bluuebunny/crossref_metadata_2025 huggingface dataset:
Low Water outgassing from (24) Themis and (65) Cybele – Implications on 3.1 µm water absorption spectra understanding
Authors: O'Rourke Laurence , Müller Thomas , Biver Nicolas , Bockelée-Morvan Dominique , Hasegawa Sunao , Valtchanov Ivan , Küppers Michael , Fornasier Sonia , Campins Humberto , Fujiwara Hideaki , Teyssier David , Lim Tanya
Published: October 2020

Asteroids (24) Themis and (65) Cybele have an absorption feature at 3.1 µm reported to be directly linked to surface water ice. We searched for water vapour escaping from these asteroids with the Herschel Space Observatory Heterodyne Instrument for the Far Infrared (HIFI). While no H2O line emission was detected, we obtain sensitive 3σ water production rate upper limits of Q(H2O) < 4.1 × 1026 mol. s−1 for Themis and Q(H2O) < 7.6 × 1026 mol. s−1 for Cybele. Using a Thermophysical Model (TPM), we merge data from Subaru/Comics and Herschel/SPIRE with the contents of a multi-observatory database to derive new radiometric properties for these two asteroids. For Themis, we find a thermal inertia Γ = 20+25-10 J m-2 s-1/2 K-1, a diameter 192 +10-7 km and a geometric V-band albedo pV = 0.07 ±0.01. For Cybele we obtain a thermal inertia Γ = 25 +28-19 J m-2 s-1/2 K-1, a diameter 282 ± 9 km, and an albedo pV = 0.042± 0.005. Using all inputs, we estimate that water ice intimately mixed with the asteroids’ dark surface material would cover < 0.0017% for Themis and < 0.0033% for Cybele of their surfaces, while an areal mixture with very clean ice (bond albedo 0.8 for Themis and 0.7 for Cybele) would cover < 2.2% for Themis and < 1.5% for Cybele, of their surfaces. While surface (& sub-surface) water ice may exist in small localized amounts on both asteroids, it is not the reason for the observed 3.1µm absorption feature.
Far-infrared flux densities of main belt asteroids from serendipitous Herschel/PACS observations
Authors: Szakáts Róbert , Kiss Csaba , Farkas-Takács Anikó , Marton Gábor , Müller Thomas , Pál András
Published: October 2020

The Herschel Space Observatory had two imaging instruments, working in the far-infrared and submillimetre regimes: the PACS cameras at 70/100 and 160 μm and the SPIRE photometers at 250, 350 and 500 μm. Small solar system bodies, especially main belt asteroids were serendipitously present in the field of view mainly in large scan maps. We identified these objects with the original aim to mark the affected sources in the Herschel PACS and SPIRE Point Source Catalogues. In our present study we extracted flux densities in the PACS bands for asteroids above the detection limit, either using  existing standard data products from the Herschel Science Archive, or re-reducing the PACS maps in the co-moving frame of the target. We obtained ~600 new flux density values for 270 asteroids, a significant increase in the number of Herschel asteroid observations. These new flux densities will be included in the Small Bodies: Near and Far (SBNAF) Infrared Database (Szakáts et al., 2020). The fluxes obtained from Herschel are excellent for radiometric studies to get the object's size, albedo and maybe also thermal properties, when combined with other measurements (Alí-Lagoa et al., 2020).
How a magnetic helix can develop at solstice in a Uranus-type rotating magnetosphere
Authors: Griton Léa , Pantellini Filippo
Published: October 2020

The characteristic relaxation time of the Uranus magnetosphere is of the order  of the planet's rotation period. This is also the case for Jupiter or Saturn. However, the specificity of Uranus (and to a lesser extent of  Neptune) is that the rotation axis and the magnetic dipole axis are separated by  a large angle (~60°) the consequence of which is the development of a highly dynamic and complex magnetospheric tail. In addition, and contrary to all other planets of the solar system, the rotation axis of Uranus happens to be quasi-parallel to the ecliptic plane which also implies a strong variability of the magnetospheric structure as a function of the season. The magnetosphere of Uranus is thus a particularly challenging case for global plasma simulations, even in the frame of MHD. We present a detailed analysis of MHD simulations of a fast-rotating magnetosphere inspired from Uranus at solstice. At first, a simplified case allows us to explain in detail the formation and the internal structure of a double helix that develops in the magnetotail at solstice. Then we analyse a "real" Uranus simulation with parameters for the solar wind and planetary magnetic field defined from the measurements of Voyager II flyby in 1986.
The variation of Venus cloud investigated from SOIR onboard Venus Express
Authors: Takagi Seiko
Published: October 2020

