bluuebunny/crossref_metadata_2025 huggingface dataset:
Diurnal cycle of the Venus near-surface dynamics
Authors: Lefèvre Maxence
Published: July 2021

. IntroductionBelow 10 km the atmosphere of Venus virtually unknown, only the VeGa-2 has successfully measure the temperature in that region. At the surface, only Venera 9 and 10 directly measured the wind for respectively 49 min and 90 s, and several other probes like Venera 13 and 14 measured indirectly the wind speed. The amplitude of the measured wind speed is inferior to 2 m/s [4]. The planetary boundary layer has been studied with a global circulation model (GCM) [5], exhibiting a strong effect of the solar heating on the amplitude of the slope wind in the tropics. Additional studies are needed for the understanding of the near-surface dynamics and future landing missions. We propose to use a mesoscale model to study this part of the atmosphere.2. ModelTo study the near-surface dynamics, the LMD Venus mesoscale model [1] is used, composed of the Weather-Research Forecast (WRF) non-hydrostatic dynamical core [2] coupled with the IPSL Venus GCM physics package [3]. The domain is centered on Ovda Regio in Aphrodite Terra with a resolution of 20 km (Fig 1). The mesoscale boundary conditions are forced with the IPSL Venus GCM.Figure 1: Topography (km) of the mesoscale model, centered on Ovda Regio in Aphrodite Terra with a resoltion of 20 km.3. ResultsFig 2 shows the diurnal variation at the specific point for the zonal (blue) and meridional (red) winds, exhibiting a wind direction around noon. The amplitudes of the winds are consistent with in-situ measurements. The surface heat flux reaches a maximum value of 93 W/m 2 at noon. The surface temperature exhibits a diurnal cycle inferior at 2 K. Additional results about the near surface of Venus will be presented.Figure 2: Diurnal variation of the zonal wind (blue) meridional wind (red), surface heat flux (green) and surface temperature (black) for at the black dot in Fig 1.References[1] Lefèvre et al., Icarus, 335, 113376, 2020.[2] Skamarock, W. C. and J. B. Klemp, J., Comput. Phys., 227, 3465-3485, 2008[3] Garate-Lopez, I. and Lebonnois., S., Icarus, 314,1-11, 2018.[4] Lorenz, R., Icarus, 264, 311-315, 2016.[5] Lebonnois, S. et al., Icarus, 314, 149-158, 2018.
ExoClock project: a pro-am collaboration to monitor the exoplanet ephemerides for the Ariel space mission
Authors: Kokori Anastasia
Published: July 2021

ExoClock (exoclock.space) is a project aiming to monitor transiting exoplanets through regular observations using small and medium scale telescopes. The project is part of the ephemerides working group of ESA's Ariel space mission and the main scope is to maximise the mission efficiency. This effort was launched in EPSC2019 and we are actively collaborating with both professional and amateur astronomers coming from various countries across the world. In this talk, the current status of the project and the results of the first two publications will be presented. Our research includes a collective analysis of 1600 light-curves out of which 65% were obtained by amateur astronomers. This data was used to update the ephemerides of 180 planets. The ExoClock network currently consists of 270 participants out of whom 220 are amateur astronomers, a number that highlights the significant contribution of amateurs in our project. 
Dust Telescopes for Dust Astronomy
Authors: Srama Ralf , Sternovsky Zoltan , Kempf Sascha , Horanyi Mihaly , Postberg Frank , Krüger Harald , Kobayashi Masanori , Sterken Veerle
Published: July 2021

Dust Astronomy investigates the nature and the origin of dust particles in space. The particle size distribution ranges from nanodust to approximately 100 micrometer. The study of the elemental and/or chemical composition of the particles together with the knowledge about their origin provides insights into many disciplines. Dust Astronomy is an interdisciplinary working field, which includes Solar System Science, Interstellar Medium studies and Astrobiology. A basic tool for these studies are Dust Telescopes.Dust Telescopes are in-situ instruments to characterize individual dust particles by their velocity vector, size and composition. They are based on impact ionization used for time-of-flight compositional analysis and on charge induction for particle speed and size measurements. In this sense, already the Cassini Cosmic Dust Analyzer (CDA) was a simple Dust Telescope, which successfully characterized the dust environment at Saturn. Now, future missions go even further. In the next years the missions DESTINY+, EUROPA and IMAP will launch. In this talk, a summary is given about the capabilities of Dust Telescopes with a focus on the DESTINY+ Dust Analyser (DDA). DDA is a medium size instrument with a target diameter of 26 cm. A two-axis articulation allows to track dust RAM directions. Larger Telescopes like the record breaking LAMA instrument, developed especially for the measurement of low interstellar dust fluxes, and the instruments for the probes IMAP and EUROPA are compared with DDA.The paper will address questions about the detection of nanodust or, what is a good instrument approach for a Dust Observatory? What are the instrumental challenges for an Interstellar Probe?
Cloud-convection feedback in brown dwarfs atmosphere
Authors: Lefèvre Maxence , Tan Xianyu , Lee Elspeth , Pierrehumbert Raymond
Published: July 2021

