bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of nonlinear tide-surge interaction in the Pearl River Estuary during Typhoon Nida (2016)
Authors: Huang Linxu , Zhang Tianyu , Zhang Shouwen , Wang Hui
Published: July 2024

Abstract. Storm surge is one of the most significant marine dynamic disasters affecting the coastal areas worldwide. An in-depth study of its mechanisms is crucial for improving forecasting skills and implementing better prevention measures. In this study, a numerical model based on the Advanced Circulation Model (ADCIRC) was used to investigate the characteristics of storm surges and the mechanisms of tide-surge interaction in the Pearl River Estuary (PRE) during Typhoon Nida (2016). Three different types of model runs were conducted to distinguish water level variations caused by astronomical tides, storm surges, and tide-surge interactions. The results indicated that storm surges are primarily modulated by tides through tide-surge interactions. The nonlinear effect is mainly generated by the nonlinear local acceleration term and convection term from the tide-surge interactions in the study area. However, they are predominantly governed by the nonlinear wind stress term and bottom friction term in shallow water regions such as the northern part of Qi’ao Island and Shenzhen Bay. Additionally, variations in the y component of the nonlinear momentum terms are more significant than those in the x component. To investigate the impact of tidal phase on surge response to Typhoon Nida, we altered the landfall timing to introduce variations in PRE characteristics. The results shows that the contribution ratio of each nonlinear term changes little, their magnitudes fluctuate depending on the timing of landfall.
Observation of plasma interaction with Lunar surface and near-surface environment: Science case for Lunar Neutrals Telescope on Turkish Lunar Mission AYAP-
Authors: Shimoyama Manabu , Karlsson Stefan , Barabash Stas , Futaana Yoshifumi , Wieser Martin , Yalioglu Burak , Karagözoğlu Burak , Öztürk Fahri
Published: July 2024

Solar wind precipitation on atmosphere-less bodies like the Moon generates backscattered and sputtered energetic neutral atoms (ENAs) from the surface and near-surface environment. Since ENAs does not sense electromagnetic fields, ENAs can be assumed to retain the initial velocity if gravity effect can be ignored. This makes global remote sensing of surface properties and near-surface environment possible from an orbiting spacecraft. Lunar Neutrals Telescope (LNT) is an ENA instrument onboard the first Turkish Lunar Mission AYAP-1 [1], which is planned to be launched in 2026. The LNT is designed to measure energetic neutral atoms generated at the Moon surface from the orbiting spacecraft around the Moon and make a global map of plasma precipitation onto the Moon surface. There are three major scientific objectives for LNT observations: (A) To investigate the structure (shape) of mini-magnetosphere created by lunar magnetic anomalies and its response to the solar wind, (B) to search for volatile-rich areas on the Moon’s surface with the special focus on permanently shadowed regions, and (C) to investigate the formation and maintenance processes of the lunar exosphere.

Figure 1. Cutaway view of LNT instrument
The Design of the LNT, as shown in Figure 1, is based on the successful predecessor CENA/SARA sensor on Chandrayaan-1 [2] and is updated to achieve unprecedentedly high angular resolution (∼7° × 7°), which is approximately factor of 7 higher than the predecessor. Owing to its high angular resolution, the expected spatial resolution at the Lunar surface is ~12 km, which is small enough to resolve the fine structure of the mini-magnetosphere and properties of the permanently shadowed regions. The predicted performance of LNT is shown in the Table I. Energy and mass resolution of LNT also allows us to discriminate the process of plasma interaction with the surface (i.e. backscattered or sputtered) from which information of surface properties can be derived.
We will present the predicted performance of LNT with the current status of development and discuss the expected sciences by LNT observations.
Table I. Predicted performance of LNT

References:
[1] B. Yağlioğlu, et al. (2023), "The First Turkish Lunar Mission Part 1: Programmatic, Mission and System Aspects," 2023 10th International Conference on Recent Advances in Air and Space Technologies (RAST), Istanbul, Turkiye, 2023, pp. 1-6, doi: 10.1109/RAST57548.2023.10197907.
[2] M. Wieser et al. (2010), First observation of a mini-magnetosphere above a lunar magnetic anomaly using energetic neutral atoms, Geophys. Res. Lett., 37, L05103, doi:10.1029/2009GL041721.
Twinkle: a satellite spectroscopy mission for the next phase of exoplanet science
Authors: Raman Mohan Yoga Barrathwaj , Wilcock Benjamin , Stotesbury Ian , Tessenyi Marcell , Archer Richard , Ma Sushuang , Bradley Lawrence , Edwards Billy , Tinetti Giovanna , Tennyson Jonathan , Savini Giorgio , Windred Philip , Al-Refaie Ahmed
Published: July 2024

