bluuebunny/crossref_metadata_2025 huggingface dataset:
How to identify exoplanet surfaces using atmospheric trace species in hydrogen-dominated atmospheres
Authors: Yu Xinting , Moses Julianne , Fortney Jonathan , Zhang Xi
Published: July 2021

Sub-Neptunes (Rp~1.25-4 REarth) remain the most commonly detected exoplanets to date. However, it remains difficult for observations to tell whether these intermediate-sized exoplanets have surfaces and where their surfaces are located. Here we propose that the abundances of trace species in the visible atmospheres of these sub-Neptunes can be used as proxies for determining the existence of surfaces and approximate surface conditions. As an example, we used a state-of-the-art photochemical model to simulate the atmospheric evolution of K2-18b and investigate its final steady-state composition with surfaces located at different pressures levels (Psurf). We find the surface location has a significant impact on the atmospheric abundances of trace species, making them deviate significantly from their thermochemical equilibrium and “no-surface” conditions. This result arises primarily because the pressure-temperature conditions at the surface determine whether photochemically-produced species can be recycled back to their favored thermochemical-equilibrium forms and transported back to the upper atmosphere. For an assumed H2-rich atmosphere for K2-18b, we identify seven chemical species that are most sensitive to the existence of surfaces: ammonia (NH3), methane (CH4), hydrogen cyanide (HCN), acetylene (C2H2), ethane (C2H6), carbon monoxide (CO), and carbon dioxide (CO2). The ratio between the observed and the no-surface abundances of these species, can help distinguish the existence of a shallow surface (Psurf < 10 bar), an intermediate surface (10 bar < Psurf < 100 bar), and a deep surface (Psurf > 100 bar). This framework can be applied together with future observations to other sub-Neptunes of interest.Figure 1: Selected criteria and a flowchart of possible steps to identify the existence of the surface and the surface pressure for a hydrogen-dominated exoplanet with properties similar to K2-18b.
Alfnoor: a population study on Ariel's low resolution transmission spectra.
Authors: Mugnai Lorenzo V. , Al-Refaie Ahmed , Bocchieri Andrea , Changeat Quentin , Pascale Enzo , Tinetti Giovanna
Published: July 2021

In the next decade, the Ariel Space Telescope will provide the first statistical data set of exoplanet spectra, performing spectroscopic observations of about 1000 exoplanets in the wavelength range 0.5 - 7.8 micron during its Reconnaissance Survey. The Ariel Reconnaissance Survey has been designed specifically to identify planets without molecular features in their atmosphere, and select targets (about 500) for accurate chemical characterisation with higher SNR spectroscopic observations.In this work, we investigate the information content of Ariel's Reconnaissance Survey low resolution transmission spectra. We produce different planetary populations using the Ariel candidate target list, randomizing the planetary atmospheres, and simulating the Ariel observations using the Alfnoor software. Then we analyse the dataset, getting three different results:(1) We present a solid strategy that will allow selecting candidate planets to be reobserved in an Ariel's higher resolution, using a chi-squared based metric to identify the flat spectra.(2) Because the reconnaissance survey is not optimised for spectral retrieval, we propose a novel model-independent metric to preliminary classify exoplanets by their atmospheric composition. Without any other planetary information than the spectrum, our metric proves capable of indicating the presence of a molecule when its abundance in the atmosphere is in excess of 10-4 in mixing ratio.(3) We introduce the possibility of finding other methods to better exploit the data scientific content. We report as an example of possible strategies, a preliminary study involving Deep and Machine Learning algorithms. We show that their performance in identifying the presence of a certain molecule in the spectra is marginally better than our metric for some of these algorithms, while others outperform the metric. We conclude that the the Ariel reconnaissance survey is effective in detecting exoplanets manifesting featureless spectra, and we further show that the data collected in this observing mode have a rich scientific content, allowing for a first chemical classification of the observed targets.
ARES V: No Evidence For Molecular Absorption in the HST WFC3 Spectrum of GJ 1132 b
Authors: Mugnai Lorenzo V. , Modirrousta-Galian Darius , Edwards Billy ,   ARES V team
Published: July 2021

We present a study on the spatially scanned spectroscopic observations of the transit of GJ 1132 b, a warm (~500 K) Super-Earth (1.13 Re) that was obtained with the G141 grism (1.125 - 1.650 micron) of the Wide Field Camera 3 (WFC3) onboard the Hubble Space Telescope. We used the publicly available Iraclis pipeline to extract the planetary transmission spectra from the five visits and produce a precise transmission spectrum. We analysed the spectrum using the TauREx3 atmospheric retrieval code with which we show that the measurements do not contain molecular signatures in the investigated wavelength range and are best-fit with a flat-line model. Our results suggest that the planet does not have a clear primordial, hydrogen-dominated atmosphere. Instead, GJ 1132 b could have a cloudy hydrogen-dominated envelope, a very enriched secondary atmosphere, be airless, or have a tenuous atmosphere that has not been detected. Due to the narrow wavelength coverage of WFC3, these scenarios cannot be distinguished yet but the James Webb Space Telescope may be capable of detecting atmospheric features, although several observations may be required to provide useful constraints
The terrestrial radiation belts as seen by BepiColombo during its flyby to Earth
Authors: Sanchez-Cano Beatriz , Vainio Rami , Pinto Marco , Oleynik Philipp , Nakamura Rumi , Moissl Richard , Miyoshi Yoshizumi , Marques Arlindo , Lehtolainen Arto , Korpela Seppo , Kilpua Emilia , Johnson Rosie , Huovelin Juhani , Heyner Daniel , Hajdas Wojtek , Grande Manuel , Gonçalves Patricia , Esko Eero , Dandouras Iannis
Published: July 2021