The Venus cloud consists of a main cloud deck at 47 – 70 km, with thinner hazes above and below. The upper haze on Venus lies above the main cloud surrounding the planet, ranging from the cloud top (70 km) up to as high as 90 km.The Solar Occultation in the InfraRed (SOIR) instrument onboard Venus Express (ESA) was designed to measure the Venusian atmospheric transmission at high altitudes (65 – 220 km) in the infrared wavelength range (2.2 – 4.3 µm) with a high spectral resolution. In Takagi et al. (2019), the optical properties of Venus’s haze layer above 90 km have been investigated using SOIR observations. Vertical and latitudinal profiles of the extinction coefficient, optical thickness, and mixing ratio of aerosols are retrieved.A new cloud model was constructed based on the results of Takagi et al. (2019). In this presentation, I will show the results of a radiative transfer calculation (in the near-infrared region) that incorporates a new cloud model and discuss themeteorological some changes that contribute to cloud variation. Furthermore, I will introduce Venus observation plan using the 1.6 m Pirka telescope and Multi-Spectral Imager (MSI) [Watanabe et al., 2012] mounted on the Cassegrain focus of the telescope at the Nayoro Observatory of Hokkaido University.
Equality of opportunities in geosciences: The EGU Awards Committee experience
Authors: Karatekin Özgür , Blunier Thomas
Published: October 2020

EGU, the European Geosciences Union, is Europe’s premier geosciences union, dedicated to the pursuit of excellence in the Earth, planetary, and space sciences for the benefit of humanity, worldwide. Every year, the EGU awards and medals programme recognises eminent scientists for their outstanding research contribution in the Earth, planetary and space sciences. In addition, it identifies the awardees as role models for the next generation of early career scientists to foster geoscience research.
Nominations for all the medals and awards are submitted every year online by 15 June by the members of the EGU scientific community. Any person can be nominated except the EGU president, vice-president council members (not including ex- officio members) and chair of the EGU committees. Then, each EGU medal or award is selected through a rigorous assessment of the candidates and their merits. The EGU Council, the medal and award committees’ members and the Union and division officers are committed to soliciting the nomination of deserving individuals by avoiding conflicts of interest. Proposal, selection of candidates and the time schedule are described in detail at EGU website.
It is a strict necessity when recognizing scientific excellence by any scientific association providing equal opportunities and ensuring balance. The processes and procedures that lead to the recognition of excellence has to be transparent and free of gender biases. However, establishment of clear and transparent evaluation criteria and performance metrics in order to provide equal opportunities to researchers across gender, continents and ethnic groups can be challenging since the definition of scientific excellence is often elusive.
This presentation aims to present the experience and the efforts of the European Geosciences Union to ensure equal opportunities, data and statistics will be presented in the attempt to provide constructive indications to get to the target of giving equal opportunities to researchers across gender, continents and ethnic groups.
Earth Bond albedo retrieval
Authors: Penttilä Antti , Uvarova Elizaveta , Vuori Mikko , Ihalainen Olli , Muinonen Karri
Published: October 2020

We are compiling a service, which will produce almost real-time estimates of the Earth Bond albedo in visual and near-infrared wavelengths using the multi-wavelength images from the NOAA Deep Space Climate Observatory’s (DSCOVR) Earth Polychromatic Imaging Camera (EPIC). The service will be based on the known land and sea surface types of the Earth and the angular distribution models (ADMs) from the Clouds and the Earth’s Radiant Energy System (CERES) project (some details in Ihalainen, M.Sc. thesis, 2019, University of Helsinki, Finland). Instead of applying the CERES ADM albedo estimates as such, we will only use the ADM shapes for different land and sea surface types, but scale them using the corresponding observations from the EPIC camera.As the EPIC camera will produce imaging of the Earth disk from the L1 point, in about every two hours and in 10 narrow band filters between 317–780 nm, we can follow the temporal changes in the Bond albedo both in short times scales and over longer periods. We will employ a custom-made classifier for cloud coverage over the Earth disk using the 10 bands in the EPIC images to improve the Bond albedo estimation with temporally suitable cloud coverage ADMs over the land or sea surface pixels.The service will be run automatically in a dedicated server, and will produce the Bond albedo estimates via a public web interface.Figure 1. An example image from EPIC camera, taken at Jan. 1st, 2019. The three first images, counting from the top left corner, are gray-scale images at wavelength bands 317 nm, 388 nm, and 780 nm. The fourth image is false-color RGB composite from those channels.Acknowledgements: Research supported by the Academy of Finland (project 298137).
GAUSS: Towards Sample Return from Dwarf Planet Ceres
Authors: Shi Xian ,   GAUSS Project Team
Published: October 2020

GAUSS (Genesis of Asteroids and EvolUtion of the Solar System) is a mission concept for the future exploration of Ceres. As both the largest resident of the main asteroid belt and the only dwarf planet in the inner Solar System, Ceres holds critical information for probing the evolution and habitability of our Solar System. NASA’s DAWN mission performed the by far most comprehensive investigation of Ceres during its over three year in-orbit operation around this unique world. Data collected by remote sensing instruments revealed an amazingly diverse landscape comprising different types of geological features. Beneath its volatile- and organic-rich surface, Ceres might have once possessed a global ocean, the remnants of which possibly still exist today as pockets of brine between the mantle and the crust. Hydrothermal activities that took place in recent geological time transferred materials deep inside Ceres to its surface, forming several outstanding surface features that are optimal for future sampling. Similar processes could occur on other ocean worlds in the Solar System, making Ceres a benchmark case for studying the evolution and habitability of these objects in general.To fully understand the physical and chemical evolution of Ceres, high resolution analyses of samples are necessary. With cryogenic sample return as its final step, the GAUSS project aims to answer the following key questions:What is the origin of Ceres and the origin and transfer of water and other volatiles in the inner solar system?
What are the physical properties and internal structure of Ceres? What do they tell us about the evolutionary and aqueous alteration history of icy dwarf planets?
What are the astrobiological implications of Ceres? Was it habitable in the past and is it still today?
What are the mineralogical connections between Ceres and our current collections of primitive meteorites?
Star And Planet’s Characterisation Through High Spectral Resolution
Authors: Maimone Maria Chiara , Chiavassa Andrea , Leconte Jeremy , Brogi Matteo
Published: October 2020

