bluuebunny/crossref_metadata_2025 huggingface dataset:
The multi-wavelength phase curves of minor bodies from the SLOAN Moving Objects Catalog
Authors: Alvarez-Candal Alvaro , Benavidez Paula , Campo Bagatin Adriano , Santana-Ros Toni , Jimenez Corral Santiago
Published: July 2021

Phase curves of minor bodies describe their brightness change with phase angle, once distance effects have been removed. Using phase curves it is possible to obtain absolute magnitudes, useful parameters as they can be used as a proxy of sizes, with limitations due to albedo. In particular, in this work, we present phase curves of several thousands of minor objects in the filter system of the SLOAN Digital Sky Survey (SDSS).We obtained the phase curves using the Moving Object Catalog (MOC) of the SDSS including in the final uncertainties those of the input magnitudes and also the uncertainty due to the likely change in magnitude due to rotational variation of the objects. The final products are the absolute magnitudes Hλ and G12λ, where λ indicates any of the five central wavelengths of the SDSS filter system. We computed colors at zero phase angle, or absolute colors, that are not affected by phase effects and could be used as a benchmark for future studies. We also analyze the behavior at small phase angles (
MAPPS: Science Planning and Simulation Tool for ESA Planetary Missions
Authors: Muñiz Carlos , Cardesin Alejandro
Published: July 2021

The Mission Analysis and Payload Planning System (MAPPS) is a multi-mission software system developed during the last 20 years to support the science operations planning for the ESA planetary missions.Developed initially only to visualise the coverage of MEX experiments onto the Martian surface. Progressively, the tool has been extended to provide planning capabilities and to support other missions operationally. In the past: SMART-1, Venus Express and Rosetta. Today and in the coming years: Mars Express, ExoMars2016, BepiColombo, SolarOrbiter, JUICE and EnVision.The tool main objective is to assist the Science Ground Segment Team (SGS), located at the European Space Astronomy Centre (ESAC) near Madrid, with the complex process of instrument operations scheduling, simulation and validation. The tool receives as inputs the observations requests from the instrument teams, which are merged into a plan that the science operations engineers can run. The instruments are simulated and modelled extensively, allowing to find any possible conflict or constraint violation in the plan. The result of a validated plan is the generation of a multi-instrument operational timeline that is sent to the MOC for uplink to the spacecraft.                                                                  Here we present the latest MAPPS features that help the SGS Teams in ESA to achieve their goal of planning scientific operations in an efficient and optimised way.                                                                               
Dust, Field and Plasma instrument onboard ESA’s Comet Interceptor  mission
Authors: Rothkaehl Hanna , Andre Nicolas , Auster Uli , Della Corte vincenzo , Edberg Niklas , Galand Marina , Henri Pierre , De Keyser Johan , Kolmasova Ivana , Morawski Marek , Nilsson Hans , Prech Lubomir , Volwerk Martin , Goetz Charlotte , Gunell Herbert , Lavraud Benoit , Rotundi Alessandra , Soucek Jan
Published: July 2021

The main goal of ESA’s F-1 class Comet Interceptor mission is to characterise, for the first time, a long period comet; preferably a dynamically-new or an interstellar object. The main spacecraft, will have its trajectory outside of the inner coma, whereas two sub-spacecrafts will be targeted inside the inner coma, closer to the nucleus. The flyby of such a comet  will offer unique multipoint measurement opportunity to study the comet's dusty and ionised environment in ways exceeding that of the previous cometary missions, including Rosetta. The Dust Field and Plasma (DFP) instruments located on both the main spacecraft A and on the sub-spacecraft B2, is a combined experiment dedicated to the in situ, multi-point study of the multi-phased ionized and dusty environment in the coma of the target and  its interaction with the surrounding space environment and the Sun. The DFP instruments will be present in different configurations on the Comet Interceptor spacecraft A and B2. To enable the measurements on spacecraft A, the DFP is composed of 5 sensors; Fluxgate magnetometer DFP-FGM-A, Plasma instrument with nanodust and E-field measurements capabilities DFP-COMPLIMENT, Electron spectrometer DFP-LEES, Ion and energetic neutrals spectrometer DFP-SCIENA  and Dust detector DFP-DISC. On board of spacecraft B2 the DFP is composed of 2 sensors: Fluxgate magnetometer DFP-FGM-B2 and Cometary dust detector DFP-DISC. The DFP instrument will measure magnetic field, the electric field, plasma parameters (density, temperature, speed), the distribution functions of electrons, ions and energetic neutrals, spacecraft potential, mass, number and spatial density of cometary dust particles and the dust impacts.   The full set of DFP sensors will allow to model the comet plasma environment and its interaction with the solar wind. It will also allow to describe the complex physical processes including wave particle interaction in dusty cometary plasma. 
Mixing region over a surface of cometary nucleus with small-scale inhomogeneities. II Active spots on a less active background surface.
Authors: Zakharov Vladimir , Bykov Nikolay , Rodionov Alexander , Ivanovski Stavro , Della Corte Vincenzo , Rotundi Alessandra , Fulle Marco , Marschall Raphael
Published: July 2021