BepiColombo is a joint mission of the European Space Agency (ESA) and the Japan Aerospace Exploration Agency (JAXA) to the planet Mercury, that was launched in October 2018 and it is due to arrive at Mercury in late 2025. It consists of two spacecraft, the Mercury Planetary Orbiter (MPO) built by ESA, and the Mercury Magnetospheric Orbiter (MMO) built by JAXA, as well as a Mercury Transfer Module (MTM) for propulsion built by ESA. The cruise phase to Mercury will last ~7 years and constitutes an exceptional opportunity for studying the evolution of the solar wind, solar transients, as well as for planetary science and planetary space weather. Some important aspects to consider during the cruise are the close distances to the Sun that BepiColombo will face, the near half-solar activity cycle that will cover, as well as the several flybys to Earth, Venus and Mercury that will perform. So far, BepiColombo has accomplished a flyby to Earth in April 2020 and a flyby to Venus in October 2020, with a second flyby to Venus programmed for August 2021 and the first Mercury flyby in October 2021.This work focuses on the flyby to Earth, and in particular, on the radiation belt observations performed by several instruments onboard BepiColombo. The flyby occurred on 10 April 2020 under relatively steady solar wind conditions. BepiColombo crossed the outer radiation belt on the terrestrial dawn side when moving from the day side to the night side. It skimmed the inner radiation belt on the night side sector after dawn, and then crossed again the outer belt at night (behind the dusk terminator region). Two instruments onboard the MPO spacecraft were able to take measurements of the belts: the BepiColombo Radiation Monitor (BERM) and the Solar Intensity X-Ray and Particle Spectrometer (SIXS). In this work, we report the particle species, radiation and energies observed by these two instruments, as well as we perform a cross-calibration of their detections, which is an important activity in preparation for joint-observations of the Hermean environment. Moreover, using magnetic field observations from MPO-MAG, we also investigate the trajectory of the particles within the radiation belts. This work is complemented with data from other missions that give us the state of the terrestrial system and frame our observations into the right context. It includes data from Cluster-II, Themis, and Arase/ERG missions.
The equatorial wind structure in Jupiter’s stratosphere from direct wind and temperature measurements with ALMA and IRTF/TEXES
Authors: Benmahi Bilal , Cavalié Thibault , Greathouse Thomas K. , Hue Vincent , Giles Rohini , Guerlet Sandrine , Spiga Aymeric , Cosentino Richard
Published: July 2021

Since 30 years, an equatorial oscillation of the temperature structure with a quasi-period of 4 years has been discovered in the atmosphere of Jupiter (Orton et al. 1991, Leovy et al. 1991). This phenomenon results in a complex vertical and horizontal structure of prograde and retrograde jets. However, the wind structure of the stratosphere in the equatorial zone of Jupiter has not been measured directly. It has only been inferred in the tropical region from the thermal wind balance using temperatures measured in the jovian stratosphere and the cloud-top wind speeds measured as a initial condition (e.g. Flasar et al. 2004). But temperatures are not constrained between the upper troposphere and the middle stratosphere from observations, limiting thus the accuracy of the thermal wind balance.In this study, we derive self-consistently for the first time the structure of the tropical winds by utilizing wind and temperature observations all performed in the stratosphere. The wind speeds were obtained by Cavalié et al. (2021) at 1 mbar in Jupiter's stratosphere in both the equatorial and tropical regions in March 2017 with ALMA. The stratospheric thermal field was measured a few days before from the equator to the mid-latitudes with Gemini/TEXES (Giles et al. 2020). For the derivation of the wind, we use both the thermal wind equation (Pedlosky 1979) and the equatorial thermal wind equation (Marcus et al. 2019). In this paper, we will present and discuss our results.
Automatic prediction, selection and analysis of occultations to characterize asteroid family members
Authors: Leiva Rodrigo , Tanga Paolo , Liberato Luana
Published: July 2021

A new 50 cm telescope, the UniversCity telescope, was recently installed at Plateau de Calern, France, to survey stellar occultation by asteroids from collisional families. A stellar occultation occurs when an asteroid passes in front of a distant star blocking its light temporarily. Measuring the time of the occultations provides an accurate astrometric measurement of the asteroid, comparable with the angular size of the asteroid. Thanks to the astrometric catalog from the Gaia mission, astrometry accuracy from occultation reaches a few milliarcseconds.The astrometry from the survey is used in turn to improve the orbit of the asteroid, while the duration of the occultation is used to constrain physical characteristics and search for binarity. The orbit improvement aims to detect and measure the drift rate in the orbital elements of asteroids due to the Yarkovsky effect, a non-gravitational force responsible for scattering the orbital elements of collisional family members. Combining the magnitude of the Yarkovsky drift rate from the occultation survey with the accumulated drift since the originating collision, the age determination of the collisional family can be obtained.The occultation survey takes advantage of the stellar occultation technique and the Gaia astrometric catalog to systematically derive accurate astrometric measurements for collisional family members.The telescope will be operated robotically, dedicating most of its time to the occultation survey, with a small percentage of time to other science cases. The large number of family members and candidates to stellar occultations demands the automation of the occultation prediction, the selection and prioritization of occultation events, telescope scheduling, data reduction, and data analysis.The occultation predictions are updated regularly in the light of new astrometric measurements from traditional astrometry and from occultations measurements. The occultations predicted to be visible from the UniversCity site are prioritized based on their chances of detection and contribution to the family age determination. The data acquired each night is automatically reduced to obtain light curves from which detection candidates are analyzed.We will present the status of the project and the development and performances of the automatic prediction and processing system.
First direct measurements of the zonal winds in Saturn's stratosphere
Authors: Cavalié Thibault , Benmahi Bilal , Fouchet Thierry , Moreno Raphael , Lellouch Emmanuel , Guerlet Sandrine , Spiga Aymeric , Moullet Arielle
Published: July 2021

