bluuebunny/crossref_metadata_2025 huggingface dataset:
Investigating the Chemical Composition of the CIRS-Observed 160 cm-1 Ice Cloud in Titan’s Stratosphere
Authors: Ugelow Melissa , Anderson Carrie
Published: October 2020

Remote sensing observations from Voyager 1’s InfraRed Interferometer Spectrometer (IRIS) and Cassini’s Composite InfraRed Spectrometer (CIRS) confirmed the presence of nitrile ice clouds in Titan’s stratosphere (Samuelson 1985, 1992; Khanna, R.K. et al., 1987; Samuelson et al., 1997, 2007; Coustenis, A. et al., 1999; Mayo and Samuelson, 2005; Anderson, C.M. et al., 2010, 2018a,b; Anderson and Samuelson, 2011). While individual gases in Titan’s stratosphere are expected to condense to form pure ices, some of these gases will enter altitude regions where they undergo simultaneous saturation, or co-condensation, and form a mixed ice. The infrared spectral features resulting from a mixed ice have their own unique spectral signatures that notably diverge from the weighted sum of the individual species, and must therefore be experimentally determined as functions of temperature and mixing ratio (Anderson and Samuelson, 2011; Anderson et al. 2018a,b).The first observation of a co-condensate in Titan’s stratosphere was acquired by CIRS, which revealed a spectrally broad quasi-continuum ice emission feature with a spectral peak near 160 cm-1.  Based on the altitude of the observed cloud top, combined with preliminary experimental efforts (Anderson and Samuelson, 2011), the co-condensate was determined to predominately contain cyanoacetylene (HC3N) and hydrogen cyanide (HCN). Here we present experimentally-measured absorbance spectra for the far-, mid-, and near-IR spectral regions (1.25 – 200 µm; 8000 – 50 cm-1), along with the corresponding optical constants, of HC3N-HCN co-condensed ices utilizing the SPECtroscopy of Titan-Related ice AnaLogs (SPECTRAL) Chamber (Anderson et al., 2018a). Various deposition temperatures and mixing ratios of mixed HC3N and HCN were systematically studied to quantify the chemical composition of Titan’s CIRS-observed 160 cm-1 stratospheric ice cloud emission feature.
The Solar System Treks Mosaic Pipeline (SSTMP)
Authors: Curtis Aaron , Law Emily , Malhotra Shan , Day Brian , Trautman Marshall , Gallegos Natalie , Nainan Charles
Published: October 2020

Solar System Treks Mosaic Pipeline (SSTMP) is a new, open-source tool for generation of planetary DEM and orthoimage mosaics. Opportunistic stereo reconstruction from pre-existing orbital imagery has in the past typically required significant human input, particularly in the pair selection and spatial alignment steps. Previous stereo mosaics incorporate myriad human decisions, compromising the reproducibility of the process and complicating uncertainty analysis. Lack of a common framework for recording operator input has hindered the community's ability to collaborate and share experience to improve stereo reconstruction techniques. SSTMP provides a repeatable, turnkey, end-to-end solution for creating these products. The user requests mosaic generation for a bounding box or polygon, initiating a workflow which results in deliverable mosaics usable for site characterization, science, and public outreach.The inital release of SSTMP focuses on production of elevation and orthoimage mosaics using data from the Lunar Reconaissance Orbiter's Narrow Angle Camera (LRO NAC). SSTMP can automatically select viable stereo pairs, complete stereo reconstruction, refine alignments using data from the LRO's laser altimeter (LOLA), and combine the data to produce orthoimage, elevation, and color hillshade mosaics.SSTMP encapsulates the entire stereo mosaic production process into one workflow, managed by Argo Workflow opensource Kubernetes-based software. Each process runs in a container including all tools necessary for production and geospatial analysis of mosaics, ensuring a consistent computing environment. SSTMP automatically retrieves all necessary data. For processing steps, it leverages free and open-source software including Ames Stereo Pipeline, USGS ISIS, Geopandas, GDAL, and Orfeo toolbox.
The STUDIO UV astronomy mission: a step towards a european ballon observatory
Authors: Taheran Mahsa , Duffard René , Maier Philipp , Colin Angel , Pahler Andreas , Bougueroua Sarah , Conti Lauro , Mueller Thomas , Lockowandt Christian , Ortiz Jose Luis , Ångerman Maria , Hanke Lars , Janson Olle , Stelzer Beate
Published: October 2020

For most astronomical measurements, observations in the ultraviolet (UV) at wavelengths below ~320 nm are not possible from the ground because of atmospheric extinction by the atmosphere. Early on, observers started using stratospheric balloons as relatively flexible and affordable means to access ultraviolet wavelengths, thus overcoming most atmospheric limitations.

Balloons offer a flexible and affordable alternative to space telescopes, with short development times and comparably good observing conditions in many wavelength ranges. Yet, the entry burden to use balloon-borne telescopes is high, with research groups typically having to shoulder part of the infrastructure development as well. Aiming to ease access to balloon-based observations, we present the concept of a community-accessible balloon-based observatory, the European Stratospheric Balloon Observatory (ESBO). ESBO aims at complementing the current landscape of scientific ballooning activities by providing a service-centered infrastructure for broad astronomical use, performing regular flights and offering an operations concept that provides researchers with a similar proposal-based access to observation time as practiced on ground-based observatories.

The STUDIO (Stratospheric Ultraviolet Demonstrator ofan Imaging Observatory) mission consists of the development and construction of a versatile prototype gondola (figure 1) and telescope (figure 2), which shall perform technology tests as well as deliver first scientific results from astronomical observations during its maiden flight planned for 2021. Its main optical payload includes a 50 cm aperture telescope to the back of which the Telescope Instruments Platform (TIP) will be attached. STUDIO is the prototype mission and the first objective of the research infrastructure project ESBO DS.

Fig 1: Mechanical Gondola Structure
 

The TIP will include a primary instrument for the ultraviolet to cover a scientific wavelength interval from 180 nm to 330 nm, as well as visible instrument to cover a complementary spectrum up to 1000 nm.

 
Fig 2: Studio Telescope and Telescope Instrument platform
 
 

Two science cases motivate the UV scientific part of STUDIO, namely: (1) The observations of exoplanets hosting stars and (2) UV observations of planetary atmospheres
Technically the prototype will aim to:- Demonstrate the maturity of critical technologies (e.g. safe landing and recovery)
- Demonstrate a next-generation UV instrument on the prototype
- Ensure the availability of a prototype instrument for scientific use after the end of ESBO DS
Influence of some resonances on the inclination of a satellite
Authors: Vaillant Timothée , Correia Alexandre C. M.
Published: October 2020

Knowing if the inclination of a satellite with respect to the equator of its planet is primordial can give hints on its origin and its formation. However, several mechanisms are able to modify its inclination during its evolution. The orbit of a satellite evolves over time and because of the tidal dissipation its semi-major axis can notably decrease or increase. Therefore the satellite can encounter several resonances in which it can potentially be captured. Some resonances are able to modify the equatorial inclination of a satellite. Touma and Wisdom (1998) noted that a resonance called ‘eviction’ between the mean motion of the Earth and the ascending node frequency of the Moon could increase by several degrees the equatorial inclination of the early Moon and could explain the present orientation of its orbit. Yokoyama (2002) studied these resonances for Phobos and Triton and observed that several resonances of this type can increase the equatorial inclination of Phobos in the future. In this work, we study the different existing ‘eviction’ resonances to determine their possible influence on the equatorial inclination of a satellite. When a satellite goes through such a resonance, the capture is not certain and as noted by Yokoyama (2002), the probability of capture depends on several parameters as the obliquity of the planet and the interaction between other resonances. We consider the case of Phobos where we search to estimate the probability of a capture in an ‘eviction’ resonance by using an analytical Hamiltonian model and numerical simulations. This work will then notably estimate the probability that Phobos will be captured in the future in an ‘eviction’ resonance able to modify significantly its inclination and will measure the influence of the different parameters over the probability of capture. Acknowledgments: The authors acknowledge support from project POCI-01-0145-FEDER-029932 (PTDC/FIS-AST/29932/2017), funded by FEDER through COMPETE 2020 (POCI) and FCT. References: Touma J. and Wisdom J., Resonances in the Early Evolution of the Earth-Moon System. The Astronomical Journal, 115:1653–1663, 1998.Yokoyama T., Possible effects of secular resonances in Phobos and Triton. Planetary and Space Science, 50:63–77, 2002.
Impact of photochemical hazes on the thermal structure of exoplanet atmospheres
Authors: Lavvas Panayotis , Arfaux Anthony
Published: October 2020

Transit observations reveal that a significant population of the detected exoplanets has hazy atmospheres (Sing et al. 2016). Although the relative contribution of clouds and photochemical aerosols is not yet fully clarified, the impact of haze particles on the thermal structure could be significant, as such particles can efficiently scatter and absorb radiation over a large part of the electromagnetic spectrum. Particularly, photochemical aerosols are anticipated to be present at pressures lower than those of cloud formation. The transit observations of HD 189733 b indicate that the haze opacity responsible for the UV-Visible slope is located at pressures between 1μbar and 1 mbar. As such low pressures, the presence of hazes could allow for strong temperature inversions due to the low atmospheric density. We investigate here the implications of such hazes on the exoplanet atmospheric thermal structure.We simulate the atmospheric thermal structure using a 1D radiative-convective model. The model utilizes non-equilibrium chemical composition results (Lavvas et al. 2014) for the gas phase composition, and haze particle size distributions calculated from an aerosol microphysical growth model (Lavvas & Koskinen 2017, Lavvas et al. 2019). We do not yet consider the non-LTE effects for the gases, but we do take into account the impact of temperature disequilibrium between the particles and the gas envelope that can strongly affect the heating efficiency of the particles. We consider various gas phase opacities from atomic and molecular contributions calculated through correlated-k coefficients.Our results demonstrate that in the lower atmosphere the simulated temperature profiles provide emission spectra that are in good agreement with the eclipse observations for the simulated targets (HD 209458 b and HD 189733 b). In the upper atmosphere of the hazy HD 189733 b the simulated haze distribution, which fits the transit observations, results in a strong temperature inversion. On the contrary, the upper atmosphere of the clear HD 209458 b, is significantly colder compared to previous evaluations based on equilibrium chemistry assumption. The implications of these results on the chemical composition will be discussed, as well as results from other exoplanet cases. 
Keck Time-resolved Spectrophotometry of Temporarily-Captured Minimoon 2020 CD3
Authors: Bolin Bryce , Fremling Christoffer , Holt Timothy , Hankins Matthew , Anand Shreya , De Kishalay , Deshmukh Kunal , Kasliwal Mansi , Morbidelli Alessandro , Purdum Josiah , Quimby Robert
Published: October 2020