Contemporary missions to comets allow reconstruction of the nucleus shape in a very high resolution. The real surface of cometary nucleus has complex topography and morphology which results in highly nonuniform gas emission even on a small spatial scale. Numerical simulation from the real surface considering all details is either impossible or excessively computationally expensive. In practice, the real surface is substituted by some ``effective" shape model suitable for numerical simulations but with less number of surface facets (i.e. with less resolution). Each of the surface facets, constituting the shape model separately is assumed to be homogeneous and having the averaged properties of the real surface, which it covers. The correctness of such representation (degradation) of the real surface was studied previously in [1] for the case of active spots on an inactive surface. The present study considers the active spots on the less active background surface.  In the present work we consider a pedagogic case – a spherical surface with surface gas production formed by (1) the gas emission qi from a set of closely located (with interval L) spots (see Fig.1) with sizes li much smaller than the radius of the sphere Rn, and (2) the gas emission qb from the surface outside the spots (i.e. the background).    Conventionally the flow from an inhomogeneous surface can be divided into two regions: (1) a mixing region; and (2) a uniform flow. The flow in the mixing region is multidimensional i.e. with variation of parameters not only along the radial direction. The uniform flow is a result of viscous dissipation of the flow in the mixing region and it is one dimensional with variation of parameters along the radial direction only (as it would be in the case for the expansion from a homogeneous sphere). We study the structure of the flow in the mixing region for different combinations of li, L, qi, qb and define parameters of the resulting uniform flow. Due to a large number of spots it is possible with sufficient precision to restrict the computational domain as shown in Fig.2.In the present study the postulated production rates and relative activity of the background are 1021
The best place and time to live in the Milky Way
Authors: Spinelli Riccardo , Ghirlanda Giancarlo , Haardt Francesco , Ghisellini Gabriele , Scuderi Giorgio
Published: July 2021

Several factors contribute to the emergence and development of life on planets. In addition to local factors (e.g. intrinsic planetary properties and host-star characteristics), planetary habitability can be influenced by the larger scale radiation environment of the Galaxy. Powerful astrophysical transient sources of high energy radiation, like Gamma Ray Bursts (GRBs) and Supernovae (SNe), can be life-threatening and potential cause of mass extinctions. A typical GRB at one kiloparsec distance from a planet with an Earth like atmosphere would destroy most of the ozone layer, expose the biota to harmful UVB radiation from the parent star, and trigger global cooling (due to the increase of the NO2 atmospheric concentration). Indeed, the late Ordovician mass extinction event (~440 million years ago) may have been caused by a GRB. GRBs are approximately 106 times more energetic than SNe but their rate is ~10,000 times lower. Both classes of transients share a stellar origin, either from the core collapse of very massive stars or from binaries of compact objects. The rate of both classes is higher in environments characterized by intense star formation. However, long GRBs prefer relatively low metallicity star forming sites. Moderately metal polluted regions seem to be the preferred sites for the formation of Earth-like planets potentially suited to harbour lifeforms. Therefore, the threats posed by GRBs and SNe to the emergence and development of life in the Milky Way depend in a not obvious way on the past 12 billion years of evolution of the star formation rate (Fig. 1), and relative metal pollution of the interstellar medium (Fig. 2).  On these grounds, we identify where and when, in the Galaxy, life had the best chances of success against lethal cosmic explosions.         We model the lethal effect of GRBs and SNe by scaling their cosmic rates to the MW. GRBs and all SNe rates are proportional to the gas to stars conversion rate within galaxies. In the Galaxy the conversion of gas into stars increased over the past 12 billion years from the center towards the outskirts. Metallicity of newly born stars followed a similar inside-out evolution (Fig. 1 and 2). At different epochs, the number of lethal events as a function of the distance from the center of the Galaxy (Fig. 3) is computed by scaling the cosmic rate to the MW evolving properties (i.e. star formation and metallicity).                                                    In the early stages of the MW evolution (from its formation up to 6 billion years ago) the largest portion of the Galaxy out to 10 kpc from the center was unsuitable to life growth due to the high frequency of lethal events (i.e. > 30 every 500 million years).  Although the MW outskirts appear as a safer place to live (green contours in Fig.3), the low density (
Educational Resources for EPN24 Planetary Field Analogue Sites
Authors: Thompson Tony
Published: July 2021

The Europlanet 2024 Research Infrastructure (RI) provides free access to the world’s largest collection of planetary simulation and analysis facilities. The project is funded through the European Commission’s Horizon 2020 programme and runs for four years from February 2020 until January 2024. The Transnational Access (TA) programme supports all travel and local accommodation costs for European and international researchers to visit over 40 laboratory facilities and 6 Planetary Field Analogues (PFA) [1].As part of the education and inspiration tasks associated with Europlanet 2024 RI, we have produced classroom resources aimed at age 10-14 year olds relating the conditions found within the PFA sites to astrobiology and the habitability of Mars.These resources have been produced around all PFA sites:Rio Tinto River (Spain)
Iceland Field Sites (Iceland)
Danakil Depression (Ethiopia)
Kangerlussuaq Field Site (Greenland)
Makgadikgadi Salt Pans (Botswana)
Andes (Argentina)
These resources link in with common areas found in worldwide STEM curriculums, such as volcanism, pressure, pH and evaporation. To achieve this, we have filmed lab-based demonstrations and included them in a classroom lesson plan alongside teachers' notes. In addition, each lesson plan focuses on how the conditions of the PFAs could affect the habitability of Mars.An Italian version of the resources has been produced by EduINAF with the addition of brief video-lessons.  English versions were released on a weekly basis from mid-March through April with opportunities for training sessions to support teachers wishing to engage with these resources.Following studies such as Salimpour et al 2020 [2], highlighting the extent to which astronomy has been incorporated into school curriculums, we have chosen to highlight three subject areas with lower representation in high schools into our resources: physics, space exploration and astrobiology.As these analogue sites can be linked to more planetary bodies than just Mars, our next steps are to create similar resources based around the habitability of the icy moons of the Solar System.
CH4 abundance in Jupiter's upper atmosphere: A re-analysis of the ISO/SWS 3.3 µm non-LTE emission
Authors: López-Puertas Manuel , Sánchez-López Alejandro , García-Comas Maya , Funke Bernd , Fouchet Thierry , Snellen Ignas
Published: July 2021