. IntroductionBrown dwarfs are object between giant planets and star in term of mass, numerous observations suggest active meteorology. A near-infrared brightness variability is observed among L and T dwarfs. Several atmospheric dynamics have been proposed, but the mechanisms remain unclear. Clouds could also play an important role in shaping the thermal structure and spectral properties of these atmospheres via their opacity. In this study we propose to use a 3D convection resolving model couple to a grey-band radiative transfer and to a microphysical to study radiative cloud feedback over a large set of temperature, cloud composition and metallicity. The mechanism discussed in this study could play a role in the observed flux variability in brown dwarfs and is also applicable for directly imaged extrasolar giant planets.2. ModelTo study these mechanisms, the 3D non-hydrostatic dynamical CM1 is used coupled to a grey band radiative transfer [1]. An idealized cloud microphysical model was added, considering MgSiO3 , Fe, Al2O3 , CaTiO3 , Cr and MnS particles [3, 4, 5]. Particle settling is included. The effect of metallicity is taken into account. The clouds are radiatively active using Rosseland mean opacities. The cloud particles are considered spherical following a gaussian size distribution, with radius between 0.01 and 100 μm. The density of cloud particle is a free parameter. The model is initialized using temperature profile from a 1D model [2].Figure 1: Initial vertical temperature profile (solid line) and condensation profile for the considered clouds (dotted line).3. ResultsThe model shows that the convective layer height increases in function of the temperature (Fig 2). An estimate of the vertical mixing is determined. With the inclusion of radiative property of the clouds, some feedback is observed. MgSiO3 , Fe and Al2O3 clouds tend to expend the convective layer altitude. This feedback is most visible at high temperature and depends on the clouds particle size. CaTiO3 , Cr and MnS have very low impact on the convective layer, due to a thin cloud layer and a low abundance.Figure 2: Vertical profile of the mean potential temperature (K) for the different temperature cases considerate without clouds.References[1] Freedman, R. S., et al. The Astrophysical Journal SupplementSeries, 214(2):25. 2014.[2] Tan, X. and Showman, A. P. The Astrophysical Journal, 874(2):111. 2019.[3] Visscher, C., et al. The Astrophysical Journal, 716(2):1060–1075. 2010.[4] Wakeford, H. R., et al. Monthly Notices of the Royal Astronomical Society, 464(4):4247–4254. 2014.[5] Morley, C. V., et al. The Astrophysical Journal, 756(2):172. 2012.
A large meteoritic event over Antarctica ca. 430 ka ago inferred from chondritic spherules from the Sør Rondane Mountains.
Authors: Van Ginneken Matthias , Goderis Steven , Artemieva Natalia , Debaille Vinciane , Decrée Sophie , Harvey Ralph , Huwig Katherine , Hecht Lutz , Yang Shuying , Kaufmann Felix , Soens Bastien , Humayun Munir , Van Maldeghem Flore , Genge Matthew , Claeys Philippe
Published: July 2021

Introduction: Impactors several tens up to 200 m in size are likely to suffer complete disruption and to produce large airbursts, similarly to the Tunguska event over Russia in 1908 [e.g., 1]. Observations and numerical modeling of medium sized impacts producing large airbursts have shown that such impacts represent an important fraction of extraterrestrial matter accretion to Earth, with Tunguska-like events occurring every 100 to 10,000 years, which is notably more frequent than crater-forming impact events. However, little is known about occurrences of such airburst events in the geological record, principally because of the lack of readily identifiable evidences such as impact craters. Finding residues of such events is thus critical for assessing the complete impact history of the Earth. Here we present the discovery of extraterrestrial particles in the Sør Rondane Mountains, Queen Maud Land, Antarctica, which were produced during a “touchdown” impact event ca. 430 ka ago, when a large airburst vapor jet interacted with the Antarctic ice sheet.Material and Methods: Twenty nine igneous particles were recovered from glacial sediment collected during the 2017-2018 BELAM (Belgian Antarctic Meteorites) expedition that took place in the Sør Rondane Mountains, Queen Maud Land, Antarctica. Glacial sediment was sampled from a flat eroded summit in the Walnumfjellet (WN) area. 10Be exposure age of nearby summits suggest that the first sampled area has been continuously exposed over the last 870 ka [2]. About half the particles are compound spherules consisting of two or more spherules fused together. The petrography and mineralogy of 18 particles were determined at the Royal Belgian Institute of Natural Sciences of Brussels, Belgium. Their major and trace element compositions were determined at the Museum für Naturkunde of Berlin, Germany, and at Florida State University, USA, respectively. Oxygen isotopic compositions were determined by means of secondary ion mass spectrometry at the CRPG of Nancy, France.Results: The mineralogy of the particles consists of olivine and spinel, with minor interstitial glass. On the basis on their internal textures and spinel content, we identify four groups of particles: 1/ the spinel-rich particles (SR; N = 9; ≥19% vol. spinel); 2/ Porphyritic olivine (PO; N = 5;
Ganymede’s interaction with the jovian plasma from hybrid simulation
Authors: Modolo Ronan , Baskevitch Claire , Leblanc Francois , Masters Adam
Published: July 2021

