilted axis has been determined previously through temperature retrievals [1, 2], composition retrievals [3, 4], and by analysis of images of stratospheric haze [5, 6, 7] and polar clouds [8]. We independently determine the magnitude and direction of the stratospheric tilt from temperature and composition maps at a higher spatial resolution compared to previous studies. This is achieved by inverting mid-infrared spectra (580—1500 cm-1) acquired by Cassini’s Composite Infrared Spectrometer (CIRS) [9-11] and using the NEMESIS [12] radiative transfer and retrieval tool.We use observations acquired at low-spectral resolution (SR, FWHM ~ 14.5 cm-1) with nadir viewing geometry. These observations offer excellent spatial and temporal coverage throughout the Cassini mission (Figure 1) and typically have the best horizontal spatial resolution and lowest noise per spectrum of any of the CIRS observations. While spectral features in these data are often blended and subtle, previous studies have demonstrated accurate modelling using NEMESIS [12] with a correlated-k forward model [13].In addition to determining an average stratospheric tilt, we investigate the seasonal evolution of the tilted axis over almost half a Titan year (2004—2017). This takes advantage of the excellent temporal coverage of the underused CIRS low-SR dataset. The seasonal evolution of the tilt is not well known and has only been determined for the full Cassini mission through Titan’s stratospheric haze annuli [14]. However, these annuli are observed at higher altitudes than the region probed by our retrievals, which are sensitive to approximately 1 mbar. Moreover, the haze annuli can become unclear around 2012—2015 as Titan’s mean meridional overturning circulation reverses. Our study should provide a more reliable estimate for the tilt during this period, and a powerful independent comparison to [14] over the full Cassini mission. Quantifying Titan’s stratospheric tilt axis, and its potential seasonal evolution, yields valuable insight into the dynamics responsible for the offset and the mechanisms that drive superrotating atmospheres in general.Figure 1      Mission coverage of the observations used. We use low-spectral resolution nadir spectra acquired by Cassini’s CIRS instrument. The acquisition date of each observation sequence is indicated by colour.References: [1] Achterberg et al., 2008b [2] Achterberg et al., 2011 [3] Teanby et al., 2010 [4] Sharkey et al., 2020 [5] Roman et al., 2009 [6] Kutsop et al., 2022 [7] Vashist et al., 2023 [8] West et al., 2016 [9] Flasar et al., 2004 [10] Jennings et al., 2017, [11] Nixon et al., 2019 [12] Irwin et al., 2008 [13] Wright et al., 2024 [14] Kutsop et al., 2022.
Clouds and Storms as seen by HRSC - A catalogue of atmospheric phenomena on Mars 
Authors: Tirsch Daniela , Machado Pedro , Brasil Francisco , Hernández-Bernal Jorge , Sánchez-Lavega Agustín , Carter John , Montmessin Franck , Hauber Ernst , Matz Klaus-Dieter , Nair Ashwathy
Published: July 2024

Due to the elliptical orbit of the Mars Express (MEX) spacecraft, its High Resolution Stereo Camera (HRSC [1]; spectral range 0.395-1.015 µm) can not only take surface observations from low altitude (near periapsis) to map the planet at the highest possible resolution (12.5 m/px), but also capture observations from higher altitudes at lower resolution (200 – 800 m/px, depending on observation altitude), covering much larger parts of the surface with a typical field of view from limb to limb. These high-altitude observations are ideal for observing atmospheric phenomena on Mars. After more than 20 years of the MEX mission, an extensive amount of image data on atmospheric phenomena on Mars has been accumulated, which has a great potential for scientific exploitation.We have visually analyzed all HRSC high-altitude observations with respect to atmospheric phenomena such as clouds of different types, dust storms, cyclones, dust lifting events and other features, and compiled a database that should provide easy access to the information on what kind of phenomena can be found in which HRSC image. We have classified the different cloud types, compiled useful additional information and parameters (metadata), and analyzed the occurrence of each feature/event with respect to seasons and geographical locations. In a next step, this information will be used for further scientific applications such as spectral characterization of cloud compositions, cloud/wind speed and direction measurements, cloud height estimates and the analysis of the physical mechanisms behind the phenomena.We will present our first results of this project and introduce the database, show examples of observed feature types and morphologies, present maps of the occurrence of phenomena on Mars and give examples of scientific applications. [1] Jaumann, R., et al., 2007. The high-resolution stereo camera (HRSC) experiment on Mars Express: Instrument aspects and experiment conduct from interplanetary cruise through the nominal mission. Planetary and Space Science 55, 928-952. Fig. 1: Current status of the database entries showing the occurrence of the respective cloud types and storm events by geographic location and season. (ACB = Aphelion Cloud Belt; EDC = Elongated Dust Clouds; background: blended HRSC/MOLA DTM and shaded relief) 
Moon crust and upper mantle revealed by seismic interferometry methods applied to Apollo seismic data
Authors: Torrent Duch Arnau , Garcia Raphael F. , Drilleau Mélanie
Published: July 2024