CH4 plays a key role in the thermal structure of Jupiter's upper atmosphere and hence knowing its vertical distribution is crucial for its understanding. Methane concentrations have been inferred previously from the analyses of solar occultation, He and Ly-α airglow, and the ISO/SWS radiance measurements around 3.3 µm, showing all rather different values, particularly around the homopause. Even different analyses of the same ISO/SWS radiance spectra yield very different CH4 volume mixing ratio profiles. Here, we present a new analysis of the ISO/SWS radiance spectra by using a comprehensive non-Local Thermodynamic Equilibrium (non-LTE) model and the most recent collisional rates measured in the laboratory. Further, we briefly discuss the potential effects of non-LTE on CH4 3.3 µm emission of temperate Jupiter exoplanets.
Magnetic Fields, Atmospheres, and the Connection to Habitability (MACH) – Using Team Science to determine how magnetic fields influence habitability
Authors: Brain Dave , Peterson William , Cohen Ofer , Cravens Tom , France Kevin , Futaana Yoshifumi , Glocer Alex , Holmström Mats , Kistler Lynn , Ma Yingjuan , Peticolas Laura , Ramstad Robin , Seki Kanako , Strangeway Robert , Vidotto Aline
Published: July 2021

In order to determine the extent to which a global magnetic field is required for a planet to be habitable at its surface, expertise is required from diverse communities, some of which have diverged from each other over the past several decades. For example, modelers and observers of the terrestrial magnetosphere have limited overlap and interaction with modelers and observers of unmagnetized planets or the giant planets in our solar system. There is relatively limited interaction between any of the above communities and those who study exoplanets, though efforts are increasing to bridge the solar system and exoplanet communities. We describe a NASA Heliophysics DRIVE Science Center selected to answer the central question of this session: “Do Habitable Worlds Require Magnetic Fields”. This Center, named MACH (Magnetic Fields, Atmospheres, and the Connection to Habitability) includes scientists who study atmospheric escape from Earth, unmagnetized planets, and exoplanets. Over the next several years MACH will construct a framework that enables the evaluation of atmospheric loss from an arbitrary rocky planet, given information about the planet and its host star. The MACH Center hosted a community-wide workshop in June 2021 centered around this topic, and is seeking to grow their interactions with interested scientists from relevant disciplines.
Entry Probe Radio Science for Measurements of  Ice Giant Atmospheric Dynamics and Composition 
Authors: Atkinson David H. , Asmar Sami W. , Preston Robert A. , Hofstadter Mark
Published: July 2021

Planetary atmospheric winds, waves, tides, and turbulence represent a tie-point between planetary structure and processes, including atmospheric thermal and energy structure, cloud location and properties, and atmospheric composition and compositional gradients. The only direct means by which dynamics of an ice giant atmosphere can be measured along the probe descent path is via radiometric tracking of an ice giant entry probe. Additionally, measurements on an orbiter of the strength of a probe telecom signal can be used to provide the abundance of microwave absorbing molecules along the probe relay signal raypath, expected to be primarily ammonia (NH3) or hydrogen sulfide (H2S).

 

Doppler tracking of a descent probe has been demonstrated with the Galileo probe at Jupiter and the Huygens probe at Titan. By including an ultrastable oscillator on both the transmit and receive sides of the probe telemetry relay signal, the time variation of the measured relay signal frequency provides a measure of wind speeds (via the Doppler effect). and the signatures of atmospheric waves, convection, and turbulence. In addition, other probe dynamical effects such as pendulum motion under the parachute, probe spin, and aerodynamic buffeting can be retrieved from careful analysis of the probe telecom signal Doppler residuals. Measurements made on board the orbiter of the time-varying received signal strength would provide a profile of microwave absorbing molecules along the probe radio signal raypath, complementing composition measurements made the probe mass spectrometer.

 

The scientific objectives, measurement requirements, and expected measurement accuracies of the profile of zonal winds and atmospheric absorption will be discussed in this presentation, with a preliminary attempt to quantify the effect of uncertainties in the reconstruction of the probe descent and carrier overflight trajectories.
Overview of the Nancy Grace Roman Space Telescope Coronagraph Instrument and Its Technology Demonstration
Authors: Zellem Robert
Published: July 2021