Saturn's cloud-top zonal winds have been measured since the Voyager days. Contrary to Jupiter, the jets are mostly prograde and with a noticeable broad super-rotating jet between 35°S and 35°N with peak velocities reaching ~450 m/s between 10°S and 10°N (e.g. Sanchez-Lavega et al. 2000). The Cassini mission revealed, during its Grand Finale, that these winds extend as deep as 8000 km below the clouds (Galanti et al. 2019). Above the tropopause, in the stratosphere, there has been no direct determination of the zonal winds, although thermal wind balance calculations have shown the signature of Saturn's semi-annual oscillation (SAO) in the tropical zone (Fouchet et al. 2008, Guerlet et al. 2011, 2018). These derivations lack an initial condition, in terms of wind speeds, located in the sensitivity zone of the temperature measurements. It thus remains unknown if the SAO jets alternate in direction as a function of altitude. In addition, more and more sophisticated general circulation models are being developed to constrain the dynamics of Saturn's stratosphere (Friedson & Moses 2012, Spiga et al. 2020, Bardet et al. 2021). These models now crucially need observational constraints.We used the Atacama Large Millimeter/submillimeter Array (ALMA) to map Saturn's stratospheric zonal winds. We derive the zonal winds as a function of latitude from the Doppler shifts induced by the winds on the spatially and spectrally resolved spectral lines. In this paper, we will present and discuss our results.
PAOS, the Physical Optics Propagation model of the Ariel optical system
Authors: Bocchieri Andrea , Pascale Enzo
Published: July 2021

Ariel, the Atmospheric Remote-sensing Infrared Exoplanet Large-survey, is a medium-class space mission part of ESA's Cosmic Vision programme, due for launch in 2029. Ariel will survey a diverse sample of about 1000 extrasolar planets in the visible and infrared spectrum to answer questions about their composition, formation and evolution. Ariel mounts an off-axis Cassegrain telescope with an 1100 mm x 730 mm elliptical mirror and has two separate instruments (FGS and AIRS) that cover the 0.5-7.8 micron spectral range. To study the Ariel optical performance and related systematics, we developed PAOS, the Physical Ariel Optics Simulator, an End-to-End physical optics propagation model of the Ariel Telescope and subsystems. PAOS is a Python code that consists of a series of functions and procedures that reproduces the Ariel optical design. Using PAOS, we can investigate how diffraction affects the electromagnetic wavefront as it travels through the Ariel optical systems and the resulting PSFs in the photometric and spectroscopic channels of the mission. This enables to perform a large number of detailed analyses, both on the instrument side and on the optimisation of the Ariel mission. In particular, PAOS can be used to support the requirement on the maximum amplitude of the aberrations for the manufacturing of the Ariel primary mirror, as well as to develop strategies for in-flight calibration, e.g. focussing procedures for the FGS and AIRS focal planes, and to tackle systematics such as pointing jitter and vignetting. With the Ariel mission now in the process of finalizing the instrument design and the data analysis techniques, PAOS will greatly contribute in evaluating the Ariel payload performance with models to be included in the existing Ariel simulators such as ArielRad, the Ariel Radiometric model, and ExoSim, the Exoplanet Observation simulator, for the purpose of studying and optimising the science return from Ariel.
Gravitational atmospheric tides as a probe of Titan’s interior: application to Dragonfly
Authors: Charnay Benjamin , Tobie Gabriel , Lebonnois Sébastien , Lorenz Ralph
Published: July 2021

Just as Saturn’s massive gravity causes tides both in Titan’s interior as well as its surface seas, it causes a tide in the atmosphere (Lorenz 1992; Tokano & Neubauer 2002). Previous modelling work with a 3D Global Climate Model found that gravitational tides should produce a surface pressure variation of ∼1.5 hPa through the orbit of Titan and tidal winds in the troposphere (Tokano & Neubauer 2002). Here, we revisit gravitational atmospheric tides on Titan with analytical calculations and with a 3D Global Climate Model (the IPSL-Titan GCM). We show that the surface pressure field quickly adjust to the tidal potential, strongly decreasing the amplitude of tidal winds. We analyze the impact of the deformation of Titan’s interior and crust on the amplitude of the tidal pressure variations. Finally, we discuss how measurements of pressure variations by Dragonfly could help to constrain Titan’s interior and crust.
S+ Implantation in Oxide Ices: Relevance to Europa
Authors: Mifsud Duncan V. , Kaňuchová Zuzana , Herczku Péter , Juhász Zoltán , Kovács Sándor T. S. , Sulik Béla , Hailey Perry A. , Traspas Muiña Alejandra , Ioppolo Sergio , McCullough Robert W. , Mason Nigel J.
Published: July 2021