The Moon has recently been put back into the spotlight for space exploration. As our closest astral neighbor, the Moon is an accessible differentiated planetary body which provides insight into the formation and differentiation of inner solar system bodies. Back in the seventies, NASA’s Apollo program conducted several exploration and sample return missions to better understand our natural satellite. Five of these missions included the deployment of seismometers for passive and active seismology. We process the passive seismology records by using seismic interferometry methods. Cross-correlations and auto-correlations between the different seismometers deployed by the Apollo missions are computed and analyzed to retrieve Moon’s internal structure. The seismic interferometry method is applied to the coda of seismic events detected by the Apollo seismic network. The events are selected based on their quality and the presence or lack of significant gaps in the data. Auto-correlations are computed on time series whitened using 1-bit normalization. Each event is processed independently. The Signal-to-Noise Ratio (SNR) of correlations is calculated by comparing the envelope of the stacked correlations to the amplitude of the residual fluctuations between events and between different time windows in the coda. An additional data selection step is added in order to exclude data that do not show an enhancement of the auto-correlation spectrum at frequencies for which the seismometer is most sensitive.The evolution of the auto-correlation SNR as a function of time in the coda is consistent with the SNR of the seismic data. Auto-correlations of vertical components show seismic phase arrivals in the 13-90s time range which are consistent between two Apollo stations.These arrivals are interpreted in terms of seismic waves reflected on crust and mantle interfaces. A preliminary crust and mantle model of these interfaces is deduced and validated by comparing vertical and horizontal auto-correlation results. The analysis of the cross-correlations between Apollo stations is also presented. Additional validation tests are implemented to ensure that the detected arrivals are not due to data artefacts at a given periodicity. 
The Asteroid Framing Cameras on ESA’s Hera mission
Authors: Vincent Jean-Baptiste , Kovacs Gábor , Nagy Balázs , Preusker Frank , Pajola Maurizio , Kueppers Michael , Michel Patrick
Published: July 2024

As the first asteroid deflection test, NASA’s successfully hit asteroid Dimorphos (secondary of the Didymos system) with the DART kinetic impactor in September 2022. To fully characterize the physical properties of the objects, and measure precisely the effects of this impact in the context of planetary defense, ESA is launching the Hera mission in October 2024, with scheduled arrival at Didymos in 2026.Among the core payload of the mission, the Asteroid Framing Cameras are two identical panchromatic imaging systems that will support navigation and scientific activities, by acquiring images from various distances and observing geometries during the course of the mission.Built by Jena-Optronik (Germany), the cameras will provide data that support a wide range of investigations: hazard detection, system dynamics, mapping, shape reconstruction, morphology, albedo. These observations are critical to understand the current state of the Didymos system. By providing a detailed characterization of the asteroids surfaces, shapes, and the dynamical state of the system, the AFCs will contribute necessary data to fully assess the outcome of the DART impact, concluding this first planetary defense test.Each instrument is equipped with a 5.5 x 5.5-degree field of view, and a pixel resolution of 93.7 microradians, and meet the requirements defined by the mission science team. We expect to deliver global mapping of the asteroids at spatial scales of 2–3 m/pixel in the Early Characterization Phase, 1–2 m/pixel in the Detailed Characterization Phase, and 0.5-2 m/pixel in the Close Operation Phase. Dedicated flybys will bring the resolution down to < 10 cm/pixel on specific areas of interest such as the DART impact site and the JUVENTAS cubesat landing site.At EPSC, we will present the technical specifications of the camera, as well as the status of the calibration. We will then summarize the planned operations in cruise and at the asteroids. Finally, we will provide examples of the scientific investigations and products that will make use of the data returned by the cameras (e.g. shape model, morphological characterization).
Rossiter-McLaughlin effect of a sub-Neptune in a resonant chain system
Authors: Zak Jiri , Bocchieri Andrea ,   collaborators
Published: July 2024