After JWST, NASA’s next flagship astrophysics mission is the ambitious Nancy Grace Roman Space Telescope. Roman will include the Coronagraph Instrument (CGI) will be the first high-performance stellar coronagraph using active wavefront control for deep starlight suppression in space, providing unprecedented levels of contrast, spatial resolution, and sensitivity for astronomical observations in the optical. During its Technology Demonstration phase, CGI will resolve the signal of an exoplanet via photometry and spectroscopy and directly image and measure the polarization of disks. Future flagship mission concepts (e.g., HabEx and LUVOIR) aim to characterize Earth analogues with visible light flux ratios of ~10-10, and CGI is a critical intermediate step toward that goal, with predicted capability of ~10-9. Here, we present CGI’s design and capability as well as some anticipated results from its technology demonstration.
Mushballs and the lack of Ammonia in Uranus and Neptune
Authors: Guillot Tristan
Published: July 2021

Observations at radio wavelengths have shown that ammonia is absent of the atmospheres of Uranus and Neptune, even down to pressures of tens of bars. Recently, the detection of H2S at relatively low pressures, from infrared measurements, provided a definitive confirmation of this finding: In the presence of NH3, sulfur should be sequestered into NH4SH, preventing the presence of H2S and of an H2S condensation cloud at low pressures. The situation can be explained with the same approach as to explain the relative depletion of ammonia in Jupiter.  Within violent storms, ammonia vapor can combine with water ice crystals to melt them, form water-ammonia hailstones ("mushballs") that lead to an efficient transport of both species into the deeper atmosphere. I will show that while in Jupiter, equilibrium chemistry predicts the mushball seed region to be confined to a narrow parameter space, it is much more extended in Uranus and Neptune, implying that the process should be much more efficient, thus explaining the relative lack of detectable ammonia in these planets. The extent of the ammonia (and potentially water) depletion region is however unknown. Being able to determine how deep these species are transported will require a dedicated mission to map the deep atmospheric structure and understand moist convection in planets with hydrogen atmospheres. 
Ice Giant Ring Seismology
Authors: A'Hearn Joseph , Hedman Matthew , Mankovich Christopher , Marley Mark
Published: July 2021

We investigate the prospect of using ring seismology to probe the interiors of the ice giants Uranus and Neptune. We produce normal mode spectra for different interior models of Uranus using the program GYRE. These normal mode spectra provide predictions of where in the rings of Uranus we might see effects of interior oscillations. The inner rings of Uranus look to be a promising location for identifying planetary normal mode resonances. The diversity of normal mode spectra implies that identification of even one or two modes in the rings of Uranus would eliminate a variety of interior models, and thus aid in the interpretation of Voyager observations and future spacecraft measurements. In addition, these calculations should show what aspects of the planets’ internal structure can be probed with ring seismology.
J-PLUS: A first glimpse at spectrophotometry of asteroids – The MOOJa catalog
Authors: Morate David , Marcio Carvano Jorge , Alvarez-Candal Alvaro , De Prá Mário , Licandro Javier , Galarza Andrés , Mahlke Max , Solano-Márquez Enrique
Published: July 2021

The Javalambre Photometric Local Universe Survey (J-PLUS) is an observational campaign that aims to obtain photometry in 12 ultraviolet-visible filters (0.3–1 μm) of ∼8 500 deg2 of the sky observable from Javalambre (Teruel, Spain). Due to its characteristics and strategy of observation, this survey will let us analyze a great number of Solar System small bodies, with improved spectrophotometric resolution with respect to previous large-area photometric surveys in optical wavelengths.The main goal of this work is to present here the first catalog of magnitudes and colors of minor bodies of the Solar System compiled using the first data release (DR1) of the J-PLUS observational campaign: the Moving Objects Observed from Javalambre (MOOJa) catalog.Using the compiled photometric data we obtained very-low-resolution reflectance (photospectra) spectra of the asteroids. We first used a σ-clipping algorithm in order to remove outliers and clean the data. We then devised a method to select the optimal solar colors in the J-PLUS photometric system. These solar colors were computed using two different approaches: on one hand, we used different spectra of the Sun, convolved with the filter transmissions of the J-PLUS system, and on the other, we selected a group of solar-type stars in the J-PLUS DR1, according to their computed stellar parameters. Finally, we used the solar colors to obtain the reflectance spectra of the asteroids.We present photometric data in the J-PLUS filters for a total of 3 122 minor bodies (3 666 before outlier removal), and we discuss the main issues of the data, as well as some guidelines to solve them.
Mapping a Duck: Geological Features and Region Definitions on Comet 67P/Churyumov-Gerasimenko
Authors: Besse Sébastien , Leon-Dasi Mireia , Grieger Bjorn , Kueppers Michael
Published: July 2021