The Twinkle telescope is a space-based observatory conceived to study solar system objects, exoplanets, brown dwarfs, protoplanetary disks and stars. The satellite is based on a high-heritage platform and will carry a visible and infrared spectrograph providing simultaneous broad wavelength coverage. Launching into a Sun-synchronous low-Earth polar orbit, Twinkle will operate from a highly stable thermal environment for a baseline lifetime of seven years.In this presentation, the Twinkle team will provide the latest updates on the mission and will highlight the work undertaken by the Founding Members of the extrasolar survey, showcasing the many initial science themes under development. Focusing on the objectives, scientific justification, and high-level observation plan we will explore how Twinkle will contribute to a broad range of astrophysics research.Additionally, we explore the observational programme being developed to provide both initial characterisation and simultaneous ground and space-based observations, demonstrating how Twinkle’s broad spectral coverage can be complementary across multiple ground and space-based telescopes.
Source of Mercury’s Hollow-Forming Materials: Preliminary Results from Geological Mapping, Spectra, and Impact Simulations
Authors: Wright Jack , Caminiti Emma , Rae Auriol , Besse Sébastien
Published: July 2024

Mercury has a large core, but paradoxically the surface is also volatile rich. Most core-enlarging scenarios envisaged for Mercury would have heated the silicates and preferentially driven-off these volatiles. Mercury’s hollows, flat floored, rimless depressions tens of metres deep and up to tens of kilometres across, appear to have formed by the loss of some volatile material to space upon its exposure at the surface, often by impact craters. Hollows lack superposing craters, indicating that they may be undergoing active formation today. The subsurface distribution of Mercury’s hollow-forming material is not known. If confined to the upper few kilometres of Mercury’s crust, sampled by the craters up to a few hundred kilometres in diameter in which most hollows are found, then perhaps it was accreted as a late veneer after the core-enlarging event. Alternatively, if the hollow-forming material is present throughout a greater thickness of Mercury’s silicate portion then the timing of any high-temperature core-enlarging event must have taken place very early in the planet’s history to allow time for a volatile-rich silicate fraction to reaccrete. Here, we study the Caloris basin: Mercury’s largest, well-preserved impact structure. We employed a combination of geological mapping, reflectance spectroscopy, and numerical impact simulations to map the present-day distribution of the hollow-forming material in Caloris ejecta, preserved as hummocky plains hosting km-scale knobs, back to its pre-Caloris, subsurface distribution. Our results suggest that Mercury’s hollow forming material comes from the whole thickness of the crust, a deeper constraint than previous studies.
The dense resonance meshes around the ringed Chariklo, Haumea and Quaoar
Authors: Sicardy Bruno , Salo Heikki
Published: July 2024

We consider the effect of Spin-Orbit Resonances (SORs) excited on ring particles by bodies with non-axisymmetric gravitational fields. SORs happen for n/Ω ~ m/(m-j) , where n is the mean motion of the ring particles, Ω is the spin rate of the body, m is an integer (positive or negative) and j>0 is the order of the SOR. Due to the structure of their phase portraits, only first- and second-order SORs are expected to significantly excite eccentricities on dense collisional rings.
We calculate more specifically the eccentricities excited at SORs around Chariklo, Haumea and Quaoar, considering in turn the effects of their triaxiality and the effects of a mass anomaly μ=10-3  relative to the mass of the central body. The triaxiality is obtained from stellar occultation results, while μ=10-3 is a typical estimated value corresponding to topographic features (mountains, depressions,...) of several kilometers in height or depth. The results are displayed in Figs. 1, 2 and 3, corresponding respectiveley to Chariklo, Haumea and Quaoar. We find that the triaxialities of all three bodies excite large eccentricities (e>0.1) on the ring particles, resulting in unstable orbits that suffer strong torques from the SORs, chaoticity due to the superimposition of SORs, or even short-term physical collisions with the body.
As a consequence, all the region inside the 1/2 (or 2/4) SOR is not prone to host stable rings around Chariklo and Haumea. Moving outward, the 1/3 SOR excites moderate eccentrities of the order of e=0 01 on the particles of Chariklo's and Haumea's rings, thus avoiding a rapid destruction of these rings. In the case of Quaoar, the 1/3  and 5/7 SORs excite eccentricities of a few 10-3 only, preventing again a rapid ring destruction.
A companion paper by Salo and Sicardy presents N-body simulations showing that the 1/3 second-order SOR can indeed cause a single-sided confinement, thus explaining the current location of the main rings of Chariklo, Haumea and Quaoar. More simulations are required to explore the stability of the second ring of Quaoar (Q2R) that orbits near the 5/7 second-order SOR. This resonance is surrounded by strong first-order SORs (Fig. 3) that may destabilize Q2R. A better assessment of Quaoar's triaxial shape and mass anomaly μ must be now undertaken for discussing further the stability of this ring.
Acknowledgments. BS thanks the French ANR “ROCHE" for support.
 
Fig. 1 - Eccentricities forced on a particle with an initially circular orbit around Chariklo. Left: first-order SORs, red: resonances forced by the triaxial shape of Chariklo, black: resonances forced by a mass anomaly of μ=10-3. Right: second-order resonances, blue: effect of the triaxial shape of Chariklo, black: effect of a mass anomaly μ=10-3.

Fig. 2 - The same as Fig. 1 for Haumea.