Keck Time-resolved Spectrophotometry of Temporarily-Captured Minimoon 2020 CD3
Bryce T. Bolin (1,2), Christoffer Fremling (1), Timothy R. Holt (3,4), Matthew J. Hankins (1), Shreya Anand (1), Kishalay De (1), Kunal Deshmukh (5), Mansi M. Kasliwal (1), Alessandro Morbidelli (6), Josiah Purdum(7), Robert Quimby (7,8)
(1) Division of Physics, Mathematics and Astronomy, Caltech, Pasadena, CA 91125, USA (bbolin@caltech.edu)
(2) IPAC, Mail Code 100-22, Caltech, 1200 E. California Blvd., Pasadena, CA 91125, USA
(3) Centre for Astrophysics, University of Southern Queensland, Queensland, Australia
(4) Southwest Research Institute, Department of Space Studies, Boulder, CO. USA.
(5) Dept. of Metallurgical Engineering and Materials Science, Indian Institute of Technology Bombay, Powai, Mumbai-400076, India
(6) Université Côte d’Azur, Observatoire de la Côte d’Azur, CNRS, Laboratoire Lagrange, Boulevard de l’Observatoire, CS 34229, F-06304 Nice cedex 4, France
(7) Dept. of Astronomy, San Diego State University, 5500 Campanile Dr, San Diego, CA 92182, U.S.A.
(8) Kavli Institute for the Physics and Mathematics of the Universe (WPI), The University of Tokyo Institutes for Advanced Study, The University of Tokyo, Kashiwa, Chiba 277-8583, Japan
We report on rotationally-averaged visible spectrophotometry of minimoon 2020 CD3, the second known asteroid to be temporarily gravitationally captured by the Earth-Moon system, taken with Keck I/LRIS  between 434 nm and 912 nm in B, g, V, R, I and RG850 bands as it was leaving the Earth-Moon system on 2020 March 23 UTC. We find that the broad-band spectrum of 2020 CD3 most closely resembles a V-type asteroid and some lunar rock samples with a reddish surface with a slope of 18 +/- 3 % between 434 nm and 761 nm corresponding to colors of g-r = 0.62 +/-0.08, r-i = 0.21 +/- 0.06 and an absorption band at ~900 nm corresponding to i-z = -0.54 +/- 0.10 (Isaacson et al. 2011, DeMeo & Carry 2013) as seen in the left panel of Fig. 1. Assuming typical albedos of V-type asteroids, we constrain 2020 CD3's size to be ~1.0 +/- 0.1 m in diameter when combined with our measured H magnitude of 31.74 +/- 0.14.  In our time-series data, we detect periodic lightcurve variations corresponding to a rotation period of ~573 s and a Lomb-Scargle false alarm probability of
Characterizing HDS209458b and HD189733b with combined High and Low Resolution Spectroscopy
Authors: Zalesky Joe , Line Michael , Brogi Matteo
Published: October 2020

High Resolution Cross Correlation Spectroscopy (HRCCS) has become a powerful tool to constrain both the physical characteristics and abundances of atomic/molecular constituents in exoplanetary atmospheres. Brogi & Line (2019) recently introduced a novel Bayesian atmospheric retrieval methodology that can combine observations from both longer wavelength (2-4 micron), ground-based, HRCCS and shorter wavelength (1-2 micron) space-based observatories such as the Hubble Space Telescope (HST). Here we present results from the application of this technique to both new and previously published observations of HD209458b and HD189733b from VLT/CRIRES, HST, and Spitzer. The more complete wavelength coverage provides a more comprehensive assessment of the atmosphere by way of stronger constraints on the thermal profiles, atmospheric metallicity, and carbon/oxygen inventory for these two benchmark planets. We also investigate the impact of possible model-induced biases including assumptions regarding molecular cross-sections, cloud model prescriptions, and thermal profile parameterizations. Finally, we present what constraints may be possible in the future by performing retrievals of synthetic observations from the next generation of high-resolution spectrographs like CRIRES+. This work has laid a foundational dataset that combines both space and ground-based observations to comprehensively characterize exoplanetary atmospheres and will be a useful benchmark in comparison to future efforts for both transiting and non-transiting atmospheric characterization.
NEOSM Survey Cadence and Simulation
Authors: Sonnett Sarah , Mainzer Amy , Grav Tommy , Spahr Tim , Lilly Eva , Masiero Joseph
Published: October 2020