Introduction:  The data from the Rosetta mission enabled the reconstruction of the shape of comet 67P/Churyumov-Gerasimenko (hereafter 67P) and the identification of the terrains and features forming its surface. The highly irregular  shape of the comet poses a challenge for the depiction of these geological features on two-dimensional maps.Techniques: Standard global map projections cannot display the complete surface of 67P because different points on the surface can have the same longitude and latitude.  As a consequence, the geological maps published to date are created on top of comet images, making them dependent on the viewing angle and image coverage and resolution.Here, we make use of the recently published Quincuncial Adaptive Closed Kohonen (QuACK) map [1]. It projects the complete surface of 67P unambiguously onto a square. The QuACK map is topologically equivalent to the Peirce quincuncial projection of the world, which makes it possible to define generalized longitudes and latitudes. These can be used within any global map projection in order to obtain an unambiguous QuACK version. Results: The mapping of geological features is carried out in three dimensions employing the Small Body Mapping Tool (SBMT), Fig. 1. We use images from the OSIRIS Narrow Angle Camera aboard Rosetta which have been projected onto the shape model of the SBMT, Fig. 2. The three-dimensional coordinates are then projected onto two-dimensional maps, either in the QuACK map projection or in the QuACK version of the equidistant cylindrical projection, Fig. 3. We present individual maps for 17 of the 26 regions of 67P, mostly located in the northern hemisphere. The new maps combine features published in previous studies with newly identified features.We discuss the distribution of geological features and the characteristics of the regions. In order to align region boundaries with geological features, we propose two modifications of region definitions. Products are fully available to the community through the PSA Guest Storage Facility [2]. Fig. 1: OSIRIS image projected onto the shape model using the SBMT. Fig 2: Identification of features in the Hatmehit region from images projected on the SHAP4S shape model and annotated on the SBMT.Fig 3: Combined geological map of regions in North centered QuACK projection.Acknowledgments: The authors thank the European Space Research and Technology Centre and the European Space Astronomy Center faculty councils for supporting this research. M. Leon-Dasi was supported by an internship from the European Space Agency (ESA) at the European Space Astronomy Center, Madrid, in the period March to December 2020.References: [1] Grieger (2019) A&A, 630, doi:10.1051/0004-6361/201834841. [2] Besse, S. et al. (2017) Planetary and Space Science, 10.1016/j.pss.2017.07.013.
The search for radio emission from the exoplanetary systems 55 Cancri, Upsilon Andromedae, and Tau Bootis using LOFAR beam-formed observations
Authors: Turner Jake , Zarka Philippe , Griessmeier Jean-Mathias , Lazio Joseph , Cecconi Baptiste , Enriquez J. Emilio , Girard Julien , Jayawardhana Ray , Lamy Laurent , Nichols Jonathan , de Pater Imke
Published: July 2021

Observing planetary auroral radio emission is the most promising method to detect exoplanetary magnetic fields, the knowledge of which will provide valuable insights into the planet's interior structure, atmospheric escape, and habitability. We present LOFAR-LBA circularly polarized beamformed observations of the exoplanetary systems 55 Cancri, υ Andromedae, and τ Boötis. We tentatively detect circularly polarized bursty emission from the τ Boötis system in the range 14-21 MHz with a flux density of ∼890 mJy and with a significance of ∼3σ. For this detection, no signal is seen in the OFF-beams, and we do not find any potential causes which might cause false positives. We also tentatively detect slowly variable circularly polarized emission from τ Boötis in the range 21-30 MHz with a flux density of ∼400 mJy and with a statistical significance of >8σ. The slow emission is structured in the time-frequency plane and shows an excess in the ON-beam with respect to the two simultaneous OFF-beams. Close examination casts some doubts on the reality of the slowly varying signal. We discuss in detail all the arguments for and against an actual detection. Furthermore, a ∼2σ marginal signal is found from the υ Andromedae system and no signal is detected from the 55 Cancri system. Assuming the detected signals are real, we discuss their potential origin. Their source probably is the τ Bootis planetary system, and a possible explanation is radio emission from the exoplanet τ Bootis b via the cyclotron maser mechanism. Assuming a planetary origin, we derived limits for the planetary polar surface magnetic field strength, finding values compatible with theoretical predictions. Further low-frequency observations are required to confirm this possible first detection of an exoplanetary radio signal.
Characterising the interior structures and atmospheres of multiplanetary systems.
Authors: Acuña Lorena , Deleuil Magali , Mousis Olivier , López Théo A. , Morel Thierry , Santerne Alexandre , Marcq Emmanuel
Published: July 2021

The increasing number of well characterised low-mass planets, combined with the valuable informations from stellar and planetary spectroscopy, opens the way to the modeling of planetary structures and compositions, which can be obtained with theoretical and numerical works. This approach gives a valuable insight to understand the formation of planetary systems in the low-mass range. We present a 1D planetary model where the interior is coupled with the atmosphere in radiative-convective equilibirum within a Bayesian retrieval scheme. In addition to a Fe core and a silicate mantle, we take into account water in all its possible phases, including steam and supercritical phases, which is necessary for systems with a wide range of stellar irradiations. 

Our interior-atmosphere model calculates the compositional and atmospheric parameters, such as Fe and water content, surface pressures, scale heights and albedos. We analyse the multiplanetary systems K2-138 and TRAPPIST-1, which present six low-mass planets with different densities and irradiations. From the individual composition of their planets, we derive a similar trend for both systems: a global increase on the water content with increasing distance from the star in the inner region of the systems, while the planets in the outer region present a constant water mass fraction. This trend reveals the possible effects of migration, formation location and atmospheric mass loss during their formation history.
A new outlook at Uranus' and Neptune's 10 keV--5 MeV energy electron distributions from data analyses and physics-based models
Authors: Santos-Costa Daniel
Published: July 2021