Fig. 3 - The same as Fig. 1 for Quaoar.
The Dragonfly New Frontiers Mission to Titan
Authors: Lorenz Ralph ,   Dragonfly Team
Published: July 2024

Saturn's giant moon Titan has been revealed to be remarkably Earth-like, with a landscape of vast dunefields, river channels and lakes under a smoggy  sky punctuated by methane downpours. Titan serves as a frigid laboratory in which the same processes that shape our own planet can be seen in action under exotic conditions. Titan has a rich inventory of complex organic molecules that may provide clues how the building blocks of life are assembled.Exploring such a scientifically rich environment demands mobility, so that diverse sites can be visited, and particular interactions, such as those between liquid water from impact crater melt with organics, investigated. Fortunately, Titan’s low gravity and dense atmosphere means that aerial mobility is easy to accomplish: rotorcraft on Titan have been proposed even 20 years ago.In 2019 NASA selected the Johns Hopkins Applied Physics Lab’s Dragonfly as its 4th New Frontiers mission.  Dragonfly is a relocatable lander, an octocopter powered by a radioisotope thermoelectric generator which provides heat – valuable in Titan’s frigid (94K) environment – as well as electricity. Dragonfly – roughly the size of the Perseverance rover – carries a formidable scientific payload and will fly, using a large battery trickle-charged by the generator, for about 30 minutes every couple of Titan days (i.e. about once a month), covering several kilometers in each hop.Initially landing in the dunefields nearby, it will traverse to the 80km Selk impact crater, making geomorphological, meteorological and even seismological investigations over more than 3 years.  I will discuss the transformative scientific opportunities of this mission, some of the technical innovations that make it possible, and the project’s current status.  In April 2024 NASA confirmed the Dragonfly project development for a 2028 launch and arrival in 2034, one Titan year after the Huygens probe descent, information from which allows definition of the winds and atmospheric environment to be encountered. 
VRExplorer an immersive and collaborative tool to multiply field trip experiences
Authors: Civet François , Clarke Lionel , Vandergucht David , Bertrand Guillaume , Costard Kevin , Clochez Charlotte
Published: July 2024

VRExplorerThis software is an immersive and collaborative tool allowing visualization and analysis of planetary terrains. This tool has been developed for education of the new generation of geoscientists to improve the comprehension of planetary terrains. After several months of deployment, VRExplorer already shows a huge potential both for students and researchers. The software is based on a cloud platform on which users can upload their dataset, using standard formats used by the geoscience community: digital terrain models, meshes, and point clouds. It creates the virtual scenes automatically and share the tiles to remote users in real time up to the native resolution of the dataset. Connecting to the application, users can see and talk to each other, they can navigate over the terrains stored on the server using both virtual reality headsets and classical computers.A cloud-based storageThe web-platform allows users to upload GeoTIFs satellite images to create regional context of areas of interest. It reads the metadata of images providing an absolute geographic reference for each virtual scene based on the projection information of inputs. Virtual terrains are then processed using both topographical (DTM) and texture (orthoimages). Users can also upload meshes in 3DTiles format (Standard from Open Geospatial consortium). This specific file format enables to store and share massive meshes preserving the initial resolution of the data and the geographic reference.The result is a fusion of massive datasets shared to multiple users.A tool for teaching geosciencesVRExplorer is already used in several universities and aims at becoming a reference for virtual pedagogy on unreachable terrains.For teachers, this tool is used to:- Easily share and explore geodata-rich scenes of various kind,- Create courses and assessments into the virtual scene,- Gather records of user experiences, measurements created by users, and answers to course sessions for post course analysis.For students, it’s a ludo-educative tool providing emotional experiences which are well-known to be a multiplier in the process of understanding and memorization.  
Kinetic Field Theory Applied to Planetesimal Formation I: Freely Streaming Dust Particles
Authors: Shi Jiahan , Bartelmann Matthias , Klahr Hubert , Dullemond Cornelis
Published: July 2024

Planet formation in the solar system was started when the first planetesimals were formed from the gravitational collapse of pebble clouds. Numerical simulations of this process, especially in the framework of streaming instability, produce various power laws for the initial mass function for planetesimals. Despite the importance of this process we still are lacking a theoretical concept how to translate turbulence characteristics into the statistical properties of particle clusters, and the resulting mass function for planetesimals. Recently, a kinetic field theory for ensembles of point-like classical particles in or out of equilibrium has been applied to cosmic structure formation. This theory encodes the dynamics of a classical particle ensemble by a generating functional specified by the initial probability distribution of particles in phase space and their equations of motion. Here, we apply kinetic field theory to planetesimal formation. A model for the initial probability distribution of dust particles in phase space is obtained from a quasi-initial state for a three-dimensional streaming-instability simulation that is a particle distribution with velocities for gas and particles from the Nakagawa relations. The equations of motion are chosen for the simplest case of freely streaming particles. We calculate the non-linearly evolved density power spectrum of dust particles and find that it develops a universal $k^{-3}$ tail at small scales, suggesting scale-invariant structure formation below a characteristic and time-dependent length scale. Thus, the KFT analysis indicates that the initial state for streaming instability simulations does not impose a constraint on structure evolution during planetesimal formation.
Investigating Mercury's Magnetotail Twist at the Orbits of MPO and Mio
Authors: Exner Willi , Romanelli Norberto
Published: July 2024