The study of exoplanets atmospheres is one of the most intriguing challenges in exoplanet field nowadays and the High Resolution Spectroscopy (HRS) has recently emerged as one of the leading methods for detecting atomic and molecular species in their atmospheres. In terms of numbers, if we define the resolution power R,  where λ is the wavelength and Δλ is the spectral resolution:     R= λ/Δλthen, “High Resolution Spectroscopy” means R > 50 000.Nevertheless extraordinary results have been achieved (Birkby, 2018), High Resolution Spectroscopy alone is not enough. 1D models of the host star have been coupled to HRS observations, but they do not reproduce the complexity of stellar convection mechanism (Chiavassa & Brogi, 2019). On the contrary,  3D Radiative Hydrodynamical simulations (3D RHS) take it into account intrinsically, allowing us to correctly reproduce asymmetric and blue-shifted spectral lines due to the granulation pattern of the stellar disk, which is a very important source of uncertainties at this resolution level (Chiavassa et al. 2017).However, numerical simulations have been computed independently for star and planet so far, while the acquired spectra are an entanglement of both the signals. In particular, some molecular species (e.g, CO) form in the same region of the spectrum, thus planetary and stellar spectral lines are completely mixed and overlapped. Therefore, a next step forward is needed: computing stellar and planetary models together.With our work, we aim at upgrading the already-in-place 3D radiative transfer code Optim3D (Chiavassa et al. 2009) —largely used for stellar purposes so far — to taking into account also the exoplanetary contribution. We propose to use simultaneously 3D RHS, performed for stars, and the innovative Global Climate Model (GCM), drawn up for exoplanets, in order to generate unprecedented precise synthetic spectra. As a springboard to test the code, we are carrying out the analysis of CO and H2O molecules on the well-know benchmark HD189733. Indeed, to disentangle those star’s and its companion’s signals due to the same molecules is one of the most challenging problems. In the end, we will be able to compute a complete dynamic characterisation: on one side, a precise knowledge of the stellar dynamic (i.e. convection-related surface structures) would allow to extract unequivocally the planetary signal; on the other one, a well-modelled dynamic of the planet (i.e. depth, shape, and position of spectral lines) would provide us with considerable information about the planetary atmospheric circulation.
The ExoMars Trace Gas Orbiter - First Martian Year in Orbit
Authors: Svedhem Håkan , Korablev Oleg , Mitrofanov Igor , Rodionov Daniel , Thomas Nicolas , Vandaele Ann Carine , Vago Jorge L. , Forget Francois , Wilson Colin
Published: October 2020

The Trace Gas Orbiter, TGO, concluded its first Martian year in orbit in March 2020. It has been a highly successful Martian year, starting with the rise, plateau and decay of the major Global Dust Storm in the summer of 2018. This has enabled interesting results to be derived on the dynamic behaviour as a consequence of the dust storm. One of the significant observations is a strong upward transport of water vapour that has been found during this time. Characterisations of the minor species and trace gasses are continuing and large numbers of profiles are being produced on a daily basis. A dedicated search of methane has shown that there is no methane above an altitude of a few km, with an upper limit established at about 20 pptv (2∙10-11).The solar occultation technique applied by the spectrometers has definitely proven its strength, both for its high sensitivity and for its capability of making high-resolution altitude profiles of several parameters in the atmosphere. Climatological studies, benefitting from the 400km, 74 degrees inclination non-solar synchronous orbit, have been initiated and will become more important now that a full year has passed, even if the full potential will be visible only after a few Martian years of operation. The FREND instrument has characterised the hydrogen in the shallow sub-surface on a global scale, at a spatial resolution much better than previous missions have been able to do. It has found areas at surprisingly low latitudes with significant amounts of sub-surface hydrogen, most likely in the form of water ice. The CaSSIS camera has made a high number of images over a large variety of targets, including the landing sites of the 2020 NASA and 2022 ESA rovers, Oxia Planum and the Jezero Crater. Stereo imaging has enabled topographic information and precise 3-D landscape synthesis.This presentation will summarise the highlights of the first Martian year and discuss planned activities for the near and medium term future.The ExoMars programme is a joint activity by the European Space Agency (ESA) and ROSCOSMOS, Russia. It consists of the ExoMars 2016 mission, launched 14 March 2016, with the Trace Gas Orbiter, TGO, and the Entry Descent and Landing Demonstrator, EDM, named Schiaparelli, and the ExoMars 2020 mission, to be launched in July/August 2020, carrying a Rover and a surface science platform to the surface of Mars.
A Fault on Mercury Revealed in 3-Dimensions
Authors: Pegg David L. , Rothery David. A. , Conway Susan. J. , Balme Matthew. R.
Published: October 2020