Planetary systems in mean motion resonances hold a special place among the planetary population. They allow us to study planet formation in great detail as dissipative processes are thought to have played an important role in their existence. Additionally, planetary masses in bright resonant systems may be independently measured both by radial velocities (RVs) and transit timing variations (TTVs). In principle, they also allow us to quickly determine the inclination of all planets in the system, as for the system to be stable, they are likely all in coplanar orbits. To describe the full dynamical state of the system, we also need the stellar obliquity that provides the orbital alignment of a planet with respect to the spin of their host star and can be measured thanks to the Rossiter-McLaughlin effect. It was recently discovered that HD 110067 harbours a system of six sub-Neptunes in resonant chain orbits. We will show ESPRESSO high-resolution spectroscopic time series of HD 110067 during the transit of planet c. We find the orbit of HD 110067c to be well aligned. This result is indicative that the current architecture of the system has been reached through convergent migration without any major disruptive events. Finally, we will report transit-timing variation in this system as we find a significant offset of 19 ± 4 minutes in the center of the transit compared to the published ephemeris.
Jupiter’s magnetic field geometry and its relation with new decameter radiation events observed by Juno
Authors: Martos Yasmina M. , Ramirez Eduardo , Connerney Jack E.P. , Kurth William , Imai Masafumi , Kotsiaros Stavros
Published: July 2024

Decametric radio emissions (DAM) originating in Jupiter’s polar aurorae ought to generate along magnetic field lines at the local electron gyrofrequency. The Io-related DAM have received particular attention since the 1980’s, and it is expected that the maximum frequency of these emissions is bounded by the maximum magnetic field strength near the footprint of the instantaneous Io Flux Tube. DAM have been observed from Earth and spacecraft flybys before Juno, limiting the observation geometry to equatorial latitudes. Since 2016, and thanks to Juno, we have been able to observe Io-related DAM from a wide range of latitudes, leading to the observation of a new DAM feature that we preliminarily called “butterfly”. We analyze the Waves data from May 2016 to June 2023 searching for these butterflies to catalog them and determine their relationship with Io and the Jovian magnetic field. Based on the observation geometries, we found that these events (~ 135) are Io-related, they are always observed when Juno is in southern latitudes, they last for ~5 hours and their maximum observed frequency is ~20 MHz. As Juno is spending more time in southern latitudes as the mission progresses, the observation of butterflies keeps increasing over the years. Here, we study the role of the dipolar magnetic field of the southern hemisphere of Jupiter in the generation and observation of the butterfly events.
Multiband Ionospheric Ultra-Violet Spectrum Imager (MUSI) onboard the Fengyun Satellite
Authors: Liu Mohan , Zhang Xiao-Xin , Fu Liping
Published: July 2024

The dynamic thermosphere-ionosphere (T-I) system exhibits a significant response to energy inputs from magnetosphere and lower atmosphere, which leads to rapid changes and regional disturbance in the ionosphere. To monitor the T-I system over China in real time, a Multiband Ionospheric Ultra-Violet Spectrum Imager (MUSI), with a launch scheduled for 2025, will be hosted on the Fengyun-4C satellite, which is in geostationary orbit at 133°E longitude and supported by the China Meteorological Administration. MUSI is an imaging spectrometer. It will provide an opportunity to understand spatial and temporal variability of the T-I system over China due to different kinds of energy inputs by measuring the Earth’s far ultraviolet (120-160 nm) airglow with spectral resolution of 0.4 nm. MUSI’s field of regard is 14° East-West and 16° North-South. The observations includes simultaneous monochromatic images of the sunlit and nightside disk each day produced at four ‘colors’, i.e., HI 121.6 nm, OI 130.4 nm, OI 135.6 nm, and 140-160 nm N2 Lyman-Birge Hopfield bands. Further information, such as the O/N2 column density ratios during the day and the ionospheric peak electron density during the night, will also be derived.
Why are planets and flybys important for debris discs?
Authors: Pearce Tim
Published: July 2024