The JUICE (JUpiter ICy moon Explorer) mission, selected by the European Space Agency in May 2012 to be the first large mission within the Cosmic Vision Program 2015–2025, will provide the most comprehensive exploration to date of the Jovian system in all its complexity, with particular emphasis on Ganymede as a planetary body and potential habitat (JUICE Red Book, 2014). The Galilean satellites are known to have thin atmospheres, technically exospheres (McGrath et al., 2004), produced by ion-induced sputtering and sublimation of the surface materials. These moons and tenuous atmosphere are embedded in the flowing plasma of the jovian. The interaction between the neutral environments of the Galilean satellites and the jovian plasma changes the plasma momentum, the temperature and generates strong electrical currents. In order to prepare the scientific return of the mission and the optimization of operation modes of plasma instruments, a modeling effort has been carried out at LATMOS (PhD R. Allioux, IRAP, 2012; L. Leclercq, LATMOS, 2015; O. Apurva, LATMOS, 2017). A 3D parallel multi-species hybrid model (Latmos Hybrid Simulation, LatHyS) has been developed to model and characterize the plasma environment of Ganymede (Leclercq et al, 2016; Modolo et al, 2016) and a 3D parallel multi-species exospheric model (Exospheric Global Model, EGM) to pattern the dynamic of the neutral envelopes of Ganymede (Turc et al, 2014; Leblanc et al, 2017). The presentation will examine the global structure of the interaction with the jovian plasma, to describe the formation of Alfvén wings, and to emphasize the phenomena related to the multi-species nature of the plasma. The simulation model supports the preparation of the JUICE mission and its Ganymede phase by characterizing boundary crossings.
Compositional Variations of the Highly Eccentric Planet HD 80606b
Authors: Tsai Shang-Min , Steinrueck Maria , Parmentier Vivien , Lewis Nikole , Pierrehumbert Raymond
Published: July 2021

The hot Jupiter HD 80606b has an extremely eccentric orbit (e ~ 0.93). The stellar irradiation the planet received drastically increases by more than two orders of magnitude during the perihelion passage. The variation due to eccentric orbits provides unique opportunities to directly probe the dynamical, radiative, and chemical timescales. To understand the interplay between these processes, we set up a model framework to explore the atmospheric response. We first run three-dimensional general circulation models of HD 80606b using MITgcm [1] for various atmospheric metallicities and internal heat. Based on the hemispheric-averaged results from the GCM, we then time-step the 1D photochemical model VULCAN [2] along the orbits to investigate the compositional response in detail. The kinetics results show that efficient vertical mixing leads to deep quench levels of CO and CH4. Because of the depth of quench levels where the radiative timescale is long, the temperature variations have no effects on the quenching behavior. Instead, photolysis and the rapid heating in the upper stratosphere is the main driver of the time-dependent chemistry. We find a transient state of [CO]/[CH4] > 1 after the perihelion. Since the quenched abundances of CO and CH4 are independent of the orbital phase, the [CO]/[CH4] ratio can provide constraints on the metallicity and internal heat. In addition, we find a sequence of sulfur species initiated by the sudden thermal and photochemical forcing near perihelion, which can be potential signatures for the existence of sulfur on hot Jupiters.Figure 1. Dayside averaged temperature as a function of time relative to perihelion from the 3D general circulation model, assuming solar metallicity and Tint =100 K. The white dotted line indicates perihelion and the black dotted lines enclose the period where the planet is in synchronous rotation. Figure 2. The dayside-averaged CO mixing ratio as a function of time relative to perihelion (left), compared to the hypothetical scenario where the planet is fixed at each orbital location (right) to isolate the orbital effects. 
Update on the SBNAF Infrared Database
Authors: Szakáts Róbert , Kiss Csaba , Müller Thomas , Marton Gábor , Alí-Lagoa Victor , Farkas-Takács Anikó , Bányai Evelin
Published: July 2021

One of the goals of the Small Bodies: Near and Far (SBNAF) H2020 project was to create an easy-to-use database for thermal infrared observations of small bodies. We collected published thermal IR measurements for our selected samples of Solar System targets including data from large missions (e.g. catalogues based on Akari, IRAS and WISE observations) and also data from smaller scale and individual reductions (e.g. the Herschel Space Observatory measurements of near-Earth and main belt asteroids). The primary goal of this database is to help scientists working in the field of modeling the thermal emission of small bodies. However, the database has the option to include more data of Solar System small bodies which have been observed at thermal IR wavelengths from space or with ground-based instruments. The database is online and accessible since March 2019, see the details in Szakáts et al. (2020).Our database was used, e.g. to help determine the shape and spin properties of (208) Lacrimosa asteroid in the Koronis family, (Vokrouhlický et al., 2021), to model the thermophysical state of two Hilda asteroids (1162) Larissa and (1911) Schubart, (Chavez et al., 2021) and to model the thermal emission of large main belt asteroids (Ali-Lagoa et al., 2020).In a recent update we added 324 new flux densities for 23 resonant trans-Neptunian and scattered disk objects to the database from Farkas-Takács et al. 2020, and in total we have now 170461 records. For the currently available data, its sources and the distribution of data from observatories and missions see Table 1.Table 1. List  of  observatories/missions,  observatory  codes,  instruments,  filters,  possible  observing  modes,and the number of measurements with a specific instrument, in the present version of the Infrared Database. Except for WISE, there are no available positions for the low-Earth orbit missions, so they are referred to as geocentric (JPL code ‘500@399’)In an upcoming update we are planning to extend the database with WISE W2 data, Uranus and Neptune satellite data, with flux densities from Herschel serendipitous asteroid observations, and disk-integrated thermal data of the Moon (Müller et al., 2021).The WISE W2 data will bring shorter wavelength flux densities to the database for selected asteroids. During the processing special attention will be given to those small bodies, mainly NEAs, for which the reflected light can cause discrepancies when calculating the colour correction factor. A proper warning will be given in the public database for such objects after the update.With the Herschel serendipitous asteroid observations we will expand the number of flux densities by around 600 records.
Measurement of Titan’s surface permittivity with the DraGMet/DIEL sensor on Dragonfly
Authors: Le Gall Alice , Chatain Audrey , Lorenz Ralph D. , Hamelin Michel , Deprez Grégoire , Osiander Robert , Berthelier Jean-Jacques , Hassen-Khodja Rafik , Lebreton Jean-Pierre , Joly-Jehenne Tom , Vettier Ludovic , Carrasco Nathalie
Published: July 2021