The Near-Earth Object Surveillance Mission (NEOSM) is a planned space-based infrared mission that will nominally launch in 2025 and librate at the Earth-Sun L1 Lagrange point.  The NEOSM Project was formulated to address the need to detect, catalog, and characterize near-Earth objects (NEOs) to support informed decision making for any potential mitigation activity. NEOSM detects NEOs, obtains high quality orbits for them, provides physical characterization of the NEOs and their source populations, and provides more detailed physical characterization for individual targets with significant impact probabilities.  Specifically, NEOSM will detect, track, and characterize 2/3 of potentially hazardous asteroids (PHAs) larger than 140m - large enough to cause potentially significant regional damage.  NEOSM is expected to detect thousands of comets, hundreds of thousands of NEOs and millions of main belt asteroids. Since moving objects, in particular NEOs, are the main focus of the NEOSM project, the survey can be optimized for maximum discovery rate by adjusting the survey cadence to ensure efficient and reliable linking observations into tracklets, which are position-time sets of a minor planet. It is also important for the survey cadence to provide self-followup that yields orbits with quality similar to that of the known NEOs today. The NEOSM Investigation Software Suite (NISS) is a set of tools being developed to support the efforts to optimize the survey and verify the ability of the designed mission to meet its scientific objectives. The NISS consists of a comprehensive representation of the mission performance, including the flight system hardware, mission operations, and ground data system processing. The NSS takes as its input a reference population of solar system bodies, the NEOSM Reference Small Body Population Model (RSBPM), and performs a frame-by-frame simulation of the survey over the course of its entire operational lifetime. Note that the RSBPM allows for performance to be evaluated as a function of diameter, rather than the traditional method of equating absolute magnitude H = 22 mag as a proxy for 140m. It has been shown that a completeness of 90% of objects with H < 23 mag is needed in order to ensure that 90% of objects larger than 140 m are found. We present here our ongoing work on mission architecture trades and the optimization of the survey cadence for NEO discovery and tracking. We will present the latest NEOSM survey cadence and its expected performance.  We will present the completeness rate after the baseline 5-year mission and a possible extended mission.  Studies have previously shown that the 90% goal can be achieved by a combination of a space mission like NEOCam and a ground based survey like LSST. We will also present how the survey cadence provides self-followup of the NEOs population and ensures orbital quality on par with the current NEO population.
Investigating the Dynamics of Hothouse Earth Climates with a Simplified GCM
Authors: McKinney Matthew , Mitchell Jonathan
Published: October 2020

There are records of past Earth climates that were ice-free all the way to the poles (Barron 1983), which can be described as “hothouse” climates. These hothouse climates can be contrasted with an “all-tropics” planet, where the tropics are defined by the atmospheric dynamics, i.e. the Hadley Cell extent (Faulk et al. 2017). This classification is thus primarily dependent on a planet’s rotation, rather than its ice-free extent or surface temperatures. We investigate the parameter space between Earth and an all-tropics world using the open-source GCM Isca, developed by Vallis et al (2018). We take an Earth analog and perform a parameter sweep in three dimensions: global reservoir depth (1000m, 100m, 10m, 1m, 1cm); global saturation vapor pressure (1.5x current, 1.4x, 1.3x, 1.2x, 1.1x, 1x); and rotation rate (16 days, 8 days, 1 day). The sweep will allow us to explore the effects of surface liquid coverage, atmospheric moisture content, and large-scale atmospheric circulation on an Earth-like climate. In this presentation we provide a status report and analysis of initial findings.
NOMAD on ExoMars TGO: Data processing and public release via the ESA Planetary Science Archive
Authors: Thomas Ian , Vandaele Ann Carine , Daerden Frank , Ristic Bojan , Willame Yannick , Depiesse Cedric , Aoki Shohei , Trompet Loic , Erwin Justin , Robert Severine , Piccialli Arianna , Neary Lori , Viscardy Sebastien , Mason Jon , Patel Manish , Bellucci Giancarlo , Lopez-Moreno Jose Juan
Published: October 2020

NOMAD is a suite of three spectrometers on-board the ExoMars Trace Gas Orbiter. The spectrometers operate in solar occultation, nadir and limb observing modes, measuring in the infrared (2.2-4.3um in occultation; 2.2-3.8um in nadir) and UV-visible (0.2-0.65um) spectral regions. The nominal science phase began on 21st April 2018; since then NOMAD has collected over one Martian year of data.Due to the very high spectral and spatial resolution of NOMAD, an enormous amount of data has already been generated - including tens of millions of solar occultation and nadir spectra - which currently total around four terabytes and are spread across almost half a million files. To serve the scientific community, all calibrated data will eventually be made publicly available in PDS4 format via the ESA Planetary Science Archive at At the time of writing, the NOMAD data collection has successfully passed peer review, and data from two of the three channels will be available very shortly. This first release will consist of: 1) infrared solar occultation data; 2) UV-visible solar occultation data; and 3) UV-visible nadir data. The infrared nadir and infrared and UV-visible limb data will be released later, once the calibration is finalised. In this presentation I will update the scientific community on the current status of the NOMAD PSA archive, including a description of the data and how to start using it.
Modelling of the Electrical Conductivities in the Atmosphere of Ice Giants
Authors: Molina-Cuberos Gregorio J. , Witasse Olivier , Montmessin Frank , Berthelier Jean-Jacques
Published: October 2020