Debris discs are belts of planetesimals and dust, like the Asteroid Belt and Kuiper Belt in our Solar System. These discs are a fundamental component of planetary systems, and many such discs have been resolved around other stars. Debris discs show a broad diversity of locations, shapes and features, and we do not understand the origin of this diversity. However, these discs must be telling us something about the architecture, formation and evolution of planetary systems.One reason that debris discs are important is that they contain imprints of historical dynamical interactions, which can persist long after the events that caused them. For example, planets can gravitationally interact with debris, and this interaction generates disc features like gaps, warps and clumps. Similarly, stellar flybys can produce long-lasting debris structures in the outer regions of planetary systems. Now, with the arrival of new dynamical theory and observational capabilities, we are extremely well placed to interpret the clues that debris discs are giving us.In this talk, I will summarise what planets or flybys would do to debris discs. In particular, I will focus on the observable signatures that these interactions would leave on discs. I will describe why conventional debris models often rely on such interactions having occurred, and what it would mean for debris science if this assumption proved incompatible with observations. I will also discuss how upcoming theory and observations may finally answer some key questions about debris and planetary systems. A wealth of new debris-disc data will arrive over the next few years, and as a community we must be prepared to interpret it.
Long-term variations of temperature and H2SO4 gas mixing ratio in the Venusian atmosphere studied with Venus Express and Akatsuki radio occultation measurements
Authors: Ando Hiroki , Noguchi Katsuyuki , Imamura Takeshi , Sagawa Hideo , Oschlisniok Janusz , Tellmann Silvia , Pätzold Martin
Published: July 2024

It is well known that planetary atmospheres have a wide range of time-scale variations that have a significant impact on the surface environment of the planet. Taking the Earth as an example, long-term scale atmospheric variations such as ENSO and QBO are affecting the Earth's weather and climate. On the other hand, whether such long-term scale atmospheric variations exist in planetary atmospheres other than Earth has not been much studied in the past. A change in this situation has been brought by the recent realization of long-term observations of the Venusian atmosphere by Venus Express and Akatsuki: the presence of significant long-term variations in UV albedo and the zonal mean wind speed at cloud levels have been reported (Peralta et al., 2018; Lee et al., 2019; Khatuntsev et al., 2023; Horinouchi et al., 2024). In addition, the measurements using ground-based telescopes also have indicated the long-term variations in the mixing ratios of H2O and SO2 gases at the cloud top level (Encrenaz et al., 2023). In this study, we used the vertical profiles of temperature and H2SO4 gas mixing ratio obtained by the Venus Express and Akatsuki radio occultation measurements (e.g., Häusler et al., 2006; Imamura et al., 2017; Ando et al., 2020) and investigated their long-term variations in the low latitude region. As a preliminary result, we found that both temperature and H2SO4 gas mixing ratio around the cloud bottom level (46–50 km altitudes) in 2006–2014 obtained from the radio occultation measurements by Venus Express are generally higher than those in 2016–2022 from the Akatsuki data. In addition, the trend of the annual variation of H2SO4 gas mixing ratio almost follows that of its saturated mixing ratio which is mainly determined by the temperature. In the presentation, we will also discuss the long-term variations of temperature in a wider vertical range from the mesosphere down to the sub-cloud region (~40–85 km altitudes).
Integrating Machine Learning algorithms into Orbit Determination: The AI4POD Framework
Authors: Aigner Benedikt , Dallinger Fabian , Andert Thomas , Pätzold Martin
Published: July 2024