Mercury's tectonic history has been dominated by global contraction as the planet cools and shrinks. Previously, fault dips have been estimated by measuring offsets to the rims of craters displaced by fault movement. Here we present the first observations of a fault surface that has been exposed in three dimensions by a volcanic vent.Contractional tectonism is manifested through features such as lobate scarps, wrinkle ridges, and high relief ridges 1,2.  The stresses in Mercury's crust that generated this contractional tectonism have multiple possible origins. These include global contraction 3, tidal despinning 4, true polar wander 5, and mantle convection 6. A combination of factors probably generates many faults, but the dominant driver of contractional tectonics on Mercury is the global contraction of the planet 7. This shrinking may be up to 10 km radially. The estimates of the actual amount of reduction in global radius recorded by Mercury’s crust is 7.1 km if the average fault dip is 25o but as little as 4.7 km if the average fault dip is 35o11. An understanding of the dip of the faults on Mercury provides better input into these estimates and hence offers constraints on Mercury's thermal history.In the past, only indirect means were available to calculate dips of thrust faults, by using the shortening and vertical offset of craters that straddle faults 10,12. These studies derived an average dip of 25o. Until now, no-fault dip on Mercury has been measured by direct means.A crater located at 147.6oE, -65.6o N shows a small fault scarp that is visible on the side of a volcanic vent, and the trace is expressed also on the vent wall and floor. This is the first known fault surface on Mercury that is exposed in three dimensions.While a dip determination on a single fault is not conclusive, this result suggests that the shallower dip estimates are likely more representative estimates for average fault dips on Mercury and so adds weight to the higher end of the estimates of global contraction. Unfortunately, the resolution is insufficient for us to measure displacement by means of off-set features. BepiColombo will provide further opportunities to identify and measure similar features elsewhere on Mercury, and so help constrain the planet’s tectonic processes. References:  
Revisiting the atmosphere of HD 209458b with HARPS-N, CARMENES and ESPRESSO
Authors: Casasayas-Barris Núria , Palle Enric , Stangret Monika , Chen Guo , Yan Fei ,   ESPRESSO consortium
Published: October 2020

HD 209458b was the first transiting planet discovered, and the first for which its atmosphere, in particular Na I, was detected. With time, it has become one of the most studied planets, with a large diversity of atmospheric studies using low- and high-resolution spectroscopy. Here, we present the analysis of high-resolution transmission spectroscopy of HD 209458b using a total of five transit observations with HARPS-N and CARMENES spectrographs. In contrast to previous studies where atmospheric Na I absorption is detected, we find that, for all of the nights, either individually or combined, the transmission spectra can be explained by the combination of the centre-to-limb variation and the Rossiter-McLaughlin effect. Thus, the transmission spectrum reveals no detectable Na I absorption in HD 209458b. This is also observed in the time-evolution maps and transmission light curves, but at lower signal-to-noise ratio. Other strong lines such as Hα, Ca II IRT, the Mg I triplet region, and K I D1 are analysed, and are also consistent with the modelled effects, without considering any contribution from the exoplanet atmosphere. New ESPRESSO observations, with state-of-the-art stability and considerably larger signal-to-noise, confirm the results of our study and will also be shown.
Synergized magnetic and gravity measurements probe the detailed structure of the gas giants' deep atmospheres
Authors: Galanti Eli , Kaspi Yohai
Published: October 2020

The strong zonal flows observed at the cloud-level of the gas giants extend thousands of kilometers deep into the planetary interior, as indicated by the Juno and Cassini gravity measurements. However, the gravity measurements alone, which are by definition an integrative measure of mass, cannot constrain with high certainty the detailed vertical structure of the flow below the cloud-level. Here we show that taking into account the recent magnetic field measurements of Saturn and past secular variations of Jupiter's magnetic field, give an additional physical constraint on the vertical decay profile of the observed zonal flows in these planets. In Saturn, we find that the cloud-level winds extend into the planet with very little decay (barotropically) down to a depth of around 7,000 km, and then decay rapidly, so that within the next 1,000 km their value reduces to about 1% of that at the cloud-level. This optimal deep flow profile structure of Saturn matches simultaneously both the gravity field and the high-order latitudinal variations in the magnetic field discovered by the recent measurements. In the Jupiter case, using the recent findings indicating the flows in the planet semiconducting region are order centimeters per second, we show that with such a constraint, a flow structure similar to the Saturnian one is consistent with the Juno gravity measurements. Here the winds extend unaltered from the cloud-level to a depth of around 2,000 km and then decay rapidly within the next 600 km to values of around 1%. Thus, in both giant planets, we find that the observed winds  extend unaltered (baroctropically) down to the semiconducting region, and then decay abruptly. While it is plausible that the interaction with the magnetic field in the semiconducting region is responsible for winds final decay, it is yet to be understood whether another mechanism is involved in the process, especially in the initial decay form the strong 10s meter per seconds winds.
Monitoring the Martian Weather with Areostationary SmallSats
Authors: Montabone Luca , Cantor Bruce , Capderou Michel , Fergason Robin , Feruglio Lorenzo , Forget Francois , Heavens Nicholas , Lillis Robert , Matousek Steve , Smith Michael , Spiga Aymeric , Topputo Francesco , VanWoerkom Michael , Wolff Michael , Young Roland
Published: October 2020