Many studies were carried out recently regarding the exploration of Ice Giants, in the context of the next NASA decadal survey in planetary sciences and astrobiology, of the next planning cycle in ESA's Science Programme, and of a possible NASA-ESA collaboration. A mission to an Ice Giant could include an atmospheric probe, to operate in the 1-10 bars pressure range. Its payload could comprise sensor(s) devoted to the measurement of electrical properties, plasma densities and conductivities.In order to check the performances of such instruments, it is necessary to develop models of the electron and ion densities profiles, with and without aerosols, from which the electrical conductivities can be derived.A model was developed based on studies performed at Mars and Titan [1-2], which computes the atmospheric positive and negative electrical conductivities between 0.1 and 15 bars in the atmosphere of Neptune and Uranus. In this altitude range, galactic cosmic rays ionize the atmospheric constituents, which react with atmospheric neutrals and aerosols, leading to the formation of ions heavier than the ones produced by cosmic rays. The densities of positive ions, electrons and charged aerosols are obtained by solving their corresponding continuity equations. It has been found that aerosol particles tend to be negatively charged due to the attachment of electrons, as a more efficient process than the attachment of positive ions. Therefore, the electrical conductivity due to negative charges is strongly reduced compared to the one expected when aerosols are not present. However, the electrical conductivity due to positive ions does not change so dramatically. The experimental determination of both components of the electrical conductivity can be useful to understand the properties of aerosols, plasma and electric currents in the atmospheres of Ice Giants.Figure 1 and 2 shows some the first results of the number density and electrical conductivities in the atmospheres of Uranus and Neptune. They were calculated for a cosmic rays flux valid for a heliocentric potential of 100 MV, neglecting the planetary internal magnetic field, a mean ion mass of 100 amu and the aerosol particle distribution reported by Toledo et al. [3-4], which is extended down to the pressure range here considered. References [1] Cardnell, S., et al. (2016), A photochemical model of the dust-loaded ionosphere of Mars, J. Geophys. Res. Planets, 121, doi:10.1002/2016JE005077.[2] Molina-Cuberos, G.J., et al. (2018) Aerosols: The key to understanding Titan's lower ionosphere, Planet. Space Sci, 153, 157 – 162, doi: 10.1016/j.pss.2018.02.007.[3] Toledo et al. (2019), Constraints on Uranus's haze structure, formation and transport, Icarus 0019-1035, doi: 10.1016/j.icarus.2019.05.018[4] Toledo et al. (2020) Constraints on Neptune’s haze structure and formation from VLT observations in the H-band, Icarus, doi: 10.1016/j.icarus.2020.113808
Development of a database of Jovian magnetodisc crossings by Galileo and Juno spacecraft from magnetometer data
Authors: Alekseev Igor , Belenkaya Elena , Lavrukhin Alexander , Parunakian David , Pensionerov Ivan
Published: October 2020

Jovian magnetosphere has   a huge equatorial plasma disk, which is also known as the current sheet or magnetodisk. This current sheet enlarges the subsolar magnetosphere size more than twice compare to purely planetary dipole magnetosphere. Near to the planet   the magnetodisk is aligned with the magnetic equatorial plane. As consequence of the dipole axis tilted to the polar axis about 10, each of Juno orbits crossed the central surface of the disk current two times during one jovian day (9, 92 hours). Finally, we have  about 1725 current sheet crossings to study the plasma sheet and current sheets structure.In our work we have developed a database of Jovian current sheet crossings, performed by Galileo and Juno spacecraft, which includes magnetic field and plasma measurements. Current sheet crossings were determined using magnetometer data in distant magnetosphere as a region with the magnetic field strength less than the dipole value at the same point and central current sheet position have been marked by boundary between the region with opposite signum of the radial magnetic field component.
Determination of the Noise Floor of the WHISPER instrument on Cluster
Authors: Middleton Helen , Laakso Harri , Masson Arnaud , Vallières Xavier
Published: October 2020

The WHISPER (Waves of HIgh frequency and Sounder for Probing of Electron density by Relaxation) instrument is part of the WEC (Wave Experiment Consortium) of the ongoing Cluster mission, launched almost 20 years ago in 2000. It uses the long double sphere electric dipole antennas of the EFW (Electric Field and Wave) instrument to measure the electric field spectra in the frequency range 2-80 kHz. The characteristic signatures of natural or actively triggered waves indicate the nature of the ambient plasma regime and, combined with the spacecraft position, reveals the position of key magnetospheric boundaries encountered during a specific time interval.Most of the time, WHISPER observes natural waves in the 2-80 kHz band, using one of the two EFW antennae pairs: Ey or Ez, which can have different characteristics. After successive technical problems with the EFW sensors, the receiving antenna had to be changed on 3 of the 4 spacecraft over the years, and Cluster 1 (C1) WHISPER measurements are currently being made with only one probe (the spacecraft acts as the second probe).In order to understand the signals observed by the WHISPER experiment, one needs to know the instrumental noise floor, around which the measurements are meaningless. It is a frequent feature of wave detectors that this noise floor is temporally static - it does not degrade with time. However, what this noise floor actually is, and how its behaviour changes around the failure of probes and switching to other probes is the purpose of this study. The NATURAL spectra were processed orbit by orbit, in order to avoid strong emissions from any one region, then the minimum value for the low-energy spectra was picked out for each frequency. Individually, these show a large amount of variation, but the median of 20 orbits gives a very reproducible curve showing how the noise floor varies with frequency. The periods before, during and after probe failures and configuration changes were investigated and show the limited changes to the curves and strength of interference lines.
Velocity vectors in the Venus wake unrelated to the J x B force
Authors: Pérez-de-Tejada Hector , Lundin Rickard
Published: October 2020