The implantation of reactive charged species within low-temperature solids is relevant to astrochemistry and may lead to physico-chemical changes within the solid, such as the formation of new molecules which incorporate the projectile. We have performed the high-fluence (>1016 ions cm–2) implantation of S+ into CO, CO2 and H2O ices at 20 and 70 K. Our results show that implantation into CO and CO2 results in the formation of SO2 at 20 K, although no evidence of SO2 was observed at 70 K. Implantation into H2O yields H2SO4 hydrates. These results are applicable to Europa; one of the Galilean moons of Jupiter.
Thermal and dynamical effects around rocklines in the innermost regions of the protosolar nebula
Authors: Aguichine Artyom , Mousis Olivier , Devouard Bertrand , Ronnet Thomas
Published: July 2021

In our solar system, terrestrial planets and meteoritical matter exhibit various bulk compositions. To understand this variety of compositions, formation mechanisms of meteorites are usually investigated via a thermodynamic approach that neglects the processes of transport throughout the protosolar nebula. Here, we investigate the role played by rocklines (condensation/sublimation lines of refractory materials) in the innermost regions of the protosolar nebula (PSN) to compute the composition of particles migrating inward as a function of time. To do so, we utilize a one-dimensional accretion disk model with a prescription for dust and vapor transport, sublimation, and recondensation of refractory materials [1]. Figure 1 shows the computed composition of the PSN in the Mg-Fe-Si ternary diagram, and Figure 2 shows the same profiles but where we represent the Fe wt% as a function of heliocentric distance. We find that the diversity of the bulk composition of cosmic spherules, chondrules, and chondrites can be explained by their formation close to rocklines. This suggests that solid matter is concentrated in the vicinity of these sublimation/condensation fronts. Although our model only focuses on the most abundant refractory species (ferrosilite, enstatite, fayalite, forsterite, iron sulfide, kamacite, nickel) and relevant thermodynamic data, it suggests that rocklines played a major role in the formation of small and large bodies in the innermost regions of the protosolar nebula. The increase in iron abundance close to iron alloys rocklines gives some hints on the origin of dust particles that formed Mercury’s large core.Figure 1. Composition profiles of the PSN in a Mg-Fe-Si ternary diagram (expressed in mass fraction) at different times, with composition of glass cosmic spherules (S–V type), barred olivine spherules (S-BO type), porphyritic spherules (S-P type) and C-chondrules. Protosolar and Earth’s compositions are represented by Sun’s and Earth’s symbols, respectively, and Mercury’s composition is represented by a red circle. Figure 2. Same as Figure 1, but here the Fe wt% is represented as a function of heliocentric distance. Color boxes correspond to typical compositions of chondrules (0%–10%), glass cosmic spherules (10%–30%), and porphyritic and barred olivine cosmic spherules (30%–60%).[1] Aguichine, A., Mousis, O., Devouard, B., and Ronnet, T. 2020, ApJ, 901, 97. 
The solar system data in the forthcoming Data Release 3 by the Gaia mission of ESA: a preview
Authors: Tanga Paolo
Published: July 2021

The Data Release 3 by the Gaia mission (ESA) will not only multiply by a large factor the volume of observations, but will also add more quality and complexity. With respect to DR2, that appeared in 2018. The number of asteroids with astrometry and photometry will be multiplied by a factor >10, and data will span a longer time interval. Also, for the first time a set of reflectance spectra for several thousand asteroids will be released. Some planetary satellites and candidate new asteroids will also be included. The improvement in volume, accuracy and variety of data will add new dimensions to the contribution of Gaia to asteroid science as this will probably be the most extensive and self consistent set of visible spectra available up to know. In this talk, we will mainly focus on the general properties of the asteroid data in DR3 (statistics on the sample) and on the improvement in astrometry with respect to DR2. Based on the results obtained from the exploitation of DR2, we will review the expected impact of DR3 in terms of improved orbits, Yarkovsky determination, prediction of asteroid occultations. The properties of asteroid spectra in DR3 will be presented in another contribution to this meeting by M. Delbo'. 
The Europlanet Evaluation Toolkit
Authors: Heward Anita , DeWitt Jen
Published: July 2021

Evaluation can provide essential information in understanding the effectiveness and accessibility of outreach activities in engaging diverse communities.
In this presentation, we will give an overview of the Europlanet Evaluation Toolkit, a resource that aims to empower outreach providers and educators in measuring and appraising the impact of their activities. The toolkit is intended to provide advice and resources that can be simply and easily integrated into normal outreach and education activities. It is available as an interactive online resource at http://www.europlanet-eu.org/europlanet-evaluation-toolkit/, as a downloadable PDF and as a hard copy (including a book and set of activity cards).
The toolkit has been developed over a number of years with content provided by professional outreach evaluators Karen Bultitude and Jennifer DeWitt (UCL, UK). Initially, a series of focus groups and scoping discussions were held with active outreach providers from the planetary science community in order to determine what they wanted from such a toolkit, and what sort of tools would be of most interest. A shortlist of tools was developed based on these discussions, with volunteers testing out the tool instructions once they were drafted.

The toolkit begins with a brief introduction to evaluation and steps to choosing the right tools. This advice takes the form of a series of questions to help design an evaluation approach and make the most efficient and effective use possible of limited time and resources.
The toolkit offers a choice of 14 data collection tools that can be selected according to the audience (e.g. primary, secondary, interested adult, general public), the type of environment and activity (e.g. drop-in, interactive workshop, ongoing series, lecture/presentation or online) or according to when they might best be used (during, beginning/end, or after an event). The online version of the toolkit includes a set of interactive tables to help with the selection of which tool is most appropriate for any given situation.
The toolkit includes descriptions and worked examples of how to use two techniques (word-clouds and thematic coding) to analyse the data, as well as some top tips for evaluation and recommended resources.
For some of the tools, case study examples include information about how the tools have been used in the context of an event, how data was actually collected and analysed and what conclusions were reached, based on the data gathered.
Over the past year, videos and training resources for using the toolkit have been added, as well as virtual alternatives to the physical tools.
The Europlanet Evaluation Toolkit has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 871149 (Europlanet 2024 RI) and 654208 (Europlanet 2020 RI).
A Langmuir Probe – fluxgate magnetometer combination for Comet Interceptor
Authors: De Keyser Johan , Ranvier Sylvain , Maes Jeroen , Pawlak Jordan , Neefs Eddy , Dhooghe Frederik , Auster Uli , Chares Bernd , Edberg Niklas , Fredriksson Jesper , Puccio Walter , Henri Pierre , Le Duff Olivier , Peterson Joakim , Oja Magnus
Published: July 2021

ESA’s Comet Interceptor mission is a low budget, fast track mission to a dynamically new comet (DNC). As a DNC enters the inner solar system for the first time, it is expected to feature strong activity and to display a fluid-scale plasma environment, rather than the kinetic-scale environment encountered at weakly active objects such as 67P.  In situ characterization of this plasma environment is therefore one of the main mission objectives and is the object of the Dust-Fields-Plasma instrument, a suite of sensors for the measurement of the dust, the plasma populations, and the magnetic and electric fields and waves, with the field sensors being mounted on booms, all within strict mass, power, and budget constraints. In this context a sensor has been developed that harbors a fluxgate magnetometer at the center of a hollow spherical Langmuir probe. Precautions have been taken to minimize the possible interference between both, while at the same time being very lightweight. An engineering model has been built, tested and characterized in detail. Together with a companion Langmuir probe and an additional magnetometer in gradiometer configuration, the probe-magnetometer combination (COMPLIMENT + FGM) provides data regarding magnetic and electric fields and waves, total ion and electron densities and electron temperature, as well as the ambient nanodust population. It also offers reference data for the other sensors, such as magnetic field direction, spacecraft potential and total plasma density at high cadence, and integrated EUV flux.
Atmospheres on Callisto composed of sublimated water vapor and its photochemical products
Authors: Carberry Mogan Shane , Tucker Orenthal , Johnson Robert , Vorburger Audrey , Galli Andre , Roth Lorenz , Tafuni Angelo , Kumar Sunil , Sahin Iskender , Sreenivasan Katepalli
Published: July 2021

The parameter space for the very uncertain composition of sublimated H2O and its photochemical products H and H2 in Callisto's atmosphere is examined using the Direct Simulaton Monte Carlo (DSMC) method.We focus on two significantly different versions of H2O production in which:(1) the ice and dark, non-ice/ice-poor material are intimately mixed and H2O sublimates at Callisto's warm day-side temperatures (e.g., as in most atmospheric modeling efforts at Callisto to date [1-4]); and(2) the ice and dark, non-ice/ice-poor material are segregated (e.g., consistent with interpretations of images of Callisto's surface taken by Voyager [5, 6] and Galileo [7]) and H2O sublimates at "ice" temperatures [8].Our 2D molecular kinetic models track the motion H2O, whose sublimation yield varies several orders of magnitude depending on the description of Callisto's surface, its photochemical products H and H2, and a relatively dense O2 component. Whereas H is assumed to react in the regolith on return to the surface, H2 is assumed to thermalize and re-enter the atmosphere.We compare the simulated LOS column densities of H to the detected H corona at Callisto [9], which was suggested to be produced primarily by photodissociation of sublimated H2O. Our goal is to use the corona observations to help constrain the source rate for H2O from Callisto’s complex surface.References[1] Liang et al., 2005. Atmosphere of Callisto. Journal of Geophysical Research: Planets.[2] Vorburger et al., 2015. Monte-Carlo simulation of Callisto’s exosphere. Icarus.[3] Hartkorn et al., 2017. Structure and density of Callisto’s atmosphere from a fluid-kinetic model of its ionosphere: Comparison with Hubble Space Telescope and Galileo observations. Icarus.[4] Carberry Mogan et al., 2021 (under review). A tenuous, collisional atmosphere on Callisto. Icarus.[5] Spencer and Maloney, 1984. Mobility of water ice on Callisto: Evidence and implications. Geophysical Research Letters.[6] Spencer, 1987. Thermal segregation of water ice on the Galilean satellites. Icarus.[7] Moore et al., 1999. Mass movement and landform degradation on the icy Galilean satellites: Results of the Galileo nominal mission. Icarus.[8] Grundy et al., 1999. Near-infrared spectra of icy outer solar system surfaces: Remote determination of H2O ice temperatures. Icarus.[9] Roth et al., 2017. Detection of a hydrogen corona at Callisto. Journal of Geophysical Research: Planets.
Solar Orbiter’s first Venus flyby: observations from the Radio andPlasma Wave instrument
Authors: Hadid Lina ,   Solar Orbiter's RPW, MAG and EPD teams
Published: July 2021

On December 27, 2020, Solar Orbiter completed its first gravity assist manoeuvre of Venus. While this flyby was performed to provide the spacecraft with sufficient velocity to get closer to the Sun and observe its poles from progressively higher inclinations, the Radio and Plasma Wave (RPW) consortium, along with other operational in-situ instruments, had the opportunity to perform high cadence measurements and study the plasma properties in the induced magnetosphere of Venus. In this work we present an overview of the in situ observations performed by RPW, inside the induced magnetosphere of Venus, during this first encounter of Solar Orbiter.These data allowed conclusive identification of various waves at low and higher frequencies than previously observed and detailed investigation regarding the structure of the induced magnetosphere of Venus. Furthermore, noting that prior studies were mainly focused on the magnetosheath region and could only reach 10-12 Venus radii (RV) down the tail, the particular orbit geometry of Solar Orbiter’s VGAM1, allowed the first investigation of the nature of the plasma waves continuously from the bow-shock to the magnetosheath, extending to ∼ 70 R V in the far distant tail region.
3D Modeling of Supersaturated H2O/H2O2 on Early Mars Climate during the Noachia
Authors: Delavois Antony , Forget François , Turbet Martin , Millour Ehouarn
Published: July 2021

The climate of Mars during its first billion years is one of the most intriguing question in our understanding of the Solar System. The planet was host of a large amount of liquid water flowing on the surface throughout the Noachian era, approximatively 4Gya. Geomorphological observations is the main evidence for liquid water since valley networks and lakes are still visible on the surface, although dry nowadays.Different studies have tried to reproduce the conditions that may have occured on the planet, trying to find an atmospheric process or composition that could solve the Faint Young Sun Paradox. Theses modeling studies, through the use of 3-dimensional Global Climate Models struggled to warm sufficiently the past climate of Mars, even considering different greenhouse gases, the role of clouds, meteoritic impact or even volcanism (XXX). However, the presence of H2 could be an interesting solution for a sustainable warming as some recent studies suggest (Turbet and Forget, 2021). Another recent study (Ito et al. 2020) suggested that H2O2 might be a convincing candidate but has to be in high supersaturation ratio in the atmosphere, even though it only used a simplified 1D model and relatively high supersaturation levels.We try here to explore more in detail the scenario of supersaturated H2O2 and H2O, that also might be a specy able to provide a sufficient global warming under supersaturated conditions or through the formation of high altitude clouds. Since H2O is the major source of H2O2 in the atmosphere, it is important to assess whether the H2O content in the atmosphere is enough to provide high quantities of H2O2. We also try to constrain the theoritical supersaturation level of H2O/H2O2 that will allow the warming of the climate above 273K, but with a detailled 3D GCM simulation. Even if we do not tackle the question whether the supersaturation hypothesis is realistic or not, these results give a better understanding of  what would be Early Mars' climate under such conditions.
MAVEN Observations of Mini-Magnetosphere Dynamics within the Dayside Ionosphere of Mars
Authors: Bowers Charlie , Slavin James , DiBracccio Gina , Harada Yuki , Xu Shaosui
Published: July 2021

At Mars, the conductive ionosphere and localized, crustal magnetic anomalies interact with the upstream solar wind creating a unique, hybrid magnetosphere. As the interplanetary magnetic field (IMF) lines encounter the planet, the nature of their interaction with the magnetosphere will vary depending on whether they encounter regions in which crustal anomalies are absent, primarily in the northern hemisphere, or regions of strong (100-1000 nT at the surface) crustal magnetic fields, primarily in the southern hemisphere. Around regions of weak crustal magnetic fields, the IMF first encounters the conducting ionosphere of Mars and drapes around the obstacle analogous to the dayside of planets without global intrinsic magnetosphere. Around regions of strong crustal fields, the magnetic anomalies protrude out into space and create a “mini-magnetospheric” interaction between the draped IMF and the crustal anomalies analogous to the dayside of planets with a global intrinsic dipole field. Previous studies at Mars using both the Mars Global Surveyor (MGS) and Mars Atmosphere and Volatile EvolutioN (MAVEN) observations have found evidence of complex dynamics within these mini-magnetospheres within the dayside ionosphere, including current sheets, and magnetic flux ropes. Both these phenomena play a role in plasma transport and acceleration within the ionosphere and are associated with magnetic reconnection, which implicates a variety of dynamic process in planetary magnetospheres. In this study, we focus a single crustal anomaly region (CF1) in the northern Martian magnetosphere (~185°-215° longitude, ~5°-30° latitude (Figure 1)). Despite the magnetic moment of this anomaly being roughly 9 times weaker than those of strongest anomalies at Mars, it still shows evidence for dynamic interactions between the anomaly and the draped IMF. Here, we present analysis of current sheets and magnetic flux ropes found directly downstream from CF1 using magnetic field data taken by the magnetometer (MAG) instrument on board MAVEN. We also use data from the Solar Wind Electron Analyzer instrument to estimate magnetic topology, known as the topology score. This parameter distinguishes among 7 magnetic topologies and allows us to analyze the magnetic connectivity of the lobes of the current sheets and the likely formation mechanism of the flux ropes.Limiting our search to regions where MAVEN was on the dayside sampling at low altitude (
Searching for 3D effects in the optical, high spectral resolution emission spectrum of KELT-9b
Authors: Pino Lorenzo , Brogi Matteo , Désert Jean-Michel , Rauscher Emily
Published: July 2021

Ultra-hot Jupiters (UHJs; Teq ≥ 2500 K) are the hottest gaseous giants known. They emerged as ideal laboratories to test theories of atmospheric structure and its link to planet formation. Indeed, because of their high temperatures, (1) they likely host atmospheres in chemical equilibrium and (2) clouds do not form in their day-side. Their continuum, which can be measured with space-facilities, can be mostly attributed to H- opacity, an indicator of metallicity. From the ground, the high spectral resolution emission spectra of UHJs contains thousands of lines of refractory (Fe, Ti, TiO, …) and volatile species (OH, CO, …), whose combined atmospheric abundances could track planet formation history in a unique way. In this talk, we take a deeper look to the optical emission spectrum of KELT-9b covering planetary phases 0.25 - 0.75 (i.e. between secondary eclipse and quadrature), and search for the effect of atmospheric dynamics and three-dimensionality of the planet atmosphere on the resolved line profiles, in the context of a consolidated statistical framework. We discuss the suitability of the traditionally adopted 1D models to interprete phase-resolved observations of ultra-hot Jupiters, and the potential of this kind of observations to probe their 3D atmospheric structure and dynamics. Ultimately, understanding which factors affect the line-shape in UHJs will also lead to more accurate and more precise abundance measurements, opening a new window on exoplanet formation and evolution.
Systematics and Consequences of Comet Nucleus Outgassing Torques
Authors: Jewitt David
Published: July 2021

Anisotropic outgassing from comets  exerts a torque sufficient to rapidly change the angular momentum of the nucleus, potentially leading to rotational instability.  Here, we use empirical measures of  spin changes in a sample of comets to characterize the torques and to compare them with expectations from a simple model. Both the data and the model show that the characteristic spin-up timescale, τ, is a strong function of nucleus radius, r.    Empirically, we find that the timescale  varies as τ ~ 100 r2, where r is expressed in kilometers and τ is in years.  The  fraction of the nucleus surface that is active varies as fA ~ 0.1/r2, giving fA = 1 at r = 0.3 km.   We find that the dimensionless moment arm of the torque is widely scattered, with a median value $k_T$ = 0.004 (i.e. about 0.4% of the escaping momentum torques the nucleus), and weak (
Spectroscopic study of North West Africa 12269, a recently classified Martian meteorite.
Authors: Manzari Paola , Tempesta Gioacchino , Agrosì Giovanna
Published: July 2021

In this work we introduce a study of the North West Africa 12269 shergottite, recently discovered, using minimal and non-destructive analyses. A first chemical characterization will be performed by means of m-LIBS of an NWA 12269 sample.  Micro-LIBS measurements of this and other Martian samples could be useful for supporting the interpretation of analyses coming from LIBS instruments onboard the rover Curiosity and Perseverance.  
Billion-year trends in the aridity of river-forming climates on Mars
Authors: Kite Edwin
Published: July 2021

Summary. We analyzed a global database of constraints on Mars paleolake size relative to topographic catchment area (aridity index) and found evidence for climate zonation during the late-stage river-forming climates. Aridity increased over time in southern midlatitudes, but wetter climates (semiarid to arid) persisted near the equator and in the northern midlatitudes. 1. Introduction. Mars’ geology records multiple eras of precipitation-fed water runoff (e.g. [1,2]). Regionally integrated Valley Networks (VNs) formed early, ~3.6 Ga. Later, river-forming climates created deltas and alluvial fans up to 1.1 km thick [3,4]. This late-stage river-forming era consisted of multiple, intermittent, river-forming climates [5]. Within craters, most of the fluvial sediment transport was driven by runoff from crater sidewalls. Crater-lake levels could also have been maintained by water conveyed from crater sidewalls (by overland flow or shallow groundwater flow) or alternatively, by deep sourced groundwater sourced from rain/melt recharge at ~102-103-km scales.2. Results. To constrain late-stage river-forming climates, we carried out a global survey within large, young impact craters (n = 212; from [6]) for geologic constraints on crater lake size (i.e., aridity index) and lifetime. Survey results (Figs. 1-4) disfavor the hypothesis that late-stage lakes were caused by individually brief (
 The instruments at Telescopio Nazionale Galileo as resources for a broad community
Authors: Poretti Ennio
Published: July 2021

Four instruments mounted at the Telescopio Nazionale Galileo (Roque de Los Muchachos Observatory, La Palma) are currently used to study exoplanets.  They are HARPS-N and GIANO-B, also combined in the new GIARPS configuration, Dolores and Nics. They exploit both the visible and near-infrared domains. I present the scientific highlights obtained in the last years by different teams, since  the access to the TNG is open to the international community through distinct calls. 
BepiColombo – Mercury Swing-Bys
Authors: Zender Joe , Benkhoff Johannes , Murakami Go , Montagnon Elsa
Published: July 2021