Titan, Saturn’s biggest moon, is an ocean world, covered by organic materials and therefore one of the most promising astrobiological target in the Solar System, likely holding clues on the origin of life on Earth. That is why NASA has selected the Dragonfly mission to send in 2027 a rotorcraft lander to Titan and investigate its prebiotic chemistry and habitability. Making multiple flights (up to 24 in 2.5 years, starting in 2034), Dragonfly will explore a variety of locations, from the Shangri-La dune field to the rim of the young impact crater Selk (Lorenz et al., 2018), and therefore sample materials and determine surface properties in different geologic settings. The two permittivity probes - called DIEL- on board the Geophysical and Meteorological package (DraGMet) will be especially useful to characterize Dragonfly landing site environment. DIEL consist of 2 electrodes acting as self-impedance permittivity probes. They will be mounted on each skid of the Dragonfly rotorcraft and operate independently for sake of redundancy and safety. Their objective is to measure the complex ground permittivity at several low frequencies (
The first atmospheric characterisation of Wasp-15b with Gaussian Process modelling
Authors: Petit dit de la Roche Dominique , van den Ancker Mario , Miles Páez Paulo
Published: July 2021

Wasp-15 b is an inflated hot Jupiter orbiting a bright host star. Its low density and consequent large atmospheric scale height make it an excellent candidate for atmospheric characterization using transmission spectroscopy. In fact, it has previously been observed with the FORS2 spectrograph on the VLT, but large systematics have so far prevented this data from being used. Here, we show that Gaussian Process modelling can remove systematic noise features with amplitudes up to that of the transit signal, allowing us to achieve a precision comparable to later data without the systematics. We present the first transmission spectrum of the atmosphere of Wasp-15 b and compare it to theoretical spectra to discuss the implications.
Electric properties of Titan’s dusty ionosphere
Authors: Shebanits Oleg , Wahlund Jan-Erik , Perryman Rebecca , Waite Hunter , Dougherty Michele
Published: July 2021

Recent studies have shown that negatively charged dust dramatically alters the electric properties of plasmas, in particular planetary ionospheres. Utilizing Titan flybys from the entire Cassini mission and full plasma content of the moon’s ionosphere (electrons, positive ions and negative ions/dust grains) we derive the electric conductivities and currents, updating and extending previous results which did not include the charged dust and focused on a limited range of flybys.Compared to the previous estimates, using the full plasma content increases the Pedersen conductivities by a factor ~2 and Hall conductivities by a factor ~1.2. We identify dusty plasma as the reason for the sharp increase of Pedersen conductivity below 1000 km altitude reported previously. Using the full range of Titan flybys also reveals the conductivities on the dayside to be factor ~7-9 larger than on the nightside, owing to higher dayside plasma densities as well as generally heavier plasma species on the nightside.
Young craters of Mercury correlating with offset magnetic anomalies
Authors: Galluzzi Valentina , Oliveira Joana S. , Wright Jack , Rothery David A. , Hood Lon L.
Published: July 2021

In the last months of its mission, MESSENGER was able to obtain measurements at low altitude (< 120 km). This has made it possible to measure small magnetic field signals, probably of crustal origin (Johnson et al, 2015). Maps of the crust signatures at 40 km altitude were produced by Hood (2016) and Hood et al. (2018), showing that the strongest anomalies are about 9 nT in the Caloris basin. Some of the anomalies are associated with impact craters, and it has been demonstrated that this is not a coincidence (Hood et al., 2018). It is believed that these anomalies are the result of impactor materials rich in magnetic carriers (e.g., metallic iron) that were incorporated on the surface acquiring remanent magnetic fields during the cooling of the material. We analyzed whether the anomalies of the crustal field are related to geological characteristics by examining two Hermean craters in order to test this impactor hypothesis. Anomalies associated with Rustaveli and Stieglitz craters are slightly or totally asymmetric with respect to the crater center. The morphology and geological setting of these two fresh impact craters that still maintain a well-preserved ejecta blanket and visible secondary crater chains are investigated to constrain the overall impact dynamics. In both cases, slight asymmetries in the morphology and ejecta distribution show that the magnetic anomalies correlate well with the location of impact melt. Rustaveli is associated with a ~5 nT crustal magnetic anomaly centered close to the crater’s midpoint, although offset ~20 km east-southeast. This offset is somewhat consistent with the downrange direction implied by Rustaveli’s impact melt and crater chains distribution. For Stieglitz, an anomaly larger than 3 nT includes most of the ejecta melt locations towards southwest. The ejecta melt cluster to the north of the crater corresponds to an anomaly of ~5 nT, while the largest anomaly of ~7 nT is found further north and closely corresponds to the crater’s deepest chain. For both craters, the melt likely recorded the prevailing magnetic field of Mercury after quenching. Hence, both impactors brought magnetic carriers to the surface that could record the past magnetic field of Mercury. Acknowledgments: The authors gratefully acknowledge funding from the Italian Space Agency (ASI) under ASI-INAF agreement 2017-47-H.0 and the European Union’s Horizon 2020 research and innovation programme under grant agreement No. 776276.Hood, J. Geophys. Res. Planets 121, 2016;Hood et al., J. Geophys. Res. Planets 123, 2018;Johnson et al., Science 348, 2015.
Sign languages to unfold the Universe
Authors: Varano Stefania
Published: July 2021