AbstractAccurate orbit determination is essential for mission planning, execution, and maintaining space situational awareness, ensuring the success of space missions and the effective management of space traffic. This is particularly critical for deep space missions, where precise navigation and trajectory estimation are vital for conducting scientific research. While traditional numerical methods for prediction and determination have proven to be robust and accurate, they can be limited when faced with dynamic parameters or unmodeled forces. Integrating machine learning (ML) algorithms offers a way to enhance accuracy, especially for models requiring complex simulations.Peng H. and Bai, X. [1] show that a Support Vector Machine (SVM) is a promising candidate to improve the accuracy of orbit prediction, especially for Earth satellites. In this paper, we extend this approach to the Rosetta mission, enhancing its orbit prediction. We introduce AI4POD (Artificial Intelligence for Precise Orbit Determination), a software package that combines classical orbit determination methods with modern ML techniques. AI4POD includes several tools for conducting orbit predictions and determinations and features a comprehensive force model that incorporates various forces, such as spherical harmonics for gravity field modeling, third-body perturbations, solar radiation pressure, atmospheric drag, and more.We simulate the orbit of the Rosetta spacecraft around the comet 67P/Churyumov-Gerasimenko and compare it to real mission data [2, 3]. Orbital parameters can be determined using Weighted Least Squares (WLS) estimation or a Kalman filter. The SVM algorithm is implemented alongside other tools to learn the generalized error of the simulation, thereby improving the accuracy of orbit prediction.AcknowledgementsThe project Artificial Intelligence for Precise Orbit Determination (AI4POD) is funded by Deutsches Zentrum für Luft- und Raumfahrt, Bonn-Oberkassel, under grant 50LZ2308.References[1] Peng, H., Bai, X. Machine Learning Approach to Improve Satellite Orbit Prediction Accuracy Using Publicly Available Data. J Astronaut Sci 67, 762–793 (2020). https://doi.org/10.1007/s40295-019-00158-3[2] Andert, T., Aigner, B., Dallinger, F., Haser, B., Pätzold, M., and Hahn, M.: Comparative Analysis of Data Preprocessing Methods for Precise Orbit Determination, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19558,https://doi.org/10.5194/egusphere-egu24-19558[3] Pätzold, M., Andert, T.P., Hahn, M., Barriot, J.-P., Asmar, S.W., Häusler, B., Bird, M.K., Tellmann, S., Oschlisniok, J., Peter, K., 2018. The nucleus of comet 67P/Churyumov-Gerasimenko - Part I: The global view – nucleus mass, mass loss, porosity and implications. Monthly Notices of the Royal Astronomical Society. https://doi.org/10.1093/mnras/sty317
Exploring the Dynamics of Debris Disks through Vertical Thickness Analysis: Case Study of HD32297
Authors: Luppe Patricia
Published: July 2024

Debris disks are circumstellar disks made of dust and rocky material that orbit stars. In the Solar System, the Asteroid and Kuiper Belt are debris disks similar to the ones we observe around other stars. Debris disks provide valuable insights into planetary system dynamics that complement findings from planet and protoplanetary disc studies. Our research probes the implications of the vertical profile shape on the characteristics of the debris disk environment, with a specific focus on the intriguing case of HD 32297. One key aspect of our research is the differentiation between the influences of planets, flyby stars and large planetesimals on the vertical shape of debris disks. By understanding these distinct influences, we can gain a deeper understanding of the dynamics of these systems.We present a multi-wavelength analysis of HD 32297's edge-on debris disk, a well-known disk orbiting a young A star. This system exhibits one of the largest infrared excesses observed among main-sequence stars. HD 32297's disk is highly edge-on and very narrow in mm-dust, so it is one of the best disks to examine the vertical structure profile.Our high-resolution data enable us to measure the disk's vertical thickness for different radii and, therefore, to create a vertical thickness profile along the radial direction. This makes the system an excellent test bed, allowing us to examine various dynamical models for debris disk interactions.
High-Priority Mafic Mineral-Bearing Science Targets at the Artemis III Candidate Landing Regions
Authors: Moriarty Daniel , Petro Noah
Published: July 2024