MESSENGER observations of Mercury's tail twist reveal a rather small twist of up to 3 degrees.In this study, we model Mercury's magnetotail response to different Interplanetary Magnetic Field (IMF) directions and address what MPO and Mio might observe in their orbital phase. Our hybrid model results indicate that Mercury's magnetotail topology exhibits a similar small twist at MPO altitudes, comparable to MESSENGER results.In contrast, our results suggest that further downtail, Mio's tail twist observations are strongly dependent on the upstream magnetic field direction .While the tail twist morphology appear to be mostly symmetric  to each other, magnetospheric plasma exerts an additional influence on the current sheet that breaks some symmetries.Using different analysis techniques, we estimate the degree of tail twisting predicted by these simulations. 
 Life-Earth coevolution: the role of phosphorus in Archean oxygen accumulation 
Authors: Cañadas Blasco Fuencisla , Guilbaud Romain , Fralick Philip , Xiong Yijun , Poulton Simon W. , Martin Redondo Mari-Paz , G. Fairén Alberto
Published: July 2024

Investigating the presence of oxygen on planets within our solar system and beyond is crucial for understanding the potential for life beyond Earth. Oxygen is a key ingredient for life as we know it and serves as a key indicator of habitability and planetary processes [1]. On Earth, the first lasting rise in atmospheric oxygen started ∼2.4 billion years ago and was a crucial process that fundamentally transformed the planet's atmosphere and oceans, leading to the evolution of complex life forms. However, geochemical evidence reveals the existence of intermittent oxic whiffs before that period, although the mechanisms that drove the production of such early oxygen are poorly constrained. Here, we present redox sensitive trace metal and Fe speciation data, as well as phosphorus phase partitioning results, for a 2.94 billion-year-old drill core from the Red Lake area, Canada. Results suggest dynamic oceanic Fe cycling between ferruginous conditions (anoxic Fe-rich), euxinic (anoxic S-rich) and short-lived episodes of oxygenated waters consistent with depleted (
Experimental results from the CoPhyLab – determination of the mass loss balance
Authors: Meier Gerwin , Kreuzig Christopher , Blum Jürgen
Published: July 2024

Water is the driving force of life as we know it. Therefore, it is essential to study its properties and behaviour in various environments. In outer space, water occurs, e.g., in comets. Measurements on comets are challenging and expensive. Thus, it is easier to simulate the environment of outer space in the laboratory.One laboratory where this environment can be simulated is the Comet Physics Laboratory (CoPhyLab) at the TU Braunschweig. Outer space is simulated with a thermal vacuum chamber enabling pressures as low as 10−6mbar and temperatures of around 100 K. Insolation, either permanent or following a diurnal cycle, can be simulated via a focused halogen lamp and rotating shutter blades. With this setup, the most abundant ingredients of comets, i.e. granular water ice and dust, can be studied in their natural environment and repetitive measurements can be performed.One observed property of comets, which is not yet fully understood on a physical basis, is the ejection of dust particles due when approaching the sun. In the CoPhyLab, this dust activity can be quantitatively measured by the difference of total mass loss and mass loss by ice sublimation alone. The latter can be measured with a mass spectrometer and can, furthermore, be inferred from the surface temperature measured by an infrared camera and using the Hertz-Knudsen equation for the sublimation of water ice. The total mass loss of the sample on the other hand can either be measured by using a scale or by measuring the shrinking volume of the sample via a line laser system. The combination of all instruments determines the ratio of mass loss in gas and particles and its evolution over time.The latest results on the dust and gas activity of granular ice samples under different illumination conditions will be presented, from which ideas of the enigmatic dust-emission mechanism can be formulated.
Exoplanet observations at the Instituto de Astrofísica de Canarias IAC and its collaboration with the ExoClock project
Authors: Libotte Florence , Fernández-Rodríguez Gareb Enoc
Published: July 2024

IntroductionA group of amateur astronomers from the Sabadell Astronomical Society is using small professional telescopes to obtain exoplanets transits photometry for the ExoClock project and ARIEL mission. Contact was taken in 2022 with MuSCAT2 team who uses the Carlos Sánchez Telescope, a telescope of 1.50 m diameter, almost fully dedicated to exoplanet, located in Tenerife. It appeared than that some exoplanet targets were common to MuSCAT2 investigations and ExoClock exoplanet database. This talk will explain how both shared a large number of past transits. As a result, all MuSCAT2 team has been included as co-authors to the IV ExoClock transit data release MuSCAT2 and Carlos Sánchez Telescope projectFirst, The MuSCAT2 camera, will be described, it allows to obtain simultaneous four channels of observations. It is mounted on the Carlos Sánchez Telescope. The main purpose of MuSCAT2 team is to validate or not the exoplanet candidates published by TESS mission. Once it is validated, the group means to characterize the main parameters of the exoplanet like, radius, mass but also other characteristics.ExoClock missionExoClock purpose is to bring correct ephemeris of interesting exoplanets for the ARIEL space mission, to be launched in 2029. This mission will study exoplanets atmospheres. Collaboration developmentAround a hundred of targets are common to both projects. The process to adapt MuSCAT2 transits files to ExoClock database is explained. This was done by a student, Gareb Enoc Fernández Rodríguez, from La Laguna University, with Enric Pallé as a mentor.The TCS transits information has a specific format, not compatible with ExoClock database, so it was necessary to develop a “pipeline” to do this job. For that, contacts with Angelos from ExoClock were key.As amateur, I belong to MuSCAT2 team and I observe on the TCS regularly, together with students and professional astronomers. I will describe briefly how the work is organized and what is my job in the collaboration between the IAC, TCS and ExoClock.
Evaporated atmosphere in the interplanetary medium of early-type stars
Authors: Lehtmets Alexandra , Kama Mihkel , Aret Anna , Fossati Luca
Published: July 2024