Sign languages ​​arise from the need of communities of deaf people to communicate with each other and with others. Like all natural languages, they are tied to the traditions and cultures of the communities that invented and developed them. The sign language used in Italy is the Italian Sign Language, LIS.The strong iconicity of LIS is very interesting from the point of view of communication and didactics of astronomy, also for the hearing impaired. The signs used for astronomical concepts and objects often express the meaning and nature of what is represented, much more than a single word in the Italian language does.LIS is therefore effective not only for inclusive communication aimed at deaf people, but it can be effective for everyone, both in terms of equity and awareness of diversity and in terms of knowledge of astronomy and its link with culture and tradition.We will present a set of videos published on EduINAF, the outreach and education online magazine of the Italian National Isntitute for Astrophysics, in which the LIS is the main medium of the storytelling. Each video has subtitles, in order to make the LIS understandable for all.
Rotational properties of the retrograde object (468861) 2013 LU28
Authors: Morales Nicolas , Ortiz Jose Luis , Santos-Sanz Pablo , Vara Monica , Souami Damya
Published: July 2021

Trans-Neptunian Objects (TNOs) are thought to be among the least evolved Solar System objects, which retain information on the origin and evolution of the outer parts of it. They are located at far distances of the Sun, where the influence of our star is less dramatic than in the closer regions. Thus, these icy objects are extremely interesting bodies that hide plenty of information on the physical and dynamical processes thatshaped our Solar System.We only know a few retrograde TNOs so far (e.g. 2008 KV42 [1], 2011 KT19 [2], 2004 XR190). One of the few known retrograde objects listed in the MPC database as a scattered disk object is 2013 LU28, which has a high orbital eccentricity (e = 0.95), a large semimajor axis (a= 181 AU) and a very high inclination (i = 125.4º). This exotic object is also classified as an “extended centaur”, because its perihelion at 8.7 AU moves it into the centaur region.The physical properties of 2013 LU28, such as its rotational period and light curve amplitude, are unknown but can be revealed through photometry. With this aim, we observed this object during three observing runs on 2021 January and March using two telescopes, the 1.23 m telescope at Calar Alto Observatory in Almería, Spain and the 1.5 m telescope at Sierra Nevada Observatory in Granada, Spain. From these observations we derived the first determination of the rotational light curve of 2013LU28 from which we derived its rotational period and its peak-to-peak light curve amplitude. The obtained amplitude turned out to be higher than the average amplitude of most TNOs, which points toward an elongated or a binary object. Other magnitudes, such as its absolute magnitude (H) were also derived. We will present and discuss preliminary results on all the above.AcknowledgementsThe authors acknowledge financial support from the State Agency for Research of the Spanish MCIU through the "Center of Excellence Severo Ochoa" award to the Instituto de Astrofísica de Andalucía (SEV-2017-0709). P.S-S. acknowledges financial support by the Spanish grant AYA-    RTI2018-098657-J-I00 "LEO-SBNAF" (MCIU/AEI/FEDER, UE). We are grateful to the CAHA and OSN staffs. This research is partially based on observations collected at the Centro Astronómico Hispano Alemán (CAHA) at Calar Alto, operated jointly by Junta de Andalucı́a and Consejo Superior de Investigaciones Cientı́ficas (IAA-CSIC). This research was also partially based on observation carried out at the Observatorio de Sierra Nevada  (OSN) operated by Instituto de Astrofı́sica de Andalucı́a (CSIC).Bibliography[1] B. Gladman, J. Kavelaars, J.-M. Petit, M. L. N. Ashby, J. Parker, J. et al. ApJ 697:L91–L94, 2009[2] Ying-Tung Chen , Hsing Wen Lin, Matthew J. Holman, Matthew J. Payne et al. ApJ 827:L24 (5pp), 2
Aqueous chemistry in the clouds of Venus
Authors: Rimmer Paul
Published: July 2021

Droplet chemistry in the clouds of Venus may play a role in regulating the depletion of sulfur dioxide and water vapor in and above the clouds. The specific nature of this chemistry is unknown. In this talk, I present three different scenarios for aqueous chemistry in the cloud droplets:Hydroxide salts
Reduced sulfites
Iron sulfates
I will discuss the effects of these three different aqueous chemistries, some of which may be accessible via remote observation. The iron sulfate chemistry in particular provides a candidate for the unknown UV absorber.
Nadir retrieval of ice clouds and dust from NOMAD/UVIS on board Exomars TGO
Authors: Willame Yannick , Mason Jon , Vandaele Ann C. , Erwin Justin , Piccialli Arianna , Depiesse Cédric , Wolff Michael J. , Daerden Frank , Thomas Ian R. , Ristic Bojan , Patel Manish R. , Bellucci Giancarlo , Lopez-Moreno Jose-Juan
Published: July 2021

The NOMAD (“Nadir and Occultation for MArs Discovery”) spectrometer suite on board the ExoMars Trace Gas Orbiter (TGO) has been designed to investigate the composition of Mars' atmosphere using a suite of three spectrometers operating in the UV-visible and infrared. NOMAD is a spectrometer operating in ultraviolet (UV), visible and infrared (IR) wavelengths covering large parts of the 0.2-4.3 µm spectral range [1].The UV-visible “UVIS” instrument covers the spectral range from 200 to 650 nm and can perform solar occultation, nadir and limb observations [2]. The main purpose of UVIS is dedicated to the analysis and monitoring of ozone and aerosols such as dust and ice clouds.  In the present work we will present preliminary results of the aerosol retrieval in the UV recorded in nadir geometry: spatial and seasonal distribution of ice clouds and dust.
 