The Martian atmosphere (from the surface up to the outer layers) is a very dynamic system, quickly responding to strong radiative forcing coming from the absorption of solar radiation from dust particles lofted during dust storms. So far, such dynamical phenomena at short time scales and large spatial scales have been observed mainly from spacecraft in polar or quasi-polar orbits, which cannot provide continuous and simultaneous observations over fixed, large regions. This limitation can be bypassed using spacecraft in equatorial, circular, planet-synchronous (i.e. areostationary) orbit at an altitude of 17,031.5 km above the Martian surface. Besides their possible use as communication relays for ground-based assets, for space weather monitoring (they orbit outside Mars' bow shock), and for the study of surface properties (e.g. thermal inertia and albedo), the unique scientific advantages of areostationary satellites for weather monitoring are comparable to those provided by geostationary satellites. These platforms greatly increase the temporal resolution and coverage of single events, and are ideally suited for data assimilation in global climate models. Thanks to NASA PSDS3 program, we have elaborated a mission concept to put a low-cost, low-weight, ESPA-class SmallSat in areostationary orbit, which is capable of supporting various tank sizes in order to provide a wide range of ΔV for three different Mars arrival scenarios. ExoTerra Resource LLC adapted its "Electrically Propelled Interplanetary CubeSat" bus as part of the mission design. Despite the optimization of the flight trajectories and the use of machine learning algorithms to prioritize data downlink, the conclusions of the concept study clearly point towards the current challenges represented by propulsion, communication, and possibly radiation tolerance for scientific SmallSat missions to Mars. Such conclusions are generally common among all low-cost interplanetary SmallSat concepts. Furthermore, a single areostationary satellite is enough to provide a full-disk view to monitor regional dust storms and water ice clouds at specific locations, but cannot provide the global coverage required to understand extreme phenomena such as Martian planetary-scale dust events. For this reason, we have recently started to study a more advanced mission concept involving the use of at least three areostationary satellites. This new study is carried out in collaboration with the Jet Propulsion Laboratory within the scope of a wider NASA-funded project (PMCS program) looking at a constellation concept. The challenge is to keep the areostationary satellite configuration within the ESPA class limits, in order to take advantage of possible future rideshare opportunities.
Comets: Seeing The Bigger Picture – Maximising the Contribution of Amateurs
Authors: Usher Helen , Snodgrass Colin , Roche Paul , Norton Andrew , Angel Tony , Clark Wendy , Yanamandra-Fisher Padma
Published: October 2020

The Rosetta Mission invited amateur astronomers to be part of a ground-based observing campaign for Comet 67P/Churyumov–Gerasimenko.  Amateurs, with greater access to telescope time and wider geographical coverage, can add important temporal coverage and wider scale observations to complement those of professional astronomers. They add the bigger picture. This allows for greater multi-scale analysis of comet activity.This campaign followed on from campaigns in support of the Halley-related and Deep Impact Missions, as well as general comet observing campaigns such as for Comet C/2012 S1 ISON. With 67P coming back shortly, and future comet missions such as Comet Interceptor being planned, there is an opportunity to consider the effectiveness of the 67P amateur campaign, a related 46P/Wirtanen schools’ observing campaign, and draw lessons from these and previous comet and other Pro-Am campaigns to inform good practice for future campaigns.Feedback has been sought, via 3 surveys, from those who took part in the 67P and 46P campaigns, and from amateur astronomers who might be encouraged to take part in future campaigns. The survey results will be presented, along with reflections from some of amateurs involved, and a discussion of how future campaigns may be made most effective.
Interior heating by stellar magnetic fields as a driver of volcanic activity on massive rocky planets
Authors: Kislyakova Kristina , Noack Lena
Published: October 2020

We investigate possible driving mechanisms of volcanic activity on large rocky super-Earths with masses exceeding four Earth masses. Due to high pressures in the mantles of these planets, melting in deep mantle layers can be suppressed, even if the energy release due to tidal heating and radioactive decay is substantial in these areas of the mantles. We investigate if a newly identified heating mechanism, namely induction heating by the star’s magnetic field, can drive volcanic activity on these planets due to its unusual heating pattern close to the planet’s surface, which leads to heat production in the very upper part of the mantle. In this region the pressure is not yet high enough to preclude the melt formation. We use a model for induction heating we developed and apply it to the super-Earth HD 3167b, which has a mass of approximately seven Earth masses. We calculate induction heating in the planet’s interiors assuming an electrical conductivity profile of a hot rocky planet and a moderate stellar magnetic field typical of an old inactive star, which one can expect for HD 3167. Then, we use a mantle convection code (CHIC) to simulate the evolution of volcanic outgassing with time.Fig. 1. Total outgassing of CO2 , CO, H2O, and H2 from HD 3167b assuming the magnetic field of the star of 0, 1, and 5 G. Induction heating leads to a much earlier onset of volcanism on the planet and increases the outgassing by several tens of bar. The mantle viscosity is 10 times the mantle viscosity of the Earth.According to our results, in most cases volcanic outgassing on HD 3167b is not very significant in the absence of induction heating, however, including this heating mechanism changes the picture and leads to a substantial increase in the outgassing from the planet’s mantle. Evolution of volcanic outgassing is illustrated in Fig. 1. Induction heating also leads to a much earlier onset of volcanic activity on this planet. This result shows that induction heating combined with a high surface temperature is capable of driving volcanism on massive super-Earths, which has very important observational implications.
First Study of Photochemical Escape from Proxima Centauri b
Authors: Lee Yuni , Dong Chuanfei
Published: October 2020