In our study, we investigate how early-type stars influence the gases escaping from exoplanet atmospheres into space. We focus on two key aspects: how the star's radiation force and gravity affect the path of these gases, and how fast neutral atoms speed up before changing into ions. By combining theories and models, we aim to understand these processes better. Our research not only deepens our understanding of exoplanets but also sheds light on their relationship with the stars they orbit. Additionally, our models could help predict which chemical elements end up accreting on to the host star. For early-type stars, our predictions might even show up as observable patterns in their spectra, because one of the unique features of early-type stars is that material accreting onto them can easily “pollute” the photosphere. 

 
 

 

 

 
 
Determination of physical parameters of asteroids based on data from space and ground-based telescopes.
Authors: Najda Kacper , Podlewska-Gaca Edyta , Bartczak Przemysław , Takacs Nora , Kiss Csaba , Bosh Josep M , Kamiński Krzysztof , Kamińska Monika , Polińska Magdalena
Published: July 2024

The aim of the project is to create spin and shape models of selected main belt asteroids based on dense ground-based lightcurves and  the data from space missions. Research on asteroids is important for understanding the origin and evolution of the whole Solar System. Studying them will allow us to better understand the nature of asteroids. Knowledge of the physical properties of asteroids will also facilitate future space mining. The basis for creating asteroid models are the photomrtric lightcurves, which allows for the determination of various asteroid parameters. The data used to create these brightness changes come from observations conducted by both: professional  astronomers and amateurs. Such collaboration enables the accumulation of large amounts of data necessary for modeling. Ground-based observations are also supplemented by data from space missions like TESS anf Gaia.  The main modeling tool is the SAGE program, developed in the Astronomical Observatory Institute at Adam Mickiewicz University. Using genetic algorithm it enables to create non-convex spin and shape model for asteroids basing solely on lightcurves. The first source of data is photometric observations of asteroids made by amateur astronomers, who submit the raw observations to the GaiaGOSA  service. Another source is data from the Roman Baranowski Telescope (RBT) located in Arizona, obtained by professional astronomers. To create an accurate model, the data from multiple  opositions  are necessary. Gathered observations display the view of asteroids from different phase angles and  ecliptic coordinates. Thanks to this we observe the amount of light incoming from different geometrical orientation of the object. Using advanced genetic algorithm SAGE(Dudziński, & Bartczak, 2018) calculates a good approximation of the three-dimensional shape of the asteroid, as well as its rotation period and the orientation of the rotation axis (pole position). We have created the models for large main belt asteroids. Thanks to long and dense lightcurves from TESS mission we were able to determine  spin orientation and precise shapes of the asteroids. Moreover, the sparse data from Gaia mission allowed to determine the proper size of asteroids along rotation axis. We are presenting here the results for 59 Elpis, 96 Aegle and 134 Sophrosyne. In Fig. 1 we show the calculated shape of 96 Aegle. In the near future precise models for next objects will be determined.Fig 1: Calculated shape model for 96 Aegle.Bartczak, P. ; Dudziński, G. , "Shaping asteroid models using genetic evolution (SAGE)", 2018, Monthly Notices of the Royal Astronomical Society, Volume 473, Issue 4, p.5050-5
Possible gas-phase formation routes of dimethyl sulfide in extraterrestrial environments
Authors: Di Genova Gabriella , Giustini Andrea , Mancini Luca , Rosi Marzio , Ceccarelli Cecilia , Balucani Nadia
Published: July 2024

The presence of dimethyl sulfide (DMS) in the atmosphere of exoplanets has been invoked as a potential biosignature since its presence atmosphere of Earth has a biological origin. Dimethylsulfoniopropionate (DMSP) is produced by phytoplankton and then degraded to form methanethiol (CH3SH) and DMS. Microbial methylation and detoxification processes can also produce DMS from hydrogen sulfide H2S.Recently, a tentative detection of DMS on the candidate Hycean exoplanet K2-18 b was reported in the work by Madhusudhan et al. [1]. Dimethyl sulfide is also detected in the coma of comet 67P/Churyumov-Gerasimenko [2], and its isomers ethyl mercaptan, CH3CH2SH, has been detected toward Orion KL [3]. Therefore, DMS adds to the list of S-bearing molecules identified at the moment in the extraterrestrial environment.No formation routes of extraterrestrial DMS are reported in the literature at the moment. Therefore, we have started a systematic theoretical investigation to unveil the possible formation mechanisms of DMS in the gas phase. We make use of electronic structure calculations of the relevant potential energy surfaces and kinetics calculations to derive the energy profile and rate coefficients of each proposed reaction following the same schemes that we have previously identified for the formation of the analogous O-bearing species dimethyl ether [4]. [1] Madhusudhan, Nikku, et al. "Carbon-bearing molecules in a possible hycean atmosphere." The Astrophysical Journal Letters 956.1 (2023): L13.[2] Hänni, N., et al. "Identification and characterization of a new ensemble of cometary organic molecules." Nature Communications 13.1 (2022): 3639.[3] Kolesniková, Lucie, et al. "Spectroscopic characterization and detection of ethyl mercaptan in orion." The Astrophysical Journal Letters 784.1 (2014): L7.[4] Skouteris, Dimitrios, et al. "Interstellar dimethyl ether gas-phase formation: a quantum chemistry and kinetics study." Monthly Notices of the Royal Astronomical Society 482.3 (2019): 3567-3575.
Double Trouble: Polarimetric Insights into the Didymos-Dimorphos post-DART Evolution
Authors: Gray Zuri
Published: July 2024