References[1] Vandaele et al. 2018. Space Sci. Rev.[2] Patel et al., 2017. Applied Optics.
 
Monte Carlo transmission line modelling of multilayer optical coatings for performance sensitivity of exoplanet spectroscopy
Authors: Thurairethinam Vinooja , Savini Giorgio
Published: July 2021

Multilayer optical coatings are widely used on the surface of optical components to enhance the transmittance of light in certain spectral regions while reducing it in other regions. Discrepancies between the measured and predicted spectral performance of optical components with such coatings can primarily be attributed to deposition errors and uncertainties in the refractive indices of the materials used for these coatings. Our simulation uses two-dimensional transmission line modelling to evaluate the transmittance of light at a given angle of incidence through multilayer coatings deposited on a substrate material. We perform a number of Monte Carlo simulations to obtain statistical information about the tolerance of the coating performance to systematic and random uncertainties in deposition thickness, refractive index and operating temperature. We present the posterior distributions of the deviations from the nominal performance that result from the propagation of each of these uncertainties for a number of hypothetical scenarios. We find that these uncertainties have the potential to cause significant differences between the designed and achieved performance. Our results indicate that the sensitivity of each layer to the various sources of uncertainties can vary on a case-by-case basis. With the aid of accurate manufacturing recipes and uncertainty amplitudes from commercial manufacturers, this simulation can provide a proficient tool to predict variations in the performance of multilayer optical coatings used in exoplanet spectroscopy.
Simulations of Lunar Dust interaction with exploration systems and instruments
Authors: Cipriani Fabrice , Piette François
Published: July 2021

Lunar Dust is representing both an engineering challenge for future exploration missions due to systems potential contamination (due to regolith mobilization during e.g. traverse phases, landings, scooping, astronauts EVAs..) and a scientific target for e.g. mineralogical and compositional analysis of the Lunar surface. Therefore predicting not only interactions with systems but also payloads landed at the lunar surface is an important part of future missions design. Strong partnerships and synergies between agencies and space industries are now allowing the preparation of new missions with challenging timescales, for a return to the Moon in the next couple of years. In this context, the analysis of re-analysis of some of the Apollo era data and other landed assets is of high interest to perform the calibration of predictive algorithms and simulations tools of regolith transport and interactions with systems.The present work is organized in two parts: in the first part, we present a modelling study of two experiments included in the Apollo Lunar Surface Experiment Package (ALSEP): the Lunar Ejecta and Meteoroids Experiment (LEAM), which experienced failures linked to thermal control and the Dust Detector Experiment (DDE) which could measure solar cells performance variations due to dust coverage.In the second part, we present simulation results for the contamination of the Imaging System accommodated on the PROSPECT experiment that will be embarked on the Luna 27 lander, due to land on the Moon in the next couple of years.We will discuss the quality of our predictions, the uncertainties inherent to the measurements, and the way forward in terms of better representation of lunar dust transport and interactions processes through models.
Vnir reflectance spectroscopyof Mercury like glasses
Authors: Bruschini Enrico , Carli Cristian , Morlok Andreas , Capaccioni Fabrizio , Stojic Aleksandra , Weber Iris , Reggli Christian , Klemme Stephan , Hiesinger Harald
Published: July 2021

Glassy materials have been recognized over Mars, Moon and many different meteorites (Farrand et al. 2016; Delano 1986; Varela & Kurat 2004). Planetary glasses result from impact events but they are also found as volcanic products (Farrand et al 2016). Morlock et al. (2017) and Morlok et al. (2021) investigated by means of different experimental techniques (bi-directional diffuse reflectance FTIR, in situ FTIR microscopy, Raman, EPMA and optical microscopy) a suite of synthetic samples with composition similar to those inferred for different Hermean terrains. Here we extended the study of the same materials to the VNIR region (bidirectional reflectance spectroscopy: 350 to 2500 nm). We analyzed 8 different samples with different chemical compositions, produced under different oxygen fugacity conditions We prepared eight granulometric classes between 0 and 250 μm, namely: 0-25; 25-63; 63-100; 100-125; 125-150; 150-180; 180-200 and 200-250 μm. The dominant feature in the VNIR region is due to the Fe absorption band at about 1 μm accompanied, in the more oxidized samples, by a smaller feature at 480 nm likely due to ferric oxide development. Iron free samples (FeO < 0.1 wt%) show characteristic spectral shapes with a distinctive feature at about 640 nm attributable to TiO2. Even for very low FeO content, it is possible to observe a weak yet clear band at about 900-1000 nm due to Fe absorption which explain the dominance of the spectral features due to Fe absorption at higher FeO content. Additional small bands at higher wavelengths (1300-1400 and 1900 nm) suggest a low content of water and/or –OH species in the samples. We investigated the spectral features as a function of composition, grain size and oxidation in order to gain as much information as possible on the nature of the spectra and compare them with remote sensing data or meteorites VNIR comparison. Our data on synthetic and realistic Hermean compositions will allow a better understanding of remotely acquired VisNIR spectra, which will be particularly helpful in view of the upcoming beginning of the BepiColombo ESA/JAXA mission. Acknowledgments: The authors acknowledge financial contribution from the Italian Space Agency (ASI) under ASI-INAF agreement 2017-47-H.0 (Simbio-SYS). CC, EB are also supported by agreement ASI-INAF n.2018-16-HH.0.
Global Mapping and Analysis of the Structural Features in the Northern Smooth Plains of Mercury
Authors: cardinale marco , Di Achille Gaetano , A.Vaz David
Published: July 2021