The lunar south pole is a region of focused scientific and exploration interest, with several crewed and robotic missions to this region planned within the next decade.   Understanding the mineralogy of the region is essential to inform landing site characterization and selection and provides key context for interpreting samples and in situ observations.The Artemis exploration zone (areas poleward of 84° latitude) is also relevant to geological investigations providing new insight into fundamental planetary processes.  Specifically, Artemis Science Objective 1 from the Artemis III Science Definition Team Report is to understand a wide range of planetary processes including formation and differentiation of the Moon into a core, mantle, and crust, in addition to subsequent processes such as volcanism, tectonism, impacts, and regolith development. Artemis astronauts will address these objectives in several ways, guided by compositional remote sensing analyses of the region.  Here, we present local mineralogical and compositional analyses of candidate high-priority science targets drawing upon several remote sensing datasets including Moon Mineralogy Mapper data. Moon Mineralogy Mapper (M3) data provide the highest spatial - and spectral-resolution mineralogical data for the lunar surface and are therefore ideally suited for characterizing compositional diversity at ~100 m spatial scale. Mineralogical diversity across the lunar surface is dominated by variations in the abundance and composition of a handful of common lunar minerals and oxides, including plagioclase, pyroxene, olivine, spinel, and ilmenite.  This diversity is reflected in overall albedo and differing strengths and relative positions of spectral absorption bands at 1 and 2 μm. M3 achieved near-complete coverage of the south polar region. Due to the pole-crossing orbit of Chandraayan-1, areas close to the pole were imaged numerous times across the lifetime of the M3 mission, with different lighting conditions and orbital altitudes.  This is helpful, as lighting conditions at high latitudes involve extreme solar incident angles and large shadows, affecting data quality (signal-to-noise ratio) and availability. The number of M3 observations available for each candidate Artemis III region is given in Table 1.  In this work, we examine the character and mineralogical diversity reflected full-resolution M3 data for the candidate Artemis III landing regions.Fig. 1: M3 1 μm Integrated Band Depth across the Artemis Exploration Zone.  Areas lacking well-illuminated M3 pixels (in global mosaics) are shaded light grey.  Note: these areas may be illuminated in individual M3 images.
Quantum Technologies for Planetary Geodesy
Authors: Woerner Lisa
Published: July 2024

Quantum Technologies have been rising in the past years. With commercial interest on the rise and finished products being made available, quantum-based gravitational field measurements are the first real-life application.To realize a quantum gravimeter or a quantum gradiometer, here, atom interferometers are discussed. Atom interferometers function by subjecting a cloud of atoms to three successive laser beams. Due to the mass of the atoms, they are subject to outside accelerations. The effect of the acceleration is then seen in the phaseshift of the interferometeric signal in the readout ports. The achievable precission of the measurement is determined by the stability of the laser gratings and the temperature of the underlying atom ensemble. Consequently, the atom cloud is typically cooled to improve the measurement and the obtained signal. Following that line of reasoning, atom interferometers allow for very precise and drift free measurements. This gives a strong advantage over classical systems, which always include residual friction and thereby drift in the measurement.In this talk, I will give an overview over the state of the art of cold atoms in space and especially the most recent developments in Earth observation. I will then follow this up by discussing the opportunities of atom interferometers in planetary exploration with specific regards to underlying structures, (seasonal) changes, and planetary dynamics.To illustrate the advantages, I will present the MaQuIs proposal, which is concerned with Mars and its gravitational field. In doing so, I will also cover the advantages and limitations of cold atom systems and hybridization concepts available to improve the signals.
The generation and evolution of dust particles through collision ofIDPs in the Saturn system
Authors: Moura Vanessa , Sfair Rafael , Buzzatto Patricia
Published: July 2024