AbstractThe BepiColombo spacecraft was launched on 20 October 2018 from the European spaceport in French Guyana and is currently on its way to Mercury. On its way, the spacecraft will swing-by Mercury six times in its stacked configuration, before releasing the Mercury Magnetospheric Orbiter (MMO) and the Mercury Planetary Orbiter (MPO) in their corresponding orbits around the target planet.IntroductionMercury is in many ways a very different planet from what we were expecting. On 20 October 2018 the BepiColombo spacecraft [1] started its 7 year journey to the innermost terrestrial planet to investigate on the fundamental questions about its evolution, composition, interior, magnetosphere, and exosphere.BepiColombo is a joint project between the Euro- pean Space Agency (ESA) and the Japanese Aero- space Exploration Agency (JAXA). The Mission con- sists of two orbiters, the Mercury Planetary Orbiter (MPO) and the Mercury Magnetospheric Orbiter (MMO). From their dedicated orbits the two space- craft will be studying the planet and its environment.The mission has been named in honor of Giuseppe (Bepi) Colombo (1920–1984), who was a brilliant Italian mathematician, who made many significant contributions to planetary research and celestial mechanics.During the cruise phase, the spacecraft flies in a stacked configuration: the MMO and MPO are mounted ontop of the Mercury Transfer Module (MTM). As a consequence, most remote sensing instruments onboard the MPO are mounted towards the MTM and have a fully obstructed field-of-view. The MMO instrumentation is shielded by a protection shield (MOSIF) and several instruments still await the deployment on measurement booms.Despite the reduced instrument availability, scientific and engineering operations will be scheduled during the cruise phase, especially during the swing-bys.Mercury Swing-bysFollowing the Earth and two Venus swing-bys, six Mercury swing-bys are foreseen from October 2021 until 9 January 2025. The poster will discuss the flyby geometries and potential operation opportunities, in comparison with the three MESSENGER Mercury swing-bys from 2008 and 2009 [2][3].References: [1] Benkhoff, J., et al. (2010) Planet. Space Sci. 58, 2-20. [2] Baker, D.N. et al. (2011) Planet. Space Sci 59, 2066-2074. [3] McNutt, R.L. et al. (2010), Acta Astronautica V67, Iss 7-8, p 681-687
Contributions of impact mixing to the spatial distribution of water ice in permanently shadowed lunar south polar complex craters: Haworth, Shoemaker, and Faustini
Authors: Montalvo Pedro E. , Hirabayashi Masatoshi , King Jr. David T.
Published: July 2021

Introduction: Lunar south polar permanently shadowed regions (PSRs) are known to host water ice [e.g., 1-6]. Moreover, water ice may be widely distributed in micro cold traps [7]. Lunar water transport processes include material mixing [13,14,17] and thermal processes [e.g., 8,9], which leads them to thermally stable regions [e.g., 10-12]. Because PSRs temperatures
Global variations in the vertical distribution of water during Mars Year 34 from multiple spacecraft observations
Authors: Holmes James , Lewis Stephen , Patel Manish , Aoki Shohei , Liuzzi Giuliano , Villanueva Geronimo , Crismani Matteo , Fedorova Anna , Alday Juan , Kass David , Vandaele Ann Carine , Korablev Oleg
Published: July 2021

Observations of the vertical distribution of water vapour provide a unique snapshot of the vertical transport processes that contribute to the global martian hydrological cycle. While previous datasets have largely been seasonally and spatially sparse, vertical profiles of water retrieved from the Nadir and Occultation for MArs Discovery (NOMAD) and Atmospheric Chemistry Suite (ACS) instruments on the ExoMars Trace Gas Orbiter (TGO) provide the most complete dataset so far. These data are now capable of providing robust constraints on the 4-D distribution of water, especially when also combined with retrievals of additional atmospheric properties (e.g. temperature profiles, dust column) that exert an influence on the evolving global water distribution.  

A key limitation though is the fact that observations of water profiles are still relatively limited in coverage, in the global sense, and the vertical distribution of water at latitudes and times not regularly probed by NOMAD and ACS remains poorly understood.   

To address this, we have created a global reference climatology of water vertical distribution for Mars Year (MY) 34 through a multi-spacecraft data assimilation combining several retrieval datasets with a Mars Global Circulation Model. Retrievals of dust column and temperature profiles from Mars Climate Sounder on the Mars Reconnaissance Orbiter and water vapour and temperature profiles from multiple instruments on the ExoMars TGO during the primary science phase covering the latter half of MY34 are combined through assimilation to create one unified physically consistent global dataset. 

The vertical water vapour distribution is investigated globally. During the initial coverage of TGO observation that covers the dusty season in MY34, northern polar latitudes are largely absent of water vapour below 20 km with variations in abundance above this altitude throughout the dusty season linked to transport from mid-latitudes during a global dust storm, perihelion season and the intense MY34 C storm. The atmosphere is in a supersaturated state above 60 km for most of the time period investigated, with lower altitudes showing more diurnal variation in the saturation state of the atmosphere. A key benefit of the data assimilation technique is that constraints on dynamical transport imposed by the assimilated water vapour and temperature profiles leads to improvements in the simulated water ice distribution even though it is not altered directly by the assimilation process. 

The climatology created, which will become publicly available for wider use by the martian scientific community, has also been independently validated against water vapour profiles from the SPICAM instrument. 