Orbital data from the Messenger spacecraft (1) reveal that part of the Mercury surface is covered by smooth plains, which are interpreted to be flood volcanic material across the planetary surface (2). In this work, we present a detailed geo-structural map of the northern smooth plains between  latitudes 29°N and 65°N. Our 1:100.000-scale map is obtained semi-automatically, using an algorithm to map all scarps from a DEM (3,4) followed by visual inspection and classification in ArcGIS. We created a DEM  using the raw MLA (Mercury Laser Altimeter) data (1) ,with 500 m/pix, and we used the Mercury Messenger MDIS (Mercury Dual Imaging System) (1,2) base map with 166m per pixel for the classification stage. With this approach, we mapped and characterized 51664 features on Mercury, creating a database with several morphometric attributes (e.g. length, azimuth, scarp height) which we will use to study the tectonic evolution of the smooth plains. In this way, we classified wrinkle ridges’s scarps, ghost craters, rim craters and central peaks. The morphometric parameters of the wrinkle ridges will  be quantitatively analyzed, in order to characterizer the possible tectonic process that could have formed them.This map can be considered an enhancement for the north pole of the global geological map of Mercury (1, 5). ReferencesHawkins, S. E., III, et al. (2007), The Mercury Dual Imaging System on the MESSENGER spacecraft, Space Sci. Rev., 131, 247–338.. 
Denevi, B. W., et al. (2013), The distribution and origin of smooth plains on Mercury, J. Geophys. Res. Planets, 118, 891–907, doi:10.1002/jgre.20075.
Alegre Vaz, D. (2011). Analysis of a Thaumasia Planum rift through automatic mapping and strain characterization of normal faults. Planetary and Space Science, 59(11-12), 1210–1221. doi:10.1016/j.pss.2010.07.008 .
Vaz, D. A., Spagnuolo, M. G., & Silvestro, S. (2014). Morphometric and geometric characterization of normal faults on Mars. Earth and Planetary Science Letters, 401, 83–94. doi:10.1016/j.epsl.2014.05.022.
Kinczyk, M. J., Prockter, L., Byrne, P., Denevi, B., Buczkowski, D., Ostrach, L., & Miller, E. (2019, September). The First Global Geological Map of Mercury. In EPSC-DPS Joint Meeting 2019 (Vol. 2019, pp. EPSC-DPS2019).
Effects of tidal heating in Proxima Centauri b's thermal evolution
Authors: Sanchis Enrique , Noack Lena
Published: July 2021

The recent discovery of a terrestrial planet orbiting Proxima Centauri, our closest neighbor (an M5.5V star of 0.1 MSun mass and only 1.3 pc distance to the Sun), offers an excellent planet laboratory to study the most important theories of planet evolution and composition. The planet (Proxima b) is orbiting the star in its habitable zone at a separation of only ~0.05 AU and an orbital period of ~11 days, and most recent studies suggest a non-zero eccentricity of about 0.17. With a mass of >=1.2 MEarth, Proxima b is expected to have a rocky composition, which might resemble the Earth. It is therefore an excellent target to characterize terrestrial planets similar to Earth, avoiding the inherent biases of only studying the terrestrial planets of the solar system.Due to its close orbit and expected eccentricity, Proxima b most likely suffers from severe tidal heating, which can have an extreme incidence in the planet's habitability and the survival of an atmosphere. In this work, we perform a comprehensive analysis of the incidence that different distribution patterns of tidal heating can have on Proxima b's interior and thermal evolution. To accomplish this goal, we consider various possible geometries of the planet, from the simplest case, homogeneous distribution of the generated heat, to the more complicated cases, with an inhomogeneous distribution pattern that depends on the planet's interior structure (a stratified sphere, an incompressible homogeneous planet, or a two-layer structure with a differentiated core). The different models considered alter how tidal heat is distributed throughout the planet's interior, which can highly affect its overall thermal evolution.Furthermore, due to its proximity to the central star, Proxima b may as well be in synchronous rotation with Proxima Centauri. This can cause an extreme surface temperature variation between the hemisphere that permanently faces the star and the opposite hemisphere. In this work, the effect that synchronous rotation may have on Proxima b's interior is also thoroughly investigated.
The high sensitivity accelerometer ISA during the BepiColombo spacecraft Earth flyby: data analysis, lessons learned, and expected signals for the next
Authors: Santoli Francesco , Fiorenza Emiliano , Lefevre Carlo , Lucchesi David Massimo , Lucente Marco , Magnafico Carmelo , Peron Roberto , De Filippis Umberto
Published: July 2021

