bluuebunny/crossref_metadata_2025 huggingface dataset:
A portrait of the Trans-Neptunian Object (143707) 2003 UY117 from a stellar occultation and photometry data.
Authors: Ortiz Jose L. , Santos-Sanz Pablo , Sicardy Bruno , Vara-Lubiano Mónica , Morales Nicolás , Fernandez-Valenzuela Estela , Braga-Ribas Felipe , Souami Damya , Castro-Tirado Alberto , Fernández-García Emilio Jesús , Sota Alfredo , Sánchez Miguel , de la Cueva Ignacio , Maestre Jose L. , Popescu Marcel , Guijarro Ana , Jehin Emmanuel , Pozuelos Francisco J. , Licandro Javier , Rodriguez-Alarcon Miguel ,   2003UY117 occultation team
Published: July 2021

Within the Lucky Star international collaboration* on stellar occultations by TNOs and other outer solar system bodies, we predicted the occultation by the TNO (143707) 2003 UY117 of an mV ~ 14.6 mag star on 23 October 2020. Around a week before the occultation date, we updated and refined the prediction using high precision astrometry obtained using the 2 m Liverpool telescope located at El Roque de Los Muchachos Observatory on La Palma, Spain. The update resulted in a shadow path with good observability potential. We carried out a specific campaign involving 27 observing sites in the south of Spain and North of Africa to observe the occultation. We recorded 4 positive detections and several very close misses to the south of the body. With this information we determined the silhouette of 2003 UY117 at the moment of the occultation. We also obtained the geometric albedo and the size for this object. In addition to this, we carried out several photometric runs with large telescopes to determine the rotation period and rotational phase at the time of the occultation. The body presents a clear double-peaked rotational light curve consistent with a triaxial ellipsoid of considerable elongation, which means that a rotational light curve analysis is critical to correctly interpret the occultation results. The preliminary analysis indicates a larger equivalent diameter than that determined from Herschel thermal data, although consistent within the large error bars of the thermal determination. We will present the preliminary results and discuss their implications.*Lucky Star (LS) is an EU-funded research activity to obtain physical properties of distant Solar System objects using stellar occultations. LS collaboration agglomerates the efforts of the Paris, Granada, and Rio teams. https://lesia.obspm.fr/lucky-star/ Acknowledgements:JLO, PS-S, NM, MV, and RD acknowledge financial support from the State Agency for Research of the Spanish MCIU through the ‘Center of Excellence Severo Ochoa’ award for the Instituto de Astrofísica de Andalucía (SEV-2017-0709), they also acknowledge the financial support by the Spanish grant AYA-2017-84637-R and AYARTI2018- 098657-J-I00 ‘LEO-SBNAF’ (MCIU/AEI/FEDER, UE).
Graphene in Titan
Authors: Kushwaha Rahul Kumar , Mallya Ambresh , Sahu Dipen , Meka Jaya Krