bluuebunny/crossref_metadata_2025 huggingface dataset:
Asteroid taxonomy using neural networks
Authors: Penttilä Antti , Hietala Hilppa , Muinonen Karri
Published: July 2021

We explore the performance of neural networks in automatically classifying asteroids into their taxonomic spectral classes. We particularly focus on what the methodology could offer the ESA Gaia mission. We constructed an asteroid dataset that can be limited to simulating Gaia samples. The samples were fed into a custom-designed neural network that learns how to predict the samples’ spectral classes and produces the success rate of the predictions. The performance of the neural network is also evaluated using three real preliminary Gaia asteroid spectra.The overall results show that the neural network can identify taxonomic classes of asteroids in a robust manner. The success in classification is evaluated for spectra from the nominal 0.45–2.45 µm wavelength range used in the Bus-DeMeo taxonomy, and from a limited range of 0.45–1.05 µm following the joint wavelength range of Gaia observations and the Bus-DeMeo taxonomic system. The obtained results indicate that using neural networks to execute automated classification is an appealing solution for maintaining asteroid taxonomies, especially as the size of the available datasets grows larger with missions like Gaia.
The interior-atmosphere coupling of rocky worlds
Authors: Adhiambo Vivian , Root Bart , Desert Jean-Michel
Published: July 2021

Earth has been the only known habitable world and thus used as a reference to understand habitability. The origin of life on Earth is not yet clearly understood, but known traces are up-to the Archean (∼ 3.5Ga, Ga-billion years). Earth had water and continents from the Hadean Earth (> 4.0Ga), which had different atmospheric conditions compared to the Archean Earth. Similarly, the current state and composition of atmosphere does not represent its future state. Climate changes are partly attributed to feedback mechanism between the internal processes and the atmosphere. And as such, each atmospheric state is depictive of an instance a long a trajectory path of a coupled evolution of Earth system. Venus was thought to be habitable until into the 1960s, when its surface was observed to be oven-hot with surface pressure a hundred times that of Earth. Why and when the evolutionary paths of Venus and Earth, which are similarly sized and should have similar internal compositions, started to diverge? Moreover, known exoplanets, planets and moons have very different geophysical characteristic from Earth. This implies exotic life might vary substantially from what we know. As a result, understanding evolution of rocky planets, that is their interior structure, atmospheres and climate regardless of their habitability is of great importance. In this work we study the relation between a rocky planet’s internal properties and its observable surface and atmosphere properties over time.   We explore the different convection regimes (stagnant lid, episodic-lid and tectonic), studying the relation between a planet’s viscous state, its interior composition and structure. Focusing on the effects of mantle convection on volatile recycling processes such as CO2 outgassing that influence the atmospheric state and climatic conditions over time. The computed models are then used to compute observables, that ultimately can be tested with observations.
The cometary matter between volatiles and macromolecules
Authors: Hänni Nora , Altwegg Kathrin , Müller Daniel , Pestoni Boris , Rubin Martin , Wampfler Susanne
Published: July 2021

Small and volatile molecules are the most abundant constituents of a comet’s neutral coma. Thanks to ESA’s Rosetta mission, the neutral coma of comet 67P/Churyumov-Gerasimenko (67P hereafter) has been analyzed in great spatial and temporal detail, e.g., by Rubin et al. (2019) or by Läuter et al. (2020). However, the Double Focusing Mass Spectrometer (DFMS) – part of the Rosetta Orbiter Spectrometer for Ion and Neutral Analysis (ROSINA; Balsiger et al. 2007) – delivered data which contains information about the transition region between volatiles and macromolecular matter. Manual fitting of individual spectra allows to resolve pure hydrocarbon from heteroatom-bearing species also in the higher mass-range of the instrument, up to mass-to-charge (m/z) ratios of 140.While Altwegg et al. (2019) have reported tentative detections of some heavier species like benzoic acid or naphthalene, spectra of m/z>70 have not been investigated systematically. Here, we will present preliminary results from the first comprehensive analysis of a full data set (from m/z=12 to m/z=140) collected on August 3, 2015. On this day, the comet was close to its perihelion and the dust activity, as seen by the OSIRIS camera (Vincent et al. 2016), was high. Probably due to sublimation of molecules from ejected and heated-up dust grains, ROSINA/DFMS registered many signals above m/z=70. Due to the problem of isomerism and the lack of reference data, we chose to follow a statistical approach for our analysis. Larger species tend to expose a lower degree of saturation and the H/C ratio seems to approach that of highly unsaturated insoluble organic matter (IOM), cf., e.g., Sandford 2008. Although we cannot identify individual molecules in the complex gas mixture that makes up for the cometary coma, we are able to characterize for the first time the larger organic species that bridge the small volatiles and the macromolecular matter observed in 67P’s dust by the Rosetta secondary ion mass spectrometer COSIMA (Fray et al. 2016).   Altwegg et al., 2019, Annu. Rev. Astron. Astrophys., 57, 113-55.Balsiger H. et al., 2007, Space Sci. Rev., 128, 745-801.Fray et al., 2016, Nature, 538, 72-74.Läuter et al., 2020, MNRAS, 498, 3, 3995-4004.Rubin et al., 2019, MNRAS, 489, 594-607.Sandford, 2008, Annu. Rev. Anal. Chem. 1, 549–78.Vincent et al., 2016, MNRAS, 462 (Suppl_1), 184-194.
The impact of time-dependent stellar activity on the atmospheric chemistry and observability of exoplanets
Authors: Louca Amy , Miguel Yamila , Tsai Shang-Min
Published: July 2021

Observations of exoplanets used to characterize the chemistry and dynamics of atmospheres have developed considerably throughout the years. Nonetheless, it remains a difficult task to give a full and detailed description using solely observations. With future space missions such as JWST and ARIEL, both expected to be launched within this decade, it becomes even more crucial to be able to fully explain and predict the underlying chemistry and physics involved. In this research, we focus on modeling star-planet interactions by using synthetic flare spectra to predict chemical tracers for future missions. We make use of a chemical kinetics code that includes synthetic time-dependent stellar spectra and thermal atmospheric escape to simulate the atmospheres of known exoplanets. Using a radiative transfer model we then retrieve emission spectra. This ongoing study is focused on various known planetary systems of which the stellar spectrum has been obtained by the (mega-)MUSCLES collaboration. Preliminary results on these systems show that stellar flares and thermal escape can have a significant effect on the chemistry in atmospheres. 
Modeling volatile species in magma ocean-atmosphere interactions on hot rockyexoplanets
Authors: Van Buchem Christiaan , Miguel Yamila , Van Westrenen Wim
Published: July 2021

Hot rocky exoplanets present us with the unique opportunity to give us insights into their interiors through the characterization of their atmospheres. With the upcoming launch of the JWST and ARIEL ushering in a new era of exoplanet observations, this topic is becoming more relevant than ever. A crucial element in this work is the accurate modeling of the interaction between planetary atmospheres and their magma oceans. The key question here being: What is the atmospheric composition of a hot rocky exoplanet for a given magma ocean composition? One pressing issue one must face when answering this question is the inclusion of volatile species (such as H2, H2O, CO2, etc.). Currently, hot rocky exoplanets are often assumed to be entirely depleted of volatile species, or simplified models are applied in which but a few species in both the melt and the atmosphere are taken into account.In this presentation we will show our ongoing work on including volatiles species in the modeling of magma ocean-atmosphere interactions on hot rocky exoplanets. The successful development of this method and subsequent comparisons to observations would allow us to start characterising rocky exoplanet compositions which could lead to new insights for formation models. Furthermore, it would also allow us to model the effects of transient magma oceans though to be present on young earth analogs. Deepening our understanding of how such processes influence the conditions present during later evolutionary stages could give us new insights in the evolution of the earth and the conditions necessary to sustain life.
A global model of meteoric metals in the atmosphere of Mars
Authors: Feng Wuhu , Plane John , González-Galindo Francisco , Marsh Daniel , Welch Adam , Carrillo-Sánchez Juan Diego , Janches Diego , Chaufray Jean-Yves , Forget Francois , Millour Ehouarn , Crismani Matteo , Schneider Nicholas , Benna Mehdi
Published: July 2021

Here we report a global model of meteoric metals including Mg, Fe and Na in the Laboratoire de Météorologie Dynamique (LMD) Mars global circulation model (termed as LMD-Mars-Metals), following on similar work as we have done for the Earth’s atmosphere. The model has been developed by combining three components: the state-of-the-art LMD-Mars model covering the whole atmosphere from the surface to the upper thermosphere (up to ~ 2 x10-8 Pa or 240 km), a description of the neutral and ion-molecule chemistry of Mg, Fe and Na in the Martian atmosphere (where the high CO2 abundance produces a rather different chemistry from the terrestrial atmosphere), and a treatment of injection of the metals into the atmosphere as a result of the ablation of cosmic dust particles. The LMD-Mars model contains a detailed treatment of atmospheric physics, dynamics and chemistry from the lower atmosphere to the ionosphere. The model also includes molecular diffusion and considers the chemistry of the C, O, H and N families and major photochemical ion species in the upper atmosphere, as well as improved treatments of the day-to-day variability of the UV solar flux and 15 mm CO2 cooling under non-local thermodynamic equilibrium conditions. So far, we have incorporated the chemistries of Mg, Fe and Na into LMD-Mars because these metals have different chemistries which control the characteristic features of their ionized and neutral layers in the Martian atmosphere. The Mg chemistry has 4 neutral and 6 ionized Mg-containing species, connected by 25 neutral and ion-molecule reactions. The corresponding Fe chemistry has 39 reactions with 14 Fe-containing species. Na chemistry has 7 neutral and only 2 ionized Na-containing species, with 32 reactions. The injection rate of these metals as a function of height is pre-calculated from the Leeds Chemical Ablation Model (CABMOD) combined with an astronomical model which predicts the dust from Jupiter Family and Long Period comets, as well as the asteroid belt, in the inner solar system. The LMD-Mars-Metals model has been run for several full Martian years under different surface dust scenarios to investigate the impact of high atmospheric dust loadings on the modelled metal layers. The model has been evaluated against Mg+ observations from IUVS (Imaging UV Spectrometer) and NGIMS (Neutral Gas Ion Mass Spectrometer) instruments on NASA’s Mars Atmosphere and Volatile Evolution Mission (MAVEN) spacecraft. We have also carried out other sensitivity experiments with different seasonality/altitude/latitudinal varying of Meteoric Input Function (MIF) of these metals in the model. These sensitivity results will be discussed.  
Selfgravitating vortices in protoplanetary disks
Authors: Rendon Restrepo Steven , Barge Pierre
Published: July 2021

    Large scale vortices are thought to be natural outcomes of hydrodynamic instabilities in protoplanetary disks, as for instance the Rossby Wave Instability [1] or Baroclinic instability. Analytical and numerical studies showed that they can be long-lived and catalyze efficiently dust material concentration (e.g) [2], [3] and encourage to think they could play a role in protoplanetary-disk evolution and planetesimal formation. Their presence in the outer regions of circumstellar disks is possibly betrayed by recent observations of lopsided structures with ALMA and VLT [4], [5] and raises also a question: what is the importance of disk self-gravity on their structure and evolution.    We present 2D hydrodynamical simulations of steady vortices evolving under the effect of their own gravity. The goal is to study their evolution and the possibility of gravitational collapse. Are particularly addressed the structure, migration, mass, and physical variables characterizing these self-gravitating structures. We also pay special attention to the case of very massive vortices.Figure 1. From left to right: Rossby number and density (in log scale) perturbations induced by a large scale vortex after 171 orbital periods at 7.5 AU.[1] Lovelace, R. V. E., Li, H., Colgate, S. A., & Nelson, A. F. 1999, ApJ, 513, 805[2] Barge, P. & Sommeria, J. 1995, A&A, 295, L1[3] Raettig N, Klahr H Lyra W, 2015, ApJ804[4] Tsukagoshi, T., Muto, T., Nomura, H., et al. 2019, ApJ, 878, L8[5] Dong, R., Liu, S.-y., Eisner, J., et al. 2018, ApJ, 860, 124
Probing the Jupiter-Io interaction with synergistic measurements of radio and ultraviolet auroral emissions from Juno, Nançay and HST observatories
Authors: Lamy Laurent , Colomban Lucas , Zarka Philippe
Published: July 2021

The prominent component of Jovian decametric (auroral) emissions is induced by Io. Io decametric emissions (Io-DAM) have thus been monitored on a regular basis by Earth- or Space-based radio observatories for several decades. They display a typical arc-shaped structure in the time-frequency plane which results from the motion of the Io flux tube relative to the observer convolved with the anisotropic radio emission cone. Remote determination of the Io-DAM beaming pattern was used to check the emission conditions at the source (e.g. Queinnec & Zarka, 1998). It has been done at several occasions using various models of magnetic field/lead angles which introduce significant uncertainties. Nevertheless, Io-DAM arcs were shown to be consistent with oblique emissions triggered by the Cyclotron maser Instability from loss-cone electron distributions of a few keVs (Hess et al., 2008). The CMI validity for Jovian DAM and the prominence of loss cone electron distributions has been later confirmed by Juno in situ measurements (e.g. Louarn et al, 2017). In this study, we took advantage of simultaneous radio/UV or bi-point stereoscopic radio measurements provided by Juno/Waves, the Nançay Decameter Array and the Hubble Space Telescope to unambiguously derive the beaming pattern of several Io-DAM arcs and compare it with theoretical expectations. We then assess the energy of CMI-unstable auroral electrons at the source and discuss our results at the light of similar independent studies reaching different conclusions.
Towards detecting carbon chemistry on planetary objects with the ORIGIN space instrument
Authors: Kipfer Kristina , Ligterink Niels , Schwander Loraine , de Koning Coenraad , Keresztes Schmidt Peter , Grimaudo Valentine , Lukmanov Rustam , Tulej Marek , Bouwman Jordy , Riedo Andreas , Wurz Peter
Published: July 2021

Polycyclic aromatic hydrocarbons (PAHs) are thought to play an important role as indicators for chemical processes in the interiors and on the surfaces of planets and moons. Based on the strength of the Unidentified Infrared Bands it is estimated that 10 –25% of all carbon in the ISM joins together to form the multi-ringed structure of PAHs [Tielens, 2008]. Therefore, this class of molecules is a ubiquitous and important tracer of chemical processes, which can be investigated with instruments on space exploration missions.The ORganics Information Gathering INstrument (ORIGIN) is a prototype space instrument developed and built at the University of Bern, Switzerland, for the detection of biomolecules on planetary surfaces [Ligterink et al., 2020] [Riedo et al., 2013]. ORIGIN is Laser Ionization Mass Spectrometer (LIMS) operated at desorption conditions. A single 266 nm nanosecond laser pulse is used to desorb and ionize gently molecules from a steel sample surface, located in a vacuum chamber at a pressure of P
Thermal conductivity measurements of frozen salt solutions in Jovian moons to support future JUICE mission.
Authors: González Díaz Cristóbal , Muñoz Caro Guillermo M. , Carrascosa de Lucas Héctor , Aparicio Secanellas Sofía , González Hernández Margarita , Anaya Velayos José J. , Anaya Catalán Guillermo , Prieto-Ballesteros Olga , Muñoz-Iglesias Victoria , Ercilla Herrero Oscar , Lorente Rosario , Altobelli Nicolas , Witasse Olivier
Published: July 2021

The upcoming JUpiter ICy moons Explorer (JUICE) (ESA) and Europa Clipper (NASA) missions will perform detailed observations of the giant gaseous planet Jupiter and three of its largest moons (Ganymede, Callisto, and Europa).A series of experiments was performed to measure the thermal conductivity and calorimetry of macroscopic frozen salt solutions of particular interest in Jovian icy moons. The following salts were investigated: Na-chloride (NaCl), Mg-sulphate (MgSO4), sodium sulphate (Na2SO4), and Magnesium chloride (MgCl2). Measurements were performed at atmospheric pressure and temperatures from 0 to -70ºC in a climatic chamber. Temperature and thermal conductivity were measured during the course of the experiments. A small sample of the liquid salt-water solution was set aside for the calorimetry measurements. A side effect of the measurements is that they served to spot phase changes in the ice mixtures with high sensitivity. An important result is that, the phase changes observed in the standard calorimetric tests, could be monitored in situ with high sensitivity in the thermal conductivity measurements. Indeed, when a phase change occurs, a large peak appeared in the thermal conductivity values as the result of the natural heat release that accompanied the phase change. 
Terrestrial planet accretion constrained by isotopes: Implications for Earth-like habitats
Authors: Lammer Helmut , Scherf Manuel , Erkaev Nikolai V.
Published: July 2021

Here we discuss terrestrial planet formation by using Earth and our knowledge from various isotope data such as 182Hf-182W, U-Pb, lithophile-siderophile elements, atmospheric 36Ar/38Ar, 20Ne/22Ne, 36Ar/22Ne isotope ratios, the expected solar 3He abundance in Earth’s deep mantle and Earth’s D/H sea water ratios as an example. By analyzing the available isotopic data one finds that, the bulk of Earth’s mass most likely accreted within 10 to 30 million years after the formation of the solar system. Proto-Earth most likely accreted a mass of 0.5 to 0.6 MEarth during the disk lifetime of 3 to 4.5 million years and the rest after the disk evaporated (see also Lammer et al. 2021; DOI: 10.1007/s11214-020-00778-4). We also show that particular accretion scenarios of involved planetary building blocks, large planetesimals and planetary embryos that lose also volatiles and moderate volatile rock-forming elements such as the radioactive decaying isotope 40K determine if a terrestrial planet in a habitable zone of a Sun-like star later evolves to an Earth-like habitat or not. Our findings indicate that one can expect a large diversity of exoplanets with the size and mass of Earth inside habitable zones of their host stars but only a tiny number may have formed to the right conditions that they could potentially evolve to an Earth-like habitat. Finally, we also discuss how future ground- and space-based telescopes that can characterize atmospheres of terrestrial exoplanets can be used to validate this hypothesis.   
Mapping exoplanet atmospheres in high energy environments
Authors: Louden Tom
Published: July 2021

Exoplanet atmospheres are often treated as a single monolithic whole in transmission spectroscopy, while in reality they are dynamic and complex objects rich with inhomogeneities. We will show that using the technique of transit limb scanning it is possible to recover additional information on the spatial, chemical and velocity distributions of planet atmospheres that would otherwise have been lost.We will present results of transit limb scanning applied to a variety of hot jupiters, in particular using high resolution data of the sodium absorption to recover the equatorial and polar wind speeds on several planets spanning the temperature regime, and a new model of the metastable helium outflow of WASP 107b, where we find strong evidence of an extended comet-like tail.In each case we fit a variety of models with different atmosphere architecture in increasing complexity to the time resolved high resolution transmission spectra, using a Bayesian evidence approach to model comparison in order to find the model that best explained the data.Mapping exoplanets will be the key to solving a number of theoretical issues, as atmospheric wind speed is governed by the level of drag in the atmosphere, which is not well constrained by theoretical models. Similarly, the shape of helium outflows on evaporating planets will be important to proper determinations of evaporation rate, which sculpts the shape of the entire planet population.
Geological modeling at ESA's ExoMars 2022 landing site Oxia Planum
Authors: Frigeri Alessandro , De Sanctis Maria Cristina , Ciarletti Valerie , Altieri Francesca , Ammannito Eleonora , Apuzzo Andrea , Brossier Jérémy , Ercoli Maurizio , Ferrari Marco , De Angelis Simone , Formisano Michelangelo , Fonte Sergio
Published: July 2021

The current generation of rovers exploring Mars for traces of life feature tools for subsurface sampling capabilities.  This addition to the sampling capabilities of the martian rovers is crucial for the search for life.  In fact, in the subsurface life is more likely to be protected from the harsh radiation environment present on the surface.  The sampling of subsurface materials started with the analysis of the first millimeters of unweathered rocks being pulverized or abraded (NASA/MSL), evolved with the extraction of small cores from the first 10 centimeters (NASA/Mars2020), and will continue with the exploratory drilling of ESA's ExoMars 2022 which is capable of reaching 2 meters of depth.  The proper planning and interpretation of measurements below the topographic surface require a model of the subsurface.  Geological models are digital representations of subsurface structures generated by the sequence in time of processes putting in place different rocks and terrains.  Geologic cross-sections are an example of bi-dimensional modeling that extends observations taken at the surface.  Modern geologic models are commonly developed in three dimensions and used for terrestrial resource exploration, seismic analyses, and hydrologic simulations.   The key to a good geologic model is the integration of measurements taken by different instruments.  For ExoMars 2022, observations at the surface will be extended at depth by the spectrometer Ma_MISS which will read the mineralogical composition down to two meters, and the radar WISDOM which will collect geophysical images of the terrain down to ten meters or more.   In this work, we explore different methods to generate geological models of the subsurface of areas at Oxia Planum and a selection of analog outcrops at different scales.
Thermal evolution and redistribution of trace elements inside the mantles of Earth and Mars
Authors: Schmidt Julia , Noack Lena
Published: July 2021

The thermal evolution of a planet is heavily dependent on the concentration of heat producing elements inside of its mantle. Since heat producing elements like 40K, 232Th, and 238U are incompatible in the solid mantle, melting processes trigger a redistribution of these elements from the solid towards the melt. Because the melt has a lower density than the surrounding material, it rises towards the surface and takes the incompatible trace elements with it. This causes the mantle to be depleted and the surface to be enriched with heat producing elements, which has a big impact on the overall thermal evolution of a terrestrial planet.With the help of partition coefficients, the redistribution of trace elements can be calculated. In the past, mantle evolution models relied on fixed experimental data to model the redistribution of trace elements, but since partition coefficients are heavily dependent on pressure, temperature, and composition (Fig. 1), calculating them for each P-T-X condition would generate much more exact results. Previous partitioning models from Blundy et al. (1995) [1] were able to parameterize a partitioning model up to approximately 4 GPa, but for mantle evolution models a partitioning model up to 12 GPa would be preferable. This is why, based on Blundy et al. (1995) [1], we created a new parameterization for sodium partitioning which is applicable between 4-12 GPa [2]. Based on Blundy et al. (2003) [3], we based a broader approach for trace element partitioning between clinopyroxene/melt on the sodium partitioning model. By inserting the partition coefficient calculations into a mantle evolution model (Fig. 2), it is now possible to trace the redistribution of heat producing elements based on pressure, temperature, and melt composition. With this, we are now able to model the thermal evolution (or more specifically the cooling) of the mantles and crust formation of Earth and Mars in much more detail than before. Fig. 1: The clinopyroxene/melt partition coefficient of Na parameterized to higher pressures. With increasing pressures, partition coefficients increase (see experimental data [4] (dots and shaded area). The model of Blundy et al. 1995 is applicable up to 4 GPa, while our model works best from 4 – 12 GPa (Schmidt and Noack, submitted). Fig. 2: Redistributed amount of the joint heat sources 40K, 232Th, and 238U on Mars after 600 Myrs. [1] Blundy, J.D., Falloon, T.J., Wood, B.J., and Dalton, J.A. (1995), J. Geophys. Res., 100, 15501-15515.[2] Schmidt, J., Lena, N. (2021), IARIA, (submitted)[3] Blundy, J.D. and Wood, B.J. (2003), RiMG, 52 (1), 59–123.[4] Chamorro, E., Brooker, R., Wartho, J.-A., Wood, B., Kelley, S., Blundy, J. (2002), Geochimica et Cosmochimica Acta, 66 (3), 507-519.
Extreme exoplanets as a tool to understand trends in exoplanets atmospheres.
Authors: Jacobs Bob , Désert Jean-Michel , Barat Saugata , Line Michael , Pino Lorenzo
Published: July 2021

The interpretation of general trends in exoplanet atmospheres is challenging because they exhibit a wide range of diverse properties in terms of composition, structure, and overall atmospheric physics. In this context exoplanet’s in extreme regimes can help to understand global planetary properties. In this project, we focus on a few exoplanets that are outliers in their atmospheric properties and discuss what we can learn about the overall population of hot-jupiters from these peculiar objects.  We present studies of exo-atmospheric processes in extreme regimes of temperature, of entropy, of radiative and advective timescales, and of formation stages. This project combines these various physical properties in a unique and innovative manner to understand the most crucial properties of hot-Jupiters. Practically, we leverage the unique capabilities of Hubble Space Telescope Wide Field Camera 3 together with novel data analysis techniques to understand the nature of a set of exoplanets that reside under these extreme conditions. Ultimately, this project enable us to improve our understanding of exo-atmospheric processes and planet formation that ultimately shape the atmospheres of hot Jupiters that are observed today. 
The HR-LR duality of exoplanet atmospheres
Authors: Morello Giuseppe
Published: July 2021

We try to reconcile contrasting results about the composition of exoplanet atmospheres investigated with high-resolution and low-resolution spectroscopy.
Magnetic Field Aligned Potentials as an Acceleration Mechanism at Jupiter
Authors: Constable Dave , Ray Licia , Badman Sarah , Arridge Chris , Lorch Chris , Gunell Herbert
Published: July 2021

Since arriving at Jupiter, Juno has observed instances of field-aligned proton and electron beams, in both the upward and downward current regions. These field-aligned beams are identified by inverted-V structures in plasma data, which indicate the presence of potential structures aligned with the magnetic field. The direction, magnitude and location of these potential structures is important, as it affects the characteristics of any resultant field-aligned current. At high latitudes, Juno has observed potentials of 100’s of kV occurring in both directions. Charged particles that are accelerated into Jupiter’s atmosphere and precipitate can excite aurora; likewise, particles accelerated away from the planet can contribute to the population of the magnetosphere.Using a time-varying 1-D spatial, 2-D velocity space Vlasov code, we examine magnetic field lines which extend from Jupiter into the middle magnetosphere. By applying and varying a potential difference at the ionosphere, we can gain insight into the effect these have on the plasma population, the potential structure, and plasma densities along the field line. Utilising a non-uniform mesh, additional resolution is applied in regions where particle acceleration occurs, allowing the spatial and temporal evolution of the plasma to be examined. Here, we present new results from our model, constrained, and compared with recent Juno observations, and examining both the upward and downward current regions.
ESA Terrae Novae Exploration Strategy 204
Authors: Vijendran Sanjay , Schlutz Juergen , Gerst Alexander , Istasse Eric , De Mey Stefaan , Schmitt Didier
Published: July 2021

ESA’s Exploration Programme, recently renamed “Terrae Novae”, encompasses all ESA’s human and robotic activities related to the exploration and utilisation of Earth Orbit, Moon and Mars.  Its vision is to expand Europe’s human presence into the solar system using robotic missions as precursors, with the horizon goal of human Mars exploration; and to do this for science, economic benefits, to promote global cooperation and for inspiration[1].  In autumn 2020, ESA initiated a two-year long project to define the Terrae Novae long-term strategy, looking to 2030 and beyond. This abstract provides an introduction to the objectives of the project and summarises the progress and results to date. It is the ultimate goal of the strategy work to provide a lighthouse, to enable a steady orientation and long-term navigation of Europe’s decision makers on their voyage beyond the current horizons. The strategy work does not revisit the fundamental goals of ESA’s exploration programme as stated above;  instead, it is preparing the next decisions in implementation that will have to be taken by ESA Member States at the at the ESA Council meeting at ministerial level in 2022 (CM22). Decisions will be required to maintain long term European capabilities (e.g. in Low Earth Orbit (LEO)) and to prepare the next steps (e.g. for lunar surface exploration and preparations to enable humans to Mars). ESA is already anticipating a significant increase in it's request for Exploration Programme funding at CM22. The Agenda 2025 of the new ESA Director General addresses challenges and objectives for ESA in the next four years, with an outlook to 2035[2]. Being ambitious is the keyword in this Agenda, in order to position a transformed ESA in an ever more world-wide competitive arena, by “making space for Europe”.In a fast evolving international context, the challenging task of the strategy project is to position Europe to realise its exploration ambition in two dimensions.The presentation will include a status on the strategy development work including the initial results that show options for an integrated exploration roadmap for Europe to 2040. Stakeholder consultation (Member States, Industry, Science Community etc) will continue throughout 2021 into 2022 with refinements of the strategy expected until finalisation and approval by ESA Member States around mid 2022.
[1]http://esamultimedia.esa.int/multimedia/publications/ESA_Space_Exploration_Strategy/offline/download.pdf

[2]Agenda 2025 of the ESA Director General (https://download.esa.int/docs/ESA_Agenda_2025_final.pdf)
 
 
 
The impact of different parameter sets on the classification of asteroid types
Authors: Klimczak Hanna , Kotłowski Wojciech , Oszkiewicz Dagmara , DeMeo Francesca , Kryszczyńska Agnieszka , Kwiatkowski Tomasz , Wilawer Emil
Published: July 2021

The aim of the project is the classification of asteroids according to the most commonly used asteroid taxonomy (Bus-Demeo et al. 2009) with the use of various machine learning methods like Logistic Regression, Naive Bayes, Support Vector Machines, Gradient Boosting and Multilayer Perceptrons. Different parameter sets are used for classification in order to compare the quality of prediction with limited amount of data, namely the difference in performance between using the 0.45mu to 2.45mu spectral range and multiple spectral features, as well as performing the Prinicpal Component Analysis to reduce the dimensions of the spectral data. This work has been supported by grant No. 2017/25/B/ST9/00740 from the National Science Centre, Poland.
Six transiting planets and a chain of Laplace resonances in TOI-178
Authors: Leleu Adrien
Published: July 2021

Determining the architecture of multi-planetary systems is one of the cornerstones of understanding planet formation and evolution. Resonant systems are especially important as the fragility of their orbital configuration ensures that no significant scattering or collisional event has taken place since the earliest formation phase when the parent protoplanetary disc was still present. As unveiled by TESS, CHEOPS, ESPRESSO, NGTS and SPECULOOS, TOI-178 harbours at least six planets in the super-Earth to mini-Neptune regimes, all planets but the innermost one form a 2:4:6:9:12 chain of Laplace resonances, and the planetary densities show important variations from planet to planet. TOI-178 have hence several characteristics that were not previously observed in a single system, making it a key system for the study of processes of formation and evolution of planetary systems. We will review what we know of TOI-178, and what we expect from futur observations.
Direct imaging and spectroscopy of exoplanets with the ELT/HARMONI high-contrast module
Authors: Houllé Mathis , Vigan Arthur , Carlotti Alexis , Choquet Élodie , Cantalloube Faustine , Phillips Mark W. , Sauvage Jean-François , Schwartz Noah , Otten Gilles P. P. L. , Baraffe Isabelle , Emsenhuber Alexandre , Mordasini Christoph
Published: July 2021

Combining high-contrast imaging with medium-resolution spectroscopy has recently been shown to significantly boost the direct detection of exoplanets. In this optic, HARMONI, one of the first-light instruments to be mounted on ESO's ELT, will be equipped with a single-conjugated adaptive optics system to reach the diffraction limit of the ELT in H and K bands, a high-contrast module dedicated to exoplanet imaging, and a medium-resolution (up to R = 17 000) optical and near-infrared integral field spectrograph. When combined, these systems will provide unprecedented contrast limits at separations between 50 and 400 mas. We will present in this talk the results of extensive simulations of exoplanet observations with the HARMONI high-contrast module. We used an end-to-end model of the instrument to simulate observations based on realistic observing scenarios and conditions. We then analyzed these observations with the so-called "molecule mapping" technique, which has shown in recent studies its efficiency to disentangle planetary companions from their host star and boost their signal. Although HARMONI has not been fully designed for high-contrast imaging, we will show that it should greatly outperform the current dedicated instruments, such as SPHERE on the VLT. We detect planets above 5σ in 2 hours at contrasts up to 16 mag and separations down to 75 mas in several spectral configurations of the instrument. Simulating planets from population synthesis models, we could image in this amount of time companions as close as 1 AU from a host star at 30 pc and as light as 2 MJup. We show that taking advantage of the combination of high-contrast imaging and medium-resolution spectroscopy through molecule mapping allows us to access much fainter planets (up to 2.5 mag) than the standard high-contrast imaging techniques. We also demonstrate that HARMONI should be available for near-critical exoplanet observations with this method during 60 to 70% of telescope time at the ELT.
Energetic Ion Precipitation in Jupiter’s Polar Auroral Region Observed by Juno/JEDI
Authors: Clark George , Paranicas Chris , Westlake Joseph , Mauk Barry , Kollmann Peter , Gladstone Randy , Greathouse Thomas , Dunn William
Published: July 2021

Remote observations clearly show that soft X-ray emissions at Jupiter concentrate poleward of the main oval forming a so-called “hot spot” (Gladstone et al., 2002; Dunn et al., 2016). One hypothesis proposes that the X-rays are likely produced from precipitating energetic heavy ions that become fully stripped via interactions in Jupiter’s upper atmosphere; however, the details regarding the ion source and acceleration mechanism(s) of the soft X-ray (~2 keV) component is still an active area of research. NASA’s Juno mission – a Jupiter polar orbiting spacecraft – is shedding light onto this mystery with in situ observations of the energetic particle environment over the poles, and coordinated observing campaigns with Earth-orbiting X-ray observatories, e.g., Chandra and XMM-Newton. Recent ideas supported by Juno data include: 1) pitch angle scattering of energetic ions via electromagnetic ion cyclotron waves in the outer magnetosphere (Yao et al., 2021); and 2) acceleration of ions to several MeV over Jupiter’s poles via field-aligned electric potentials (Clark et al., 2017; Haggerty et al., 2017; Clark et al., 2020; Yao et al., 2021). New techniques have been recently developed to push the capabilities of Juno’s Jupiter Energetic particle Detector Instrument (JEDI) to measure the > 10 MeV ions (Westlake et al., 2019; Kollmann et al., 2020). In this presentation, we utilize these techniques to characterize the precipitating fluxes of > 10 MeV ions over Jupiter’s polar region with the goal of better understanding the sources of Jupiter’s X-ray auroral emissions.
Forming a cold electron population at a weakly outgassing comet
Authors: Stephenson Peter , Galand Marina , Deca Jan , Henri Pierre , Carnielli Gianluca
Published: July 2021

The Rosetta Mission rendezvoused with comet 67P/Churyumov-Gerasimenko in August 2014 and escorted it for two years along its orbit. The Rosetta Plasma Consortium (RPC) was a suite of instruments, which observed the plasma environment at the spacecraft throughout the escort phase. The Mutual Impedance Probe (RPC/MIP; Wattieaux et al, 2020; Gilet et al., 2020) and Langmuir Probe (RPC/LAP; Engelhardt et al., 2018), both part of RPC, measured the presence of a cold electron population within the coma.Newly born electrons, generated by ionisation of the neutral gas, form a warm population within the coma at ~10eV. Ionisation is either through absorption of extreme ultraviolet photons or through collisions of energetic electrons with the neutral molecules. The cold electron population is formed by cooling the newly born, warm electrons via electron-neutral collisions. Assuming the radial outflow of electrons, the cold population was only expected at comet 67P close to perihelion, where outgassing rate from the nucleus was at its highest (Q > 1028 s-1). However, cold electrons were observed until the end of the Rosetta mission at 3.8au when the outgassing was weak (Q
Status of space science and planetary sciences in Uganda: Building it through synergies with Europe
Authors: Muheki Priscilla Muheki , Jurua Edward , Guenther Eike W. , Mutabazi Tom
Published: July 2021

Space Science and Astrophysics are currently emerging fields in most African countries and in particular Uganda. These two fields are known to be channels of socioeconomic development and as such need to be developed further in the different African countries. For this to be achieved, there is need to deal with the challenges in doing astronomy or space science research on the African continent for instance access to state of the art computational and observational facilities. Creating synergies between European and African countries offers a gateway to advancing astronomy in Africa. In East Africa, and in particular Uganda, Mbarara University of Science and Technology (MUST) is aiming at becoming a centre of excellence in Space Science and Astrophysics research. This has been possible through the funding from the Swedish International Development Agency through the International Science Programme at Uppsala University.I will briefly highlight the different projects going on at MUST in both Planetary and Space sciences. I will then focus on the results obtained in our study on “stellar activity as an important factor for planet habitability”. This study was carried out in collaboration with the Thueringer Landessternwarte-Tautenburg, Germany.
Overview of Zambia's drive for implementing space technology
Authors: Simpemba Prospery C. , Nyambuya Golden G. , Silungwe Denis , Namiluko Yaki
Published: July 2021

Zambia has been thriving on hired space technology for telecommunication, weather prediction, land and radar surveillance which has resulted into the country spending a lot of money for these technological services. This also compromises the reliability of the space technologies that are being used as the country has no full control over them. This concept note gives an overview of the recent space science activities in Zambia and the efforts being made in developing a guiding national space science policy. We highlight current research in space weather, ionospheric total electron content (TEC) measurements, remote sensing and meteorological predictions. These are linked also to the academic programmes being developed in the leading higher education institutions in the country.
Science Talks Africa: Towards a Dialectics of an African Science Space
Authors: Prosper Anuforoh , Mulindwa Tyra-Kaddu , Najmah Barlow , Kabiito Jonathan , Diyoke Augustine , Samuel Damilare , Nwogu Henry
Published: July 2021

In the last century, there has been a broadening in the scope of science in Africa; which, in turn, has seen a widespread adoption of new technologies by most African countries and causing an explosion in the number of local and international science actors. But that development, many have argued, has yet to translate into a commensurate improvement in the overall condition of life and living on the continent. And even less so on the science ecosystem — a fact that has been most tellingly revealed by the COVID-19 pandemic. This opens up critical questions on the nature of science and how it is communicated, especially in the context of the cultural and ideological differences, which exist between the Global North and Africa. Science Talks Africa as a science communication platform emerged mostly out of the need to engage science from that perspective, and also to address the need for both empirical and ideological spaces in which science actors moderate the dialectics of existing and emerging science and technology in the context of Africa.
Wing-wing Interaction - When Exoplanets interact with each other
Authors: Fischer Christian , Saur Joachim
Published: July 2021

Electromagnetic Star-Planet Interaction is a phenomenon that occurs when a planet is sufficiently close to its host star that Alfvén waves propagate to the star and can leave an imprint on the star. The resulting structure is called Alfvén wing. Stars also often have open field-line structures due to the influence of the stellar wind. In these open field line regions, two planets can share the same set of field lines at the same time. Therefore, it is possible that Alfvén wings interact with each other and cause a time-variability in the signal. We call this process wing-wing interaction. To understand wing-wing interaction further, we apply a three dimensional, fully time-dependent, magnetohydrodynamic model. There, we simulate two planets that generate star-planet interaction and eventually undergo wing-wing interaction. We present the temporal evolution of the Alfvén wings and of the Poynting flux. From these results, we can estimate how wing-wing interaction could appear in observations. 
Exploring the dust ring in the circum-binary disc around GG Tau A
Authors: Toci Claudia , Ceppi Simone , Cuello Nicolas , Lodato Giuseppe , Longarini Cristiano , Ragusa Enrico , Aly Hossam
Published: July 2021

Binaries and multiple systems are common among young stars (Reipurth et al. 2014). These stars are often surrounded by discs of gas and dust, formed due to the conservation of angular momentum of the collapsing cloud, thought to be the site of planet formation.In the case of binary systems, three discs can form: an outer disc surrounding all the stars (called circumbinary disc), and two inner discs around the stars. As circumbinary planets have recently been discovered by Kepler (see e.g., Martin 2018, Bonavita & Desidera 2020), it is crucial to understand the dynamics and evolution of circumbinary discs to better understand the initial conditions of planet formation in multiple systems.The GG Tau A system is an example of a young multiple T Tauri star. The binary is surrounded by a bright disc, observed in the continuum emission at different wavelengths (see e.g., Guilloteau et al. 1999; Dutrey et al. 2014; Phuong et al. 2020b) and in scattered light (e.g., Duchene et al. 2014, Keppler et al. 2020). The disc extends in the dust from 180 to 280 au from the center of mass, and in the gas up to 850 au. The inner (
How does volcanic outgassing differ on geological time scales between planets with and without plate tectonics?
Authors: Noack Lena
Published: July 2021

One of the main factors to assess the possible habitability of a rocky planet (either in or beyond our solar system) is its capability to maintain an atmosphere that allows for moderate temperatures at the surface and would allow water to occur in a liquid form, and that can help shield surface life from harmful radiation.The existence of an atmosphere depends on several factors - possible accretion from the nebula and catastrophic degassing from the crystallizing magma ocean during planet formation, later delivery of volatiles via comets, sinks of atmosphere gases to the surface or to space, and last, but definitely not least, volcanic release of volatiles from the mantle that where stored in the planet's interior during its formation stage.For planets of masses not too different from Earth, volcanic degassing plays a major role for the question if the planet could have an atmosphere. Lower-mass planets might not be able to keep an atmosphere but loose it entirely to space, and much more massive super-Earth planets will likely keep the primordial, catastrophically outgassed atmosphere during magma ocean crystallization, and may never be habitable at their surface due to a thick atmosphere rather comparable to Venus. The "Goldilocks zone" for potentially habitable rocky planets is therefore limited to a range from above Mars' mass to a few Earth masses. However, planets of a few Earth masses may not be able to efficiently outgas volcanic gases, if they are in a stagnant-lid regime. This may be different, though, for planets experiencing plate tectonics like Earth, where hot, molten material reaches the surface at plate boundaries and may therefore build up or replenish an atmosphere. The work presented here compares the efficiency of interior volatile depletion and degassing to the surface for rocky planets of different size and composition, either in the stagnant-lid or in the plate-tectonics regime.