ISA (Italian Spring Accelerometer) is a high sensitivity, relative, mass-spring accelerometer. It flies as scientific payload on-board  the Mercury Planetary Orbiter (MPO), module of BepiColombo ESA mission to Mercury. The accelerometer is sensitive to any acceleration, greater than 2*10-8 ms-2Hz-1/2, that changes  the spacecraft motion from a pure free fall: the, so called, Non Gravitational Perturbations (NGP). ISA data will be added, at Mercury, to the orbit determination estimation in order to help reconstructing the orbit and to make the MPO an a-posteriori free-fall satellite.After the first commissioning phase, performed in between November 2018 - August 2019, and that allowed to verify the functionality of the instrument itself, the first direct verification of the correct behaviour of the system was carried out during the BepiColombo Earth Flyby. Indeed,  the spacecraft crossed the planet Earth shadow during the flyby and the direct Solar Radiation Pressure (SRP), the main contribution of NGP accelerations, dropped suddenly, marking a clear leap (gap)  in the gathered data. The scientific team compared, on the base of the satellite surface exposition and radiative characteristics, the observed “drop” in the acceleration, once removed  the on-board disturbances and inertial accelerations due to spacecraft rotations. In the talk, other ISA data recorded during the Earth Flyby are reported and expected signals for the upcoming Venus#2 Flyby and Mercury #1 Flyby are presented.  
Site Identification and Sample Analysis with ExoMars Mission mock-up instruments on a Martian analogue site on Mt. Etna
Authors: de Palma Gaia , Ehreiser Anouk , Lakomiec Patrycja , Schlarmann Leander
Published: July 2021

The landing site of the ExoMars 2022 mission is Oxia Planum, a basin rich in hydrated minerals located between Mawrth and Ares Vallis. Its clay-rich deposits of Noachian age have been covered by volcanic outflows, that have only recently started to erode away. This makes it more likely that biochemical markers have been preserved as they were shielded from long-term cosmic ray exposure.Martian analogue sites are valuable testing-grounds for both instrumentation and scientific analysis. During the EuroMoonMars Etna campaign, mockups of ExoMars instruments were used to perform scientific analysis on a Martian Analogue site on Mt. Etna.Satellite images are used to identify sites of interest on the slopes of Mt. Etna, mimicking the use of images and data from the MRO CTX, HiRISE, MEX HRSC and the CRISM spectrometer, to characterise the surface of Oxia Planum during the ExoMars Mission.On the ground, Panoramic imaging and wide-angle photographs are used to select sites for close-up study with a mock-up of the Pancam instrument. Pancam is a set of two wide angle cameras for multi-spectral stereoscopic panoramic imaging, and a high resolution camera for colour imaging.On selected sites, geological and biogeochemical markers are identified and characterized using Raman spectroscopy and optical microscopy, mimicking ExoMars’ onboard instruments RLS (Raman Laser spectrometer), and CLUPI (Close-up imager).
Follow-Up Lightcurves Multitool Assisting Radial velocities (FULMAR)
Authors: Rodrigues José , Barros Susana , Santos Nuno
Published: July 2021

TESS is now routinely discovering new exoplanets and candidates (2647 TOIs in April 2021). Detailed analysis of the TESS lightcurves is necessary to select the best candidates for Radial Velocities (RV) follow-up as we cannot realistically observe all TOIs using ground facilities due to the instrument time required.We developed a modular tool called "Follow-Up Lightcurves Multitool Assisting Radial velocities (FULMAR)" to select suitable follow-up targets more effectively, as the ones with lower stellar activity would require fewer observations to be confirmed. Our code compiles available TESS lightcurves for any selected target. It can filter the activity using different methods, compute the rotation period of the star using Gaussian Processes, search for transits in the detrended lightcurve using BLS or TLS and probe signals that were detected with RV. FULMAR could also reduce the necessary observation time per target, for example by killing aliases, allowing for the characterization of more systems with a given instrument. 
Cassini CAPS-ELS Observations of Negative Ions in Titan's Ionosphere: Solar Zenith Angle - Density Trends
Authors: Wellbrock Anne , Coates Andrew , Jones Geraint , Haythornthwaite Richard , Shebanits Oleg , Vigren Erik , Lavvas Panayotis , Vuitton Véronique
Published: July 2021

The discovery of heavy organic anions by in situ measurements using Cassini’s CAPS Electron Spectrometer (ELS) in Titan’s ionosphere was an unexpected result of the Cassini mission (Coates et al, 2007, Waite et al, 2007); a complete reconsideration of chemical processes in this enigmatic atmosphere was necessary as a result. These negative ions can be associated with complex hydrocarbon and nitrile processes which are linked to haze formation at lower altitudes. Cassini’s CAPS ELS observed negative ions during Titan encounters at altitudes below 1400 km. The ions can reach masses over 13,000 amu/q (Coates et al., 2009), while recurring peaks in the mass spectra can be used to identify different mass groups as reported by Coates et al. (2007) and Wellbrock et al. (2013, 2019). Studying density and mass trends of these groups helps to identify controlling factors of the production and destruction mechanisms, and ultimately to improve our understanding of how organic macromolecules can be produced by naturally occurring abiotic processes. In this study we examine the effects different solar zenith angle conditions might have on both the light and heavy negative ion mass groups, and consider the role of processes such as photodetachment and dissociative electron attachment. We also compare the negative ion data with RPWS electron measurements and discuss the possible implications associated with the above processes.