A useful property of the direction of the ion velocity vectors measured across the Venus wake is that they retain a nearly unchanged configuration; that is, the flow orientation maintains an orderly distribution. Evidence to support this view is provided by the flow pattern presented in the top left panel of Figure 1. The average velocity vectors of the planetary O+ ions collected in several orbits of the VEX spacecraft remain well organized along the tail with some of them displaying a common deflection towards the Y axis. That pattern is entirely different from the erratic distribution of the magnetic field vector orientation presented in the top right panel of that figure. The varying direction of the magnetic field vectors differs from the well organized orientation of the velocity vectors which thus is not influenced by changes of the magnetic field direction; namely, their orientation is not dependant on the J x B force. Their direction of motion is subject to a combination of the solar wind aberration force and the Magnus force along the Y-axis as indicated in the top  left panel of Figure 1. As a result the direction of the velocity vectors of the planetary ions is not solely controlled by the J x B force. Other forces mostly derived from wave-particle interactions are necessary to justify the organized distribution of the velocity vectors of the streaming flow. The data presented here thus provide an important source of information regarding the orderly direction of the ion velocity vectors along the tail which is unrelated to the J x B force.A general displacement of the velocity vectors of the solar wind in the Venus wake in the southbound direction is illustrated in the bottom panel of Figure 1. Measurements conducted with the ASPERA instrument show an overall tendency for the flow to shift towards the –Z  direction as it has been reported from the data obtained in several VEX orbits (Perez-de-Tejada and Lundin (EPSC-DPS 2019 – 184-1,Vol. 13. 2019),The tendency of the vortex structure to shift to lower negative Z values with increasing X distances downstream from Venus is more noticeable in orbits approaching maximum conditions of the solar cycle. A comparable difference is also measured in the different width values of the vortex structures becoming smaller during solar cycle maximum conditions.Figure 1. Average values of the planetary O+ velocity vectors (top left panel) and the magnetic field vectors (top right panel) measured with the VEX spacecraft along the Venus tail. The direction of the velocity vectors exhibits an orderly configuration while the magnetic field vectors become erratic. Red and blue arrows correspond to Z > 0 and Z < 0 locations.  (Bottom panel) Schematic view of the corkscrew shape in the distribution of average values of velocity vectors of planetary O+ ions inferred from measurements in several VEX orbits as the ions move downstream from Venus.
Exoplanet Atmospheres with HST: An open science framework for the characterisation of exoplanets
Authors: Tsiaras Angelos
Published: October 2020

The field of exoplanets is one of the most rapidly growing, with more than 4000 new planets discovered over the past 25 years. In the last decade, we have entered in a new era, the era of exoplanet characterisation, where studies are also focused on understanding more about individual exoplanets, through follow-up observations. Follow-up observations can be used to better constrain the architecture and the dynamics of the planetary system, to detect and characterise the atmospheres of the planets in the system, and to efficiently plant future dedicated observations. Many ground and space-based observatories contribute to this effort from different perspectives already, and new ones are being designed at the moment. In addition, more exoplanets are being discovered on a daily basis. Overall, the variety and the amount of follow-up observations are increasing year by year. In this context, the effort of characterising exoplanets calls for an efficient way of extracting the most information out of all the available observations and sharing this with the community, though a centralized platform open to as many members of the community as possible. While many observatories provide publicly available data, in such a rapidly growing and diverse field a really open platform cannot be limited to sharing open access data alone.In this talk I will discuss about the contribution of the Hubble Space Telescope to the characterisation of a population of exoplanet atmospheres over the last 10 years, emphasising the importance of publicly available data but also the limitations in extracting and sharing the information in them. More specifically, I will focus on the need for dedicated data archives and publicly available data analysis tools.  Also, I will discuss how the lessons learned can be used as a prototype for an open platform for the characterisation of exoplanets in the future.
Hunting for Methane on Mars: one Martian year of survey with ACS on TGO
Authors: Montmessin Franck , Korablev Oleg , Fedorova Anna A. , Trokhimovskiy Alexander V. , Lefevre Franck , Baggio Lucio , Belyaev Denis A. , Olsen Kevin , Alday Juan , Irbah Abdenour , Lacombe Gaetan , Patrakeev Andrey , Teinturier Lucas , Ignatiev Nikolay , Luginin Mikhail , Shakun Alexey , Guerlet Sandrine , Forget François , Millour Ehouarn , Wilson Colin F.
Published: October 2020