As the upper atmospheres of the ‘habitable’ exoplanets orbiting M-Dwarfs are affected by more extreme environments than what Solar System bodies experience, the observations of such exoplanets raise questions to the mass-loss mechanisms and the sustainability of their atmospheres. For the first time, we examine the loss of neutral atmosphere from Proxima Centauri b (PCb) via photochemical mechanisms and formation processes of resulting exoplanetary hot atomic coronae or exospheres.The study is conducted by utilizing our integrated model framework, which couples our 3D Adaptive Mesh Particle Simulator (AMPS) for planetary exospheres and a 3D multi-species magnetohydrodynamic (MHD) model originally developed for Venus and Mars. The coupling of the two models is achieved in one-way, such that the AMPS code incorporates pre-simulated results by the MHD model as inputs for exosphere simulation. The MHD model describes the ionosphere of the planet self-consistently based on the neutral atmosphere adopted for PCb. All simulations in this study assume a Venus-like condition for the ionosphere and thermosphere of PCb, which is also based on an assumption of the absence of an intrinsic dipole magnetic field. As most of the relevant planetary parameters of PCb are unknown, this study provides one possible interpretation of the atmospheric loss process of PCb as well as other exoplanets similar to PCb, which reside in the Habitable Zones (HZs) of M-Dwarfs, to help our understanding of their habitability. 
Formation and dynamics of water clouds on K2-18 b
Authors: Charnay Benjamin , Blain Doriann , Bézard Bruno , Leconte Jérémy , Turbet Martin
Published: October 2020

K2-18 b is a temperate sub-Neptune orbiting in the habitable zone of a nearby M star. Recent analysis of HST transit observations revealed the presence of water vapour and potentially water clouds. K2-18b is a unique opportunity to characterize the physics, chemistry and dynamics of temperate low-mass exoplanets.We present here the results of 3D atmospheric modelling of K2-18b including water clouds with radiative effects. We investigate the effects of atmospheric metallicity (from 1xsolar to 1000xsolar), the concentration of cloud condensation nuclei, microphysics and rotation rate on the distribution of water clouds. We also analyze the impact of clouds and their spatial/time variability on transmission and emission spectra. Finally, we show how future observations with JWST, ELTs and ARIEL would constrain the atmospheric composition and clouds of this planet.
Does topography matter for rocky exoplanets?
Authors: Guimond Claire Marie , Shorttle Oliver , Rudge John F.
Published: October 2020

Topography is a crucial component of the Earth system: having rock exposed to the atmosphere lets surface temperatures self-regulate via silicate weathering, for example. However, there are limits to a lithosphere’s capacity to support mountains or valleys over geologic time. We see in our solar system that the range in a body’s elevations tends to decrease with increasing planet mass. These trends, inherent to planetary building materials, are modelled using well-studied concepts from geodynamics. As a first step, we predict feasible thermal evolutions and dynamic topography scaling relationships for rocky planets, eventually gearing to ask how massive a planet can be and still likely maintain subaerial land.
Virtual tours and exhibits: an innovative tool for education and public outreach in INAF
Authors: Mantovani Giulia , Di Giacomo Federico , Giacomini Livia , Boccato Caterina
Published: October 2020

This critical period we are living worldwide forced us to rearrange our way of engaging general public and students to talk about science. Internet and computers are the most used tools for education and public outreach. INAF (National Institute for Astrophysics) has embraced this new way of interacting with the public by developing virtual tours and exhibits of its museums and telescopes spread all over Italy. In this years, INAF’s researchers, thanks to “Polvere di stelle”, the cultural heritage for Italian astronomy, and the editorial staff of EduINAF, the official INAF online magazine for education, have collected and developed a series of virtual tours of the INAF observatories, telescopes and museums managed by the institute. By staying comfortable at home, general public, students and professors can easily access guided tours, which will fully immerse the users to admire the whole scientific and historic INAF’s heritage. During the presentation, some examples will be displayed to the audience.
A modern digital High Frequency Receiver to explore Uranus and Neptune radio emitters
Authors: Lamy Laurent , Cecconi Baptiste , Dekkali Mustapha ,   LESIA plasma physics group
Published: October 2020