On September 26, 2022, the NASA DART (Double Asteroid Redirection Test) spacecraft struck Dimorphos, the moonlet of Didymos, to test near-Earth object deflection through impact in the context of planetary defence (Daly et al. 2023). As well as causing a change in Dimorphos’ orbital period (Thomas et al. 2023), the impact caused a massive dust cloud to be ejected from the surface (e.g. Li et al. 2023; Opitom et al. 2023). By studying the characteristics and behaviour of the ejecta cloud, the DART mission provided a rare opportunity to peer under the surface of an asteroid and further our understanding of their global properties.Didymos-Dimorphos was monitored in polarimetric mode before and after the impact (Bagnulo et al. 2023; Gray et al. 2024). The post-impact measurements revealed a significant drop in polarisation, suggesting differences between the material in the ejecta and that on the original regolith surface. Remarkably, even months after the impact, the polarisation remained persistently lower than pre-impact, despite photometric measurements showing that the system faded back to its “normal” brightness around 23 days post-impact (Graykowski et al. 2023). This suggests the presence of residual ejecta material still within the system months after the impact, either in orbit or deposited on the asteroid surface(s). This contrast in findings demonstrates the sensitivity of polarimetric measurements, revealing details often unattainable from traditional observations techniques.In this presentation, we will be discussing these previous results, as well as presenting new polarimetric measurements obtained with VLT this year. In 2024, Didymos-Dimorphos is making another close approach to Earth, offering an opportunity to study the system around two years after the DART impact. Our goal with these observations is to establish whether the polarisation of the system has returned to the pre-impact level or remains at a lower level as observed post-impact and, thus, clarify if or how much ejecta material has remained in the system. This may ultimately benefit the Hera team (Michel et al. 2018) for planning the spacecraft trajectory to avoid damage by impacts of dust particles. Eventually, instruments on board Hera will reveal the spatial distribution of fresh material on the surfaces of the system. This unique opportunity will allow us to test and demonstrate the reliability and importance of polarimetric measurements of small solar system bodies.Daly, R., et al. (2023), Natur, 616, 443; Thomas, C. A., et al. (2023), Natur, 616, 448; Li, J.-Y., et al. (2023), Natur, 616, 452; Opitom, C., et al. (2023), A&A, 671, L11; Bagnulo, S., et al. (2023), ApJL, 945, L38; Gray, Z., et al. (2024), PSJ, 5, 18; Graykowski, A., et al. (2024), Natur, 616, 452; Michel, P., et al. (2018), AdSpR, 62, 2261.
Estimating detectability of phosphine in the Venusian atmosphere using spectral modeling
Authors: Deopersad Varuna
Published: July 2024

This study aims to determine if phosphine is detectable in the atmosphere of Venus and at what spectral wavelengths this may be possible. Phosphine is considered a biosignature, and its presence may imply the existence of life on Venus. The quantity of phosphine present in the atmosphere of Venus is a controversial subject and has been investigated using various in situ and Earth-based measuring devices. Due to disagreement in past research concerning detected concentrations of phosphine, further research into the possible detectability of phosphine on Venus is warranted. In this project, version 19 of the PHOENIX spectra modeling software is used to create synthetic spectra of the Venusian atmosphere. Physical parameters (temperature stratification, pressure stratification, atomic lines, molecular lines, continuum cross-section and irradiation) of the Venusian atmosphere and its environment are input into the model. The concentration of phosphine is manipulated and the synthetic spectral output produced is observed. In a synthetic atmosphere with 20 ppb of phosphine the chemical can be detected at ~1.123x107 Å(~266.94 GHz), which agrees with empirical telescopic observations. Phosphine may also be detected at ~1.134x107 Å (~264.35 GHz) and ~ 1.367x107 Å (~219.25 GHz). The latter will potentially provide the strongest signal and can be investigated further by telescopes assuming that there are not many sources of noise at this wavelength.
Magnetic Topology at Mars and Venus
Authors: Xu Shaosui
Published: July 2024