AbstractThe Atmospheric Chemistry Suite (ACS) [1], one of the four science experiments on board ESA-Roscosmos ExoMars 2016 Trace Gas Orbiter (TGO) mission has started science operations in March 2018. ACS consists of 3 infrared spectrometers targeting the unambiguous detection of trace gases of potential geophysical or biological interest. The dataset reported here concerns the methane detection attempts conducted during the first complete Martian year (almost two Earth years) of observations using ultra-sensitive occultation observing mode in orbit around Mars.The Trace Gas Orbiter (TGO) of the ESA-Roscosmos ExoMars mission has ended its trip to Mars, reaching the planet in October 2016. After a year-long aerobraking phase, its scientific mission has begun on April 22nd, 2018 with the execution of the first solar occultation. The primary objective of TGO is to detect, map and locate trace gas sources, possibly revealing a residual geophysical (or even biological) activity on Mars. The instrument of interest here is the infrared spectrometer Atmospheric Chemistry Suite (ACS). ACS covers a wavelength range from 0.7 to 17 μm at very high spectral resolution (λ / Δλ from 5,000 to 50,000). ACS operates in nadir and solar occultation. Its performances complete the TGO trace gas detection arsenal together with NOMAD, the other infrared sounder of TGO.A large part of the first months of the ACS observing mission has enabled the sensitive search of gaseous methane over a substantial fraction of the Martian globe. The results from the first occultation up until early September 2018 will be presented. This period incidentally covered the onset, the full development, and the demise of the Planetary Encircling Dust Event observed by several other instruments orbiting currently around Mars. Observing conditions proved more favourable than anticipated, and it was possible in a few cases to probe the Martian atmosphere close to the surface (
Io's auroral footprints: MHD simulations of the interaction between Io and Jupiter
Authors: Schlegel Stephan , Saur Joachim
Published: October 2020

The electromagnetic interaction between Jupiter and its innermost Galilean moon Io is a prime example for moon-planet and star-planet interaction. Very striking features are the Io Foot Prints (IFP) in Jupiter’s upper atmosphere. With the Juno spacecraft orbiting Jupiter, new insights about the complex structure of the IFP and the associated tail have been achieved which can not be fully explained by existing models. A deeper understanding is necessary to explain these Juno observations [Mura et al. 2018]. For that purpose a simulation of the system with the single fluid MHD-Code Pluto is set up to study the Alfvén wing generated by Io in detail. In our study, we use a model similar to Jacobsen et al. 2007 with a constant magnetic field and spatially varying density. Then we increase the complexity of this model by including a more realistic wave generator, i.e. Io, and a more complex model of the Jovian inner magnetosphere. Here, we focus on the reflection pattern of the Alfvén wings at the torus boundary and the Jovian ionosphere and how it affects the morphology and the properties of the Alfvén wings.
Asteroid phase curve parameters from Gaia photometry
Authors: Martikainen Julia , Fedorets Grigori , Penttilä Antti , Muinonen Karri
Published: October 2020

Asteroids have remained mostly the same for the past 4.5 billion years, and provide us information on the origin, evolution and current state of the Solar System. For the physical characterization of asteroids, one of the best data sources is photometry: the measurement of the disk-integrated brightness of the asteroid.  An asteroid's lightcurve (i.e. the dependency of the brightness as a function of time) is indicative of its surface scattering properties, as well as its shape and the state of spin. In this work, we apply novel Bayesian inverse methods (Muinonen et al., A&A 2020, in revision) to derive phase curve parameters from photometric lightcurve observations. Our aim is to validate and expand the existing analyses by applying the methods to of the order of tens to hundreds of asteroids using photometric data from the Gaia Data Release 2 (Gaia Collaboration, Spoto et al., A&A 616, A13, 2018) and ground-based photometry (Durech et al., A&A 513, A46, 2010) from Database of Asteroid Models from Inversion Techniques (DAMIT). We derive phase curve linear slopes by using four techniques:  1) convex inversion on all data, 2) convex inversion on all data with fixed rotation parameters from DAMIT, 3) ellipsoid inversion on Gaia DR2 data only, and 4) ellipsoid inversion on Gaia DR2 data only with fixed rotation parameters from DAMIT. Finally, we compare the obtained slope parameters with the presumed Bus-DeMeo (DeMeo et al., Icarus 202, 160, 2009) taxonomic classes of the asteroids, and study possible correlations with the geometric albedos. The Gaia photometry has milli-magnitude precision and is thus extremely valuable when used to carry out asteroid taxonomic classification.
Towards the second data release of TESS asteroid photometry
Authors: Pál András , Szakáts Róbert , Kiss Csaba
Published: October 2020

By analyzing the full-frame images acquired during the first year of the TESS mission, rotation characteristics of nearly ten thousand light curves of bright asteroids were determined with a good accuracy. The continuation of this space-borne mission with its second year on the Northern Hemisphere is just ending by the summer of 2020, allowing us to extend the database. In this presentation we report the results of the initial analysis of the new data set, focusing on the similarities and differences in observational artefacts (and constraints) and the recent development of the processing pipeline. 
Non-thermal escape on magnetized planets in the TRAPPIST-1 system
Authors: Boldog Ádám , Dobos Vera , Kiss László
Published: October 2020

The TRAPPIST-1 system constists of at least seven Earth-like planets orbiting a red dwarf star. Little is known about the atmospheres of these planets, or whether they were even able to keep them during their lifetime. Since the stellar wind of M dwarf stars is strong enough to evaporate the atmospheres of close-in habitable zone planets, we found it essential to give an estimate on the non-thermal atmospheric escape loss rates on the TRAPPIST-1 planets. Magnetospheres are known to have important roles in these processes, such as providing an obstacle for the stellar wind, but they also permit escape through the polar regions. While some escape mechanisms, like sputtering and ion pickup can be significantly limited given a strong planetary magnetospere, polar wind outflow on the other hand can enhance the total escape rates. In order to account for the effects of magnetic fields, we estimated the magnetic dipole moments, surface magnetic field strength, magnetospheric standoff distances and polar cap areas on all seven planets. We used our calculated dipole moments as input parameters in our simulations to estimate the non-thermal escape loss rates.
Seismic efficiency of Martian upper crust simulant.
Authors: Rajsic Andrea , Miljković Katarina , Collins Gareth , Wünnemann Kai , Wieczorek Mark , Wojcicka Natalia , Daubar Ingrid
Published: October 2020