We present our latest understanding of the processes that shape the spatial distributions of energetic electrons trapped in the magnetospheres of Uranus (L < 15) and Neptune (L < 25). To determine what controls the energy and spatial distributions throughout the different magnetospheres, we compute the time evolution of particle distributions with the help of a diffusion theory particle transport code that solves the governing 3-D Fokker-Planck equation. Different mechanisms of particle loss, source and transport are numerically examined. Our theoretical modeling is guided by the analysis of particle, field and wave data collected during Voyager 2’s flyby of Uranus in January 1986 and at Neptune in August 1989.Our preliminary data-model comparison results at Uranus show that adiabatic transport cannot explain the radial and angular features of warm to ultra-relativistic electron populations within the ~1-15 L region. Our simulation results also suggest that, with absence of loss mechanisms inside L = 15, energetic and radiation-belt electron populations would be higher by 1-3 orders of magnitude in intensity close to the planet (L ~ 1-8). Particularly, our results confirm that moon sweeping effect is a significant loss mechanism at Uranus. Nonetheless, other radial, energy and pitch-angle dependent mechanisms seem to be missing to explain the in-situ data. We will thus present our ongoing effort to examine the role of --for instance, Uranus’ rings system, atomic hydrogen corona and wave activity inward of L ~ 8-10 to improve our modeling of Uranus’ electron populations between L values of 1 and 15.Our first physics-based model of energetic electrons at Neptune will be presented, emphasizing first the role of radial transport and moon sweeping effect for the 1-25 L region before investigating new processes. Our models developed for Uranus and Neptune are based on the theoretical modeling of electron distributions at Saturn, which included the modeling of radial transport and interactions of electrons with Saturn's dust/neutral/plasma environments and waves, as well as particle sources from high-latitudes, interchange injections, and outer magnetospheric region. Comparisons between the distributions of electron populations at Gas and Ice Giant systems will be discussed.Data analysis, theoretical modeling, and numerical computations for Uranus and Neptune are carried out by adapting the Kronian modeling tools developed at Southwest Research Institute to the Ice Giants environment. Key data analysis, theoretical modeling, and numerical computational tasks for Saturn were carried out at Southwest Research Institute under NASA GSFC grant 80NSSC18K1100.
Ice Giants Net Flux Radiometer (IG-NFR) Electrical Architecture
Authors: Tran Dat , Aslam Shahid , Gorius Nicolas , Quilligan Gerard , Nehmetallah George
Published: July 2021

From the Ice Giants Pre-Decadal Survey Mission Report 2017 (IGPDS), a Net Flux Radiometer (NFR) was identified in the IGPDS report as a complementary payload for a probe mission to the Ice Giants. In this paper, we will focus on the electrical architecture of an advanced NFR that is applicable to both Uranus and Neptune. The NFR contains seven spectral channels to measure energy flux from 0.2-300 μm region. The NFR rotates clockwise and anti-clockwise at 5 different viewing angles sequentially and each channel projects an unobstructed 5° field-of-view (FOV) into the atmosphere.  It would enable the scientists to determine an ice giant’s atmospheric heat balance and the tropospheric 3D flow which will lead to deeper understanding the plant’s radiation, region of solar energy deposition and the atmospheric conditions [1], [2], [3], [4]. In this design, thermopile sensors are used as the detector to convert radiation energy to electrical signal. Those thermopiles are uncooled and passive detector which help to reduce overall size, weight and power (SWaP) factor of the instrument. However, the readout noise is dominated by low-frequency noise which limited the resolution of the instrument. To overcome such problem, an application specific integrated circuit (ASIC) with multi-channel analog-to-digital converter has been developed to reduce the low frequency noise of the readout system. A field-programmable-gate array (FPGA) has been integrated to the readout system to truly sample seven channels of the ASIC simultaneously. In this paper, we will go over the details of the ASIC and how to use it with the FPGA to implement the readout system for the advanced NFR. Figure 1 shows the system block diagram of the instrument [5], [6], [7].Figure 1: System block diagram of the instrument[1] Aslam, S., et al., (2019). International Planetary Probe Workshop 2019, Oxford, UK[2] Aslam, S., et al., (2020). Space Science Reviews, 216(1)[3] Aslam, S., et al., (2018). 49th Lunar and Planetary Science Conference 2018, The Woodlands, Texas, USA, Volume: LPI Contrib. No. 2083, 2675[4] Aslam, S., et al., (2021). EPSC Abstracts Vol. 15, EPSC2021-144, 2021 European Planetary Science Congress 2021[5] Tran, D., et al., (2020). Sensors and Systems for Space Applications XIII 11422, 1142205.[6] Tran, D., et al., (2020). Lunar and Planetary Science Conference, 1233.[7] Quilligan, G., et al.,  (2021). IEEE Transactions on Nuclear Science.
A New Probabilistic Model to Evaluate the Age and Erosion Rate of Young Sedimentary Rock on Mars
Authors: Li An , Kite Edwin
Published: July 2021

Abstract:  The Medusae Fossae Formation (MFF) is an enigmatic sedimentary unit in the equatorial region of Mars with an uncertain formation process and age [1, 2]. Due to the heavily wind-eroded surface, it is difficult to determine the age of the MFF using existing crater count data and a one-parameter model based on the crater size-frequency distribution function [2, 3]. In our study, we used Context Camera (CTX) crater counts of 14 sites near the Medusae Fossae Formation, and other young equatorial units, to create a new two-parameter probabilistic model that estimates both age and erosion rate (β) by treating cratering as a random Poisson process. Our model predicts that the Central Medusae Fossae Formation and the top of Aeolis Mons (otherwise known as Upper Mount Sharp) have older ages (>1.40 Ga) and lower erosion rates (10 times faster than our model-fit erosion rates, so we approximate sedimentation rate as instantaneous and treat deposition as one continuous interval before erosion occurs in a following continuous interval to reach present-day volume for each site.Fig. 4 Mound volume history for site 4B: Central Medusae Fossae 2B. The black line in each plot represents the cumulative best fit volume (km3) for each region. The lighter colored cyan section represents the 2σ region and the darker cyan section represents the 1σ region.Discussion and Conclusions:        As seen in Fig. 5, while Central Medusae Fossae and Upper Mt. Sharp had best fit older ages (>1.40 Ga) and best fit lower erosion rates (
Study of the changes of the distribution of spectral properties of S-type asteroidal dynamical families with age: Mean values and Skewness.
Authors: Melita Mario Daniel , Tello-Huanca Eduardo , Kanuchova Zuzana , Strazzulla Giovanni , Brunetto Rosario
Published: July 2021