The Venus and Mars interactions with the solar wind are often compared because both planets lack a substantial intrinsic global magnetic field, and both have CO2-dominated atmospheres thick enough to form an ionosphere (ionized atmospheric layer). To first order, their magnetospheres are mainly induced in nature, with draped interplanetary magnetic fields (IMF) dominating their topology. However, this simple picture can be complicated by the magnetization of the ionosphere at Venus and Mars’s localized crustal field magnetism. An important property of these planet-solar wind interactions is the magnetic field’s connectivity to the collisional ionosphere/atmosphere, and possibly the planet surface. This can provide insights into the induced magnetization state of their ionospheres, the possible particle and energy exchange between their ionospheres and the solar wind, and the impact Mars’s crustal fields have on its near-space environment. Suprathermal (>1 eV) electrons are easily magnetized and excellent tracers of magnetic topology. In this talk, we describe the use of combined electron energy and pitch angle distributions measured by Venus Express and Mars Atmospheric Volatile and EvolutioN (MAVEN) to infer magnetic topology at Venus and Mars, respectively. We will review the main contributions of magnetic topology to the understanding of the Mars and Venus plasma environment. 
The small size and high geometric albedo of the Haumea cluster member 1995 SM55 from a stellar occultation and ground based photometry
Authors: Ortiz Jose L. , Morales Nicolas , Sicardy Bruno , Fernandez-Valenzuela Estela , Braga-Ribas Felipe , Rizos Juan Luis , Kretlow Mike , Gómez-Limón José María , Kilic Yucel , Erece Orhan , Akoz Ibrahim , Uluc Kadir , Kaspi Shai , Marciniak Anna , Turcu Vlad , Moldovan Dan , Sonka Adrian , Petrescu Elisabeta , Nedelcu Alin , Nehir Caglayan ,   Lucky Star collaborators and Observers of the 1995SM55 occultation campaing in 2024
Published: July 2024

The Trans-Neptunian Object with provisional designation 1995SM55 is one of the few members of the Haumea orbital cluster and therefore it is a very relevant body to study through the occultation technique in order to accurately determine size, shape and geometric albedo.  A very wide campaign involving 50 telescopes was arranged to observe a stellar occultation by this body on 25 February 2024, given that an astrometric update soon before the occultation indicated a good chance of detecting the event. Taking into account that the involved star was relatively bright, at G=12.4 mag, accessible to numerous instruments, the probability of success was high. In the end 7 positive detections from 5 different observatories were obtained and 33 sites obtained negative results. From a preliminary analysis of the occultation results together with ground based photometry data on 1995SM55 that we have gathered over more than a decade with various telescopes, we have been able to determine an accurate projected size and geometric albedo for this object. It turns out that the body is remarkably small for its brightness and therefore it has a high geometric albedo. Given the orbital and spectral similarities of 1995SM55 with Haumea, a high albedo, comparable to that of Haumea and a small size was expected. The final geometric albedo turned out to be even higher than that of Haumea.
From dust to planets: the ALMA and VLA view of planet formation
Authors: Zagaria Francesco
Published: July 2024

Over the last decade, the Atacama Large Millimeter/submillimeter Array (ALMA) made it possible to observe protoplanetary discs, the birth sites of planets, at unprecedented angular resolution and sensitivity, revolutionising our understanding of planet formation. When observed at high-enough angular resolution, protoplanetary discs show sequences of axisymmetric dark and bright substructures, colloquially referred to as “gaps and rings”. The origin of such substructures and the role that they play in the planet formation process are, however, still debated. Substructures are considered to be either the signposts of ongoing interactions between (proto-)planets and their hosting discs, or the ideal location for the formation of new planetary bodies. The best way to solve this “chicken and the egg” problem is characterising the physical properties of these gaps and rings. In this talk, I will first discuss recent attempts to observationally infer the size, density, and temperature of dust in these rings, relying on collecting and modelling multi-frequency, i.e. (sub-)mm to cm, continuum observations in a handful of well studied systems. In particular, I will focus on CI Tau, the only T Tauri star where a candidate hot Jupiter was detected using radial velocity techniques. My high-angular resolution and sensitivity ALMA and VLA continuum observations of this source, reveal that the dust density and size locally increase at the position of the bright rings, suggesting that dust trapping is taking place. I will also show how CI Tau's unique spectral energy distribution allows putting unprecedented constraints on dust composition in this system. Finally, I will introduce a new technique that combines these dust properties with gas kinematics to understand if bright rings might be prone to the formation of planetesimals under streaming instability (SI). In the case of HD 163296, the only source where dust properties and gas kinematics have been well constrained so far, my method reveals that the outermost (100 au) ring shows favourable conditions to trigger the SI.
Characterizing rocky exoplanets without atmospheres
Authors: Koll Daniel D. B. , Lyu Xintong
Published: July 2024

Recent observations of the super-Earths LHS 3844b, GJ 1252b, and TRAPPIST-1b suggest many short-period rocky exoplanets do not have an atmosphere, and instead resemble bare rocks like the Moon or Mercury. These planets offer a unique opportunity to study exoplanet surface geology and probe how exoplanet surfaces are shaped by interaction with a planet’s orbital evolution, tidal heating, and other dynamics. Here we focus on two processes, tidal heating and space weathering, and simulate their impact on exoplanet observations with a new bare rock model. We show that the observed lack of large tidal heating on LHS 3844b requires that the planet must be tidally locked and its orbital eccentricity has to be less than $\sim0.001$ (more circular than Io’s orbit), thereby giving first support to tidal evolution models for small exoplanets. Turning to space weathering, we find that LHS 3844b’s thermal emission is hotter than expected for a fresh basaltic surface, but is matched well by a surface that was darkened by space weathering, indicating that space weathering is likely a widespread process on short-period bare rock exoplanets. Our results underline that bare rock exoplanets provide a unique opportunity to study exo-geology, test tidal evolution models, and probe planetary surface processes in a novel regime.
Radar Tomography of Asteroid Deep Interior - JuRa / HERA to Didymos and Ra proposed to APOPHIS
Authors: Herique Alain , Plettemeier Dirk , Kofman Wlodek
Published: July 2024