Among the known planetary magnetospheres, those of Uranus and Neptune display very similar radio environments so that they have early been referred to as ‘radio twins’. They produce a variety of electromagnetic radio waves ranging from ~0 to a few tens of MHz similar to - although more complex than - those of Saturn or the Earth (Desch et al., 1991, Zarka et al., 1995). These include the well known Uranian/Neptunian Kilometric Radiations (UKR/NKR) below 1MHz or the Uranian/Neptunian Electrostatic Discharges (UED/NED) beyond, which remain only known from Voyager 2 radio observations. Here, we present a modern concept of digital High Frequency Receiver (HFR) within the frame of a general Radio and Plasma Wave (RPW) experiment retained in various mission concepts toward Uranus and Neptune (e.g. Hess et al., 2010 ; Arridge et al., 2011, 2013, 2014 Christophe et al., 2011; Masters et al., 2013; Hofstadter at al., 2019). The presented HFR concept, based on the heritage of Cassini/RPWS/HFR, Bepi-Clompobo/PWI/Sorbet, Solar Orbiter/RPW and JUICE/RPWI/JENRAGE is aimed at providing a light, robust, low-consumption versatile instrument capable of goniopolarimetric and waveform measurements from a few kHz to ~20MHz, devoted to the study of auroral and atmospheric radio and plasma waves or dust impacts.
The EU H2020 programme NEOROCKS
Authors: Dotto Elisabetta , Banaszkiewicz Marek , Banchi Sara , Barucci Maria A. , Bernardi Fabrizio , Birlan Mirel , Carry Benoit , Cellino Alberto , De Leon Julia , Lazzarin Monica , Mazzotta Epifani Elena , Nomen Torres Jaime , Perna Davide , Perozzi Ettore , Pravec Petr , Sánchez Ortiz Noelia , Snodgrass Colin , Teodorescu Claudiu ,   NEOROCKS team
Published: October 2020

The research about Near Earth Objects (NEOs) is a major topic in planetary science. One reason is the potential hazard some of them pose to human beings and, more in general, to life on our planet. Moreover, the physical characterization of NEOs allows us to put constraints on the material accreted in the protoplanetary nebula at different solar distances and can give us insights into the early processes  that  governed  the  formation and the evolution of planets - including the delivery of water and organics to Earth -, and into further evolutionary processes that acted on asteroid since their formation - such as collisions and non-gravitational effects.The “NEOROCKS - The NEO Rapid Observation, Characterization and Key Simulations” Collaborative Research Project has been recently approved to address the topic c) “Improvement of our knowledge of the physical characteristics of the NEO population” of the call SU-SPACE-23-SEC-2019 from the Horizon 2020 - Work Programme 2018-2020 Leadership in Enabling and Industrial Technologies – Space.The aims of NEOROCKS are:to develop and validate advanced mathematical methods and innovative algorithms for NEO orbit determination and impact monitoring;
to organize follow-up astronomical observations of NEOs efficiently, in order to obtain high-quality data needed to derive their physical properties, giving priority to timely addressing potentially hazardous objects;
to improve dramatically statistical analysis, modelling and computer simulations aimed to understand the physical nature of NEOs, focussing on small size objects, which are of uttermost importance for designing effective impact mitigation measures in space and on the ground;
to ensure maximum visibility and dissemination of the data beyond the timeline of the project, by hosting it in an existing astronomical data center facility;
to foster European and international cooperation on NEO physical characterization, providing scenarios and roadmaps with the potential to scale-up at a global level the experience gained during the project;
to apply and guarantee continuity of educational and public outreach activities needed to improve significantly public understanding and perception of the asteroid hazard, counteracting the spreading of “fake news” and unjustified alarms.
Acknowledgement: This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 870403 (project NEOROCKS).
New Dynamical Mass Estimates of the beta Pictoris Planetary System Through Gaussian Process Stellar Activity Modelling
Authors: Vandal Thomas , Rameau Julien , Doyon René
Published: October 2020

Nearly 15 years of radial velocity (RV) monitoring and direct imaging (DI) enabled the detection oftwo giant planets orbiting the young, nearby star β Pictoris. The δ Scuti pulsations of the star, overwhelming planetary signals, need however to be carefully suppress. In this talk, we propose a new and independent analysis of the system, making use of all available data, including photometric light curve from the ground and space, long term RV and DI monitoring. We demonstrate how all data can be consistently modelled in a Bayesian framework. We show how modern and physically motivated kernels for Gaussian Process can effectively model complex stellar activity. Using further carefull statistical treatment of the data to extend the monitoring, we detect both planets from RV data only for the first time. To characterize the system more accurately, we also perform a joint fit of all available relative astrometry and RV data. We provide precise orbital parameters and discuss the whole system architecture. The inferred dynamical mass measurements for both planets are also compared to mass-luminosity evolutionary tracks. This work opens the path towards a precise characterization of young planetary systems combing photometry, spectroscopy, and astrometry.
Induced magnetic moments for near-spherical oceans: New methods for constraining ocean shape
Authors: Styczinski Marshall , Harnett Erika
Published: October 2020

Magnetic induction has proven to be a powerful tool in the exploration and characterization of structure in planetary subsurfaces. This is especially true in the case of Europa, where perhaps the best evidence for an extant subsurface ocean comes from identification of magnetic moments that vary with time. Past investigations, however, have been limited by available techniques for calculating induced magnetic fields based on a supposed internal structure, an important prerequisite to the determination of ocean properties by way of magnetic exploration. Critically, existing techniques permit only a spherically symmetric interior structure. In this work, we expand the ice−ocean boundary in terms of spherical harmonics and derive changes to the induced magnetic moments for a given boundary shape. We also demonstrate the application of this technique to Europa for the purpose of constraining the shape of its conducting ocean.
Biases in TPM-derived Diameters for High-Eccentricity NEAs
Authors: MacLennan Eric , Granvik Mikael
Published: October 2020