Correlations between family-age and the mean value of slope of the spectral distribution, caused by the cumulative effect of cosmic irradiation, have been established for S-type dynamical families by many authors. We noticed that if there is a variety in the primordial surface composition, then the typical timescale that determines the speed of this evolution is bound to have a range of values. Consequently, as the mean value of the color distribution tends to steeper (redder) slopes, a progressive skewness in this distribution should develop. Using SDSS-MOC-4 colors and NEOWISE albedos, we cross-examined the S-type families members as defined by both Nesvorny et al. (2015) and Spotto et al (2015) and retained only members with albedos and colors in the characteristic range of the S-types. We corroborate the color evolution with age and we compare our results with previous estimations. Using only the "true S-type" family members, we also find a significative correlation between some particular skewness-estimation parameters and age. Our results offer additional evidence of the effects of cosmic-radiation on asteroidal surfaces and may provide possible new relations to determine the age of S-type dynamical families. ReferencesNesvorny D.(2015). NASA Planetary Data System, id. EAR-A-VARGBDET-5-NESVORNYFAM-V3.0Spoto, F.; Milani, A.; Knežević, Z. (2015). Asteroid family ages. Icarus, Volume 257, p. 275-289.
On the Importance of Producing and Characterizing Laboratory Analogs of Planetary Atmospheric Aerosols and Clouds and Their Use to Interpret Observations
Authors: Sciamma-O'Brien Ella , Barth Erika , Bertrand Tanguy , Cook Jason , Cruikshank Dale , Dalle Ore Cristina , Dubois David , Grundy Will , Iraci Laura , Mastrapa Rachel , Roush Ted , Salama Farid , Vinatier Sandrine ,   NASA Center for Optical Constants (NCOC) Team
Published: July 2021

Clouds and hazes play a major role in (exo)planetary atmospheres. They can absorb and reflect light from UV to thermal infrared wavelengths, changing the atmospheric emission, reflection, and transmission spectra dramatically. The organic aerosols forming the haze can act as cloud condensation nuclei. Then can also settle down onto the surface, hence participating in its composition. Dedicated laboratory experiments have been developed to produce solid materials that are analogs of haze and cloud particles, under different experimental conditions (molecular precursors, temperature, pressure, energy source…). These experimental studies are key to investigating the physical and chemical processes that drive the formation of solid particles from gas and solid phase molecular precursors in planetary environments. These experiments also allow the characterization of the physical, optical and chemical properties of the laboratory-generated haze and cloud particle analogs, hence providing critical information that can be used as input parameters in models for the analysis and interpretation of observational data (e.g. optical constants, vapor pressures, spectral features, grain morphology, etc).Here, as examples of these laboratory efforts, we will present various studies that combine (1) experiments performed to produce analogs of Titan and Pluto atmospheric aerosols from gas phase molecular precursors, (2) experiments conducted to simulate the formation of benzene ice cloud particles in Titan’s stratosphere, and (3) experiments carried out to characterize the haze and cloud particle analogs to provide, in particular, optical constants and vapor pressures. We will show how important these studies are for the interpretation of observational data from past, current and future (exo)planetary missions. We will also introduce the newly funded NASA Center for Optical Constants whose overarching goal is to support a stable, long-term, synergistic laboratory effort to address a critical need throughout the broader planetary science community for the development of a comprehensive database containing complex refractive indices (optical constants) of laboratory-generated analogs of organic refractory materials, and ices present in planetary atmospheres and surfaces.
Optical and Infrared Phase Curves of the Lava Planet K2-141 b
Authors: Zieba Sebastian , Zilinskas Mantas , Kreidberg Laura , Cowan Nicolas , Nguyen Giang , Miguel Yamila , Pierrehumbert Raymond , Lupu Roxana , Dang Lisa , Hammond Mark , Malavolta Luca , Carone Ludmila
Published: July 2021

K2-141 b is a transiting, small (1.5 RE) Ultra-Short-Period (USP) planet orbiting its star every 6.7 hours discovered by the Kepler space telescope. The planet’s high surface temperature of more than 2000 K makes it an excellent target for atmospheric studies by the observation of its thermal emission. We present 65 hours of continuous photometric observations of K2-141 b collected with Spitzer’s IRAC Channel 2 at 4.5 microns spanning 10 full phases of the orbit. Our best fit model of the Spitzer data shows no significant offset of the thermal hotspot and is inconsistent with the observed offset of the well-studied USP planet 55 Cnc e at a 3.7 sigma level. We measure an eclipse depth of 142 +/- 40 ppm and an amplitude variation of 120 +/- 40 ppm in the infrared. The joint analysis of the observations collected in the two photometric bands favors a non-zero geometric albedo with Ag = 0.26 +/- 0.07 and a tentative temperature gradient. With a dayside temperature of 2141 -361 +352 K and a night-side temperature of 1077 -623 +473 K we also find no evidence of heat redistribution on the planet. We compare the observations to a 1D rock vapor model and a 1D circulation toy model and argue that the data are best explained by a thin rock vapor atmosphere with a thermal inversion.
Exploring the formation of the Arsia Mons Elongated Cloud on Mars
Authors: Hernandez Bernal Jorge , Sánchez-Lavega Agustín , Del Río-Gaztelurrutia Teresa
Published: July 2021