Alain Herique, Dirk Plettemeier, Wlodek Kofman, the JuRa Team, the droid team and the Ramses team  Our knowledge of the internal structure of asteroids relies entirely on inferences from remote sensing observations of the surface and theoretical modeling. Is the body a monolithic piece of rock or a rubble-pile, and how high is the porosity? What is the typical size distribution of the constituent blocks? Are these blocks homogeneous or heterogeneous? Direct measurements of an asteroid’s deep interior structure are needed to better understand asteroid accretion and their dynamic evolution. The characterization of the asteroids’ internal structure is crucial for science, planetary defense and exploration.In orbit Radars sounding are the most mature instruments capable of achieving the objective of characterizing the internal structure and heterogeneity, for the benefit of science as well as for planetary defense or exploration.This is the goal of JuRa, the Juventas radar, onboard the ESA HERA mission. JuRa is a monostatic radar, BPSK coded at 60MHz carrier frequency and 20MHz bandwidth, inherited from CONSERT/Rosetta. The instrument design is under integration on Juventas cubesat for the ESA HERA mission. HERA will be launched this autumn to deeply investigate the Didymos binary system and especially its moonlet Dimorphos, five years after the DART/NASA impact.The main objective of JuRA is to characterize the asteroid interior, to identify internal geological structure such as layers, voids and sub-aggregates, to bring out the aggregate structure and to characterize its constituent blocks in terms of size distribution from submetric to global scale. The second objective is to estimate the average permittivity and to monitor its spatial variation in order to retrieve information on its composition and porosity.The Radar to Apophis, RA, is a modified version of JuRa able to operate in both monostatic and bistatic modes between orbiting or landed CubeSats. This radar is proposed to probe Asteroid 99942 Apophis in 2029, a potentially dangerous asteroid which will then approach Earth as close as 32000 kilometers on the DROID JPL/CNES and the RAMSES ESA proposed mission. Knowledge of Apophis’ internal structure is crucial to better understand its accretion and dynamical evolution, to improve our ability to study its stability conditions and to model its response to the gravitational constraints induced by Earth close approach. The Multipass processing will allow us to build a 3D tomographic image of the interior at different scales from submeter to global.In this presentation we will show the instrument, its status, performances and goals as well as the science objectives in the context of the different targets.
Modeling the formation of carbonaceous chondrite parent bodies
Authors: Gurrutxaga Nerea , Drazkowska Joanna , Kleine Thorsten
Published: July 2024

Carbonaceous chondrites are some of the most primitive meteorites in our Solar System. They contain refractory inclusions, chondrules, and CI chondrite-like matrix, and originate from planetesimals accreted a few Myr after Solar System formation started. Recent work by Hellmann et al. (2023) showed that there is a fundamental link between the abundances of chondrules and Calcium-Aluminum-rich Inclusions (CAIs), highlighting their abundance is correlated in carbonaceous chondrites. Furthermore, their findings suggest a direct correlation between the abundance of fine-grained dust (i.e., matrix) within carbonaceous chondrites and the accretion time of their parent bodies. They proposed that variations in these abundances reflect the entrapment of CAIs and chondrule precursors within pressure maxima in the protoplanetary disk, likely associated with the gap opened during the formation of Jupiter.Motivated by these findings, we employ Monte Carlo simulations of dust evolution to explore the plausibility of carbonaceous chondrite parent body formation in the outer regions of a Jupiter-induced gap. Our investigation includes various collision models between refractory inclusions, chondrules and matrix-like materials. At high gas densities, small dust is well-coupled to the gas and can cross the gap, softening the barrier between outer and inner Solar System materials. However, we show that less fragmentation-prone refractory inclusions and chondrules may not leak through the gap. Therefore, their abundance increases in the outer regions (see Figure 1, left panel). As the gas disperses over time, small dust decouples from the gas and gets trapped outside the gap, reducing the previous enrichment of refractory inclusions and chondrules (see Figure 1, right panel). Under favourable conditions for triggering streaming instability, it is possible to reproduce the formation of carbonaceous chondrite parent bodies rich in refractory inclusions and chondrules while their abundance decreases over time.This scenario constrains current models of Solar System formation, as well as the intricate interactions between different constituents of carbonaceous chondrites and their incorporation into planetesimals. Furthermore, our results could provide valuable benchmarks for future laboratory experiments to elucidate how different materials can stick or fragment during collisions in protoplanetary disks. Figure 1: Gap-opening by Jupiter at different stages. Blue and black dots indicate matrix-like material and refractory inclusions or chondrules, respectively. Left: at the early stages of the gap-opening, small fragments of matrix-like material leak through the gap, enriching the abundances of refractory inclusions and chondrules in the outer regions of the gap. Right: at later stages, gas density decreases, and matrix loss is reduced. Consequently, the abundance of matrix-like material increases outside the gap.  