Introduction: Meteoroid bombardment is one of the sources of seismic activity on planetary bodies. The very first seismometer operating on the surface of another planet was successfully deployed by the NASA InSight (Interior Exploration using Seismic Investigations, Geodesy and Heat Transport) mission to Mars. It gives us an opportunity to investigate the seismicity of Mars, including impact-induced seismic activity. This work investigated the seismic efficiency associated with small meteorite impacts on Mars, using numerical methods in targets analogue to the Martian surface. The Martian crust was simulated as non-porous bedrock (0% porosity) or regolith with different porosities (25%, 44% and 65%)The seismic efficiency, k, is presented as a portion of impact energy that is transferred into seismic energy. It has been suspected that consolidated (bedrock) and non-consolidated (regolith) materials will have different values of seismic efficiency. Estimates of seismic efficiency range from k=10-2 to 10-6 (Schultz and Gault, 1975; Daubar et al., 2018; McGarr et al., 1969; Hoerth et al., 2014; Richardson & Kedar, 2013; Güldemeister & Wünnemann, 2017). High seismic efficiency is typical in bedrock or highly consolidated materials (k>10-3). Low seismic efficiency is typical for sediments or unconsolidated sands and soils (k
Mars and Venus Exploration: A mapping, visualisation, and data analysis application for SPICAM/V high-level science data products
Authors: Cox Nick , Bernard-Salas Jeronimo , Ferron Stephane , Vergely Jean-Luc , Blanot Laurent , Mangin Antoine
Published: October 2020

In the era of big data and cloud storage and computing, new ways for scientists to approach their research are emerging, which impact directly how science progresses and discoveries are made. This development has led the European Space Agency (ESA) to establish a reference framework for space mission operation and exploitation by scientific communities: the ESA Datalabs (EDL). The guiding principle of the EDL concept is to move the user to the data and tools, and to enable users to publish applications (e.g. processors, codes, pipelines, analysis and visualisation tools) within a trusted environment, close to the scientific data, and permitting the whole scientific community to discover new science products in an open and FAIR approach.In this context we will present a proto-type science application (aka Sci-App) for the exploration and visualization of Mars and Venus using the SPICAM/V Level-2 data available from the ESA Planetary Science Archive (PSA). This demonstrator facilitates the extraction and compilation of scientific data from the PSA and ease their integration with other tools through VO interoperability thus increasing their scientific impact. The tool’s key modular functionalities are 1) interactive data query and retrieval (i.e. search archive metadata), 2) interactive visualisation (i.e. geospatial info of query results, data content display of spectra, atmospheric vertical profiles), 3) data manipulation (i.e. create local maps or data cubes), and 4) data analysis (in combination with other connected VO tools). The application allows users to select, visualise and analyse both Level 2A products, which consist of e.g. transmission and radiance spectra, and level 2B products, which consist of retrieved physical parameters, such as atmospheric aerosol properties and vertical density profiles for (trace) gases in the Martian or Venusian atmosphere.Our goal is to deploy the (containerised) Sci-App to the EDL and similar initiatives for uptake by the space science community. In the future, we expect to incorporate access to other Mars/Venus atmospheric data sets, particularly the measurements obtained with the NOMAD and ACS instruments on the ExoMars Trace Gas Orbiter. The community can also use this application as a starting point for their own tool development for other data products/missions.
The influence of crustal magnetic fields on the Martian bow shock : a statistical analysis of Mars Volatile EvolutioN and Mars Express observations
Authors: Garnier Philippe , Jacquey Christian , Mazelle Christian , Fang Xiaohua , Gruesbeck Jacob , Hall Benjamin , Masunaga Kei , Halekas Jasper , Espley Jared , Jakosky Bruce , Genot Vincent , Penou Emmanuel
Published: October 2020

The Martian interaction with the solar wind is unique due to the influence of remanent crustal magnetic fields. The recent studies by the Mars Express and Mars Atmosphere and Volatile Evolution missions underline the strong and complex influence of the crustal magnetic fields on the Martian environment and its interaction with the solar wind. Among them is the influence on the dynamic plasma boundaries that shape this interaction and on the bow shock in particular.Compared to other drivers of the shock location (e.g. solar dynamic pressure, extreme ultraviolet fluxes), the influence of crustal magnetic fields are less understood, with essentially differences observed between the southern and northern hemispheres attributed to the crustal fields. In this presentation we analyze in detail the influence of the crustal fields on the Martian shock location by combining for the first time datasets from two different spacecraft (MAVEN/MEX). An application of machine learning techniques will also be used to increase the list of MAVEN shocks published to date. We show in particular the importance for analyzing biases due to multiple parameters of influence through a partial correlation approach. We also compare the impact of crustal fields with the other parameters of influence, and show that the main drivers of the shock location are by order of importance extreme ultraviolet fluxes and magnetosonic Mach number, crustal fields and then solar wind dynamic pressure.