Estimation of asteroid sizes from the observed thermal emission are performed by comparing the flux modeled from simple thermal models and thermophysical models (TPMs). The accuracy of the diameter estimate is dependent on the accuracy of the modeled surface temperatures, which are calculated differently among these models. Simple thermal models, like the often-chosen NEATM, do not account for subsurface heat conduction whereas thermophysical models explicitly account for it. This neglect of heat transport can, generally speaking, result in the overestimation of diameters when simple thermal models are used (Spencer, et al. 1989) because nighttime thermal emission is neglected by simpe thermal models (the NESTM model being the exception). Mommert et al. (2019) showed that NEATM diameter fits to NEAs are reasonably accurate (i.e. little systematic bias) when the solar phase angle of observation is 65°. On the other hand, TPMs are thought to provide highly accurate diameters regardless of the observing circumstances or physical properties of the surface because they include heat conduction.Nearly all TPMs compute surface temperatures over a diurnal timescale, over which the solar energy input is held constant. However, as the case with high-eccentricity NEAs, a potentially overlooked effect on diameter determination is the influence of rapidly-change in solar heating. Because these objects experience large, rapid changes in the amount of absorbed sunlight, heat conducted into the subsurface at small heliocentric distances will affect surface tempertures at larger heliocentric distances. Figure 1 below demonstrates that this effect is more pronounced for larger orbital eccentricities.Figure 1. Discrepancy (orbTPM-diTPM) in the maximum daily temperature at different heliocentric distances for a hypothetical asteroid with varying orbital eccentricity. Dots indicate time steps separated by ~2 days. Open circles show the median values of temperature discrepancy and heliocentric distance. A positive value for the discrepancy indicates a larger orbTPM temperature.In this work we compare two TPMs: one with a fixed solar energy input over a diurnal timescale, diTPM, and another that models surface temperatures over an entire orbit, orbTPM. We compare the disk-integrated fluxes of each model in order to investigate and characterise any discrepancy. Emitted thermal flux is directly proportional to size, thus the flux discrepancy between the two models is used to quantify any bias in diameter determination when the diTPM is used.The potential effects of thermal inertia, rotation period, spin axis, and phase angle on this discrepancy are considered. Finally, we employ the orbTPM on a few asteroids observed in the thermal infrared and postulate on the implications on thermal modelling of NEAs as a population.
A First Comparison Between Ionospheric and Surface Level Magnetic Fields at Mars
Authors: Fillingim Matthew , Johnson Catherine , Mittelholz Anna , Langlais Benoit , Russell Christopher , Joy Steve , Chi Peter , Lillis Robert , Espley Jared , Smrekar Sue , Banerdt Bruce , Jakosky Bruce
Published: October 2020

With both the Mars Atmosphere and Volatile Evolution (MAVEN) mission and the Interior Exploration using Seismic Investigations, Geodesy and Heat Transport (InSight) mission concurrently operating at Mars, we are able to make two point comparisons of the vector magnetic field at Mars for the first time. During MAVEN overflights of the InSight landing site, we compared deviations in the ionospheric magnetic field to variations in the surface level magnetic field. We find significant orbit to orbit variability in the magnitude and direction of the ionospheric magnetic field as well as significant day to day variability of the surface level magnetic field. We attribute this variability to time varying ionospheric currents. However, when analyzing the ensemble of 16 individual MAVEN overflights of the InSight landing location, we see no clear correlation between the magnitudes or directions of the ionospheric magnetic field and the surface magnetic field as might be expected. If the presumed ionospheric currents have a small scale size, then the ionospheric magnetic field will display increased variability as MAVEN flies through the current structure. Whereas the present analysis is restricted to mostly nightside MAVEN overflights where current are expected to be weak, future analyses should incorporate dayside overflights where current are expected to be stronger and current signatures more clear.
Lidar measurements of yawed-wind-turbine wakes: characterization and validation of analytical models
Authors: Brugger Peter , Debnath Mithu , Scholbrock Andrew , Fleming Paul , Moriarty Patrick , Simley Eric , Jager David , Roadman Jason , Murphy Mark , Zong Haohua , Porté-Agel Fernando
Published: October 2020

Abstract. Wake measurements of a scanning Doppler lidar mounted on the nacelle of a full-scale wind turbine during a wake-steering experiment were used for the characterization of the wake flow, the evaluation of the wake-steering set-up, and the validation of analytical wake models. Inflow-scanning Doppler lidars, a meteorological mast, and the supervisory control and data acquisition (SCADA) system of the wind turbine complemented the set-up.
Results from the wake-scanning Doppler lidar showed an increase in the wake deflection with the yaw angle and that the wake deflection was not in all cases beneficial for the power output of a downstream turbine due to a bias of the inflow wind direction perceived by the yawed wind turbine and the wake-steering design implemented. Both observations could be reproduced with an analytical model that was initialized with the inflow measurements. Error propagation from the inflow measurements that were used as model input and the power coefficient of a waked wind turbine contributed significantly to the model uncertainty. Lastly, the span-wise cross section of the wake was strongly affected by wind veer, masking the effects of the yawed wind turbine on the wake cross sections.