In a recently published paper, we reported the existence and properties of the Arsia Mons Elongated Cloud (AMEC; Hernández-Bernal et al., 2021). We are now exploring models for the theoretical understanding of this outstanding phenomenon.The AMEC forms at sunrise over the western slope of the Arsia Mons volcano, and for ~3 hours expands to the west following zonal winds, leaving behind a characteristic white bright tail. This process repeats in a daily cycle for a long season around the southern solstice. According to observations in MY34, the AMEC reaches a length of up to 1800 km, and expands at a velocity of around 170 m/s (~130 m/s in other years) at ~45 km in altitude. In comparison, winds predicted by the Global Circulation Model LMD-MCD are ~60m/s (Millour et al. 2018).The cloud is clearly driven by upward winds forced by the topography of the volcano. We are analysing from the theoretical perspective the formation and particular features of this cloud.ReferencesHernández‐Bernal, J., Sánchez‐Lavega, A., del Río‐Gaztelurrutia, T., Ravanis, E., Cardesín‐Moinelo, A., Connour, K., ... & Hauber, E. (2021). An extremely elongated cloud over Arsia Mons volcano on Mars: I. Life cycle. Journal of Geophysical Research: Planets, 126(3), e2020JE006517.Millour, E., F. Forget,A. Spiga, et al.  "Mars climate database. (Version 5.3)" From Mars Express to ExoMars (2018)
The next step for Rosetta ROSINA/DMFS data of comet 67P/Churyumov-Gerasimenko: the search for semi-volatiles species.
Authors: Dhooghe Frederik , De Keyser Johan , Altwegg Kathrin , Cessateur Gaël , Jehin Emmanuel , Maggiolo Romain , Rubin Martin
Published: July 2021

Using data from Rosetta/ROSINA’s Double Focusing Mass Spectrometer (DFMS), a zoo of neutral molecules have been discovered in the coma of 67P/Churyumov-Gerasimenko, which led to a wealth of new insights regarding the comet itself, its formation and the early history of our Solar System.A comprehensive understanding of the overall comet composition requires information on all species involved i.e. the volatiles, semi-volatiles and refractories in the coma. However, while ROSINA targets volatiles and GIADA, MIDAS and COSIMA studied refractories, no instrument on Rosetta provides measurements specifically of semi-volatiles. In some circumstances, ROSINA/DFMS may provide at least some information on semi-volatiles in the coma. As semi-volatile species are progressively released from the grains into the gas coma (their release depends on cometocentric distance and grain size), they can be identified if the abundance ratio of a candidate semi-volatile species (or a fragment thereof) to a volatile species increases as a function of distance from the nucleus. This constitutes a so-called distributed source in the coma.With a mass spectrometer like DFMS, one does not detect neutral coma species, but rather the ionized products thereof after electron impact ionization. A major difficulty is assigning the observed ions to parent neutrals. As semi-volatile species have a low abundance, sum spectra obtained through accumulation of individual DFMS spectra can improve the signal-to-noise ratio in order to provide decisive information for identification. Accurate sum spectra can only be obtained provided all instrument-dependent effects are accounted for.This contribution focuses on the procedure used to create sum spectra and presents some typical results.
Photon and thermal processing of CH3NH2-bearing ices. Synthesis of prebiotic species at low temperature (such as formamide, ethylamine, and methylcyanide), and N-heterocycles during warm up.
Authors: Carrascosa Héctor , González Díaz Cristóbal , Muñoz Caro Guillermo M. , C. Gómez Pedro , Sanz María Luz
Published: July 2021

Hexamethylentetramine has drawn a lot of attention due to its potential to produce prebiotic species. This work aims to gain a better understanding in the chemical processes concerning methylamine under astrophysically relevant conditions. In particular, this work deeps into the formation of N-heterocycles in interstellar ice analogs exposed to UV radiation, which may lead to the formation of prebiotic species.Experimental simulations of interstellar ice analogs were carried out in ISAC. ISAC is an ultra-high vacuum chamber equipped with a cryostat, where gas and vapour species are frozen forming ice samples. Infrared and ultraviolet spectroscopy were used to monitor the solid phase, and quadrupole mass spectrometry served to measure the composition of the gas phase. The variety of species detected after UV irradiation of ices containing  methylamine revealed the presence of 12 species which have been already detected in the ISM, being 4 of them typically classified as complex organic molecules: formamide (HCONH2), methyl cyanide (CH3CN), CH3NH and CH3CHNH. Warming up of the irradiated CH3NH2-bearing ice samples lead to the formation of trimethylentriamine (TMT), a N-heterocycle precursor of HMT, and the subsequent synthesis of HMT at temperatures above 230 K.