Saturn is known for its extensive and complex ring system. In many cases, the origin and evolution this structure are closely linked to interactions with satellites. These satellites can produce material capable of populating the rings through particle generation by collision of interplanetary projectiles (IDPs) with their surfaces. The amount of particles generated is related to the flux of projectiles. These IDPs originate from various sources such as comets and objects from the Kuiper Belt and the flux of these objects is usually estimated from measurements made by the space probes. After being ejected, the particles are influenced by many forces: gravitational (both from the planet and the satellites), oblateness, electromagnetic, solar radiation and plasma drag.In this study, we propose to analyze the dust generation from Saturn’s satellites, by computing the amount of dust generated by each satellite through the flux of IDPs. We will also compare the dust production rate for each Saturn’s family, taking into account recently discovered satellites to further analyze the mechanisms of transport and fate of the particles. We validated our code using the results from Sfair & Giuliatti Winter (2012) and from the data obtained, we have observed that the dust production rate is directly proportional to the radius of the satellite.We selected two satellites of Gallic family to illustrate our results. Albiorix which has a radius of approximately 13 km and produces 1.41 × 10−1 gs−1 of dust, while Bebhionn has a radius of 3 km and produces a rate of 7.40 × 10−3 gs−1, these are the extreme values we found for this family. Analyzing other cases, we see that the satellite that produces the most dust in the Inuit group is Sianarq, with a rate of 2.04 × 10−1 gs−1, and in the Nordic group is Ymir, with a production of5.66 × 10−2 gs−1.Subsequently, we are analyzing the evolution of these dust particle shortly after they are ejected from the satellites. Analyzing previous studies on the ejection of dust particles from Iapetus and Phoebe, we know that the particles ejected from the satellites, under the influence of oblateness force, electromagnetic force, solar radiation, and plasma drag, are transported close to the planet due to the influence of solar radiation force, resulting in potential collisions with the satellites and the planet. In our case, we detected collisions with Enceladus, Tethys, Dione, Rhea, Titan, Janus, Telesto ans with the planet itself (approximately 90% of the collisions). By integrating solar tidal effects into our study, we intend to examine how this force influences the particles.
Latitudinal Variation in Internal Heat Flux in Jupiter's Atmosphere: Effect on Weather Layer Dynamics
Authors: Hu Xinmiao , Read Peter
Published: July 2024

Conventional weather layer General Circulation Models (GCMs) typically simulate over a height range extending only a short distance beneath the water cloud base, constrained by computational resources. Due to the limited knowledge about the environment at depth, the conditions specified at the bottom boundary of the domain are usually greatly simplified. Consequently, the influence of deeper atmospheric dynamics on cloud-level phenomena remains poorly understood. Recent observations from the Juno mission have provided new insights into the complex conditions prevailing within Jupiter's deep atmosphere. Given these advances, it is timely to re-evaluate the simple assumptions regarding the deep atmosphere currently employed in weather layer GCMs.In this study, we challenge the conventional approach by introducing latitudinal variations in internal heat flux into a GCM of Jupiter’s atmosphere. Our model incorporates a heat flux profile that decreases from the equator to the poles, with additional complexities such as belt-and-zone contrast and hemispheric asymmetry. Preliminary results show significant deviations in weather layer atmospheric dynamics when compared to constant flux models, particularly in the equatorial regions. We discuss the underlying mechanisms driving these differences, providing insights into the coupling between Jupiter's visible weather layer and its obscured deeper layers. This work represents a step towards developing a more comprehensive GCM for Jupiter, which could also enhance our understanding of other giant planets, by incorporating more realistic conditions at the bottom boundary.
Mars – Ion and Neutral Energy Analyser: A new instrumental concept to characterize Mars’ upper atmosphere
Authors: Steichen Valentin , Leblanc François , Berthelier Jean-Jacques , Guignan Gabriel , Ferreira Frederic
Published: July 2024

The “Mars Magnetosphere ATmosphere Ionosphere and Space-weather SciencE (M-MATISSE)” mission is an ESA Medium class (M7) candidate currently in Phase-A study by ESA. M-MATISSE main scientific goal is to unravel the complex and dynamic couplings of the magnetosphere, ionosphere and thermosphere (MIT coupling) with relation to the Solar Wind (i.e. space weather) and the lower atmosphere of Mars. Among the set of instruments present onboard the platform, the Mars – Ion and Neutral Energy Analyzer (M – INEA) is an energy spectrograph and mass spectrometer specifically designed to image the low energy range of the neutral particles’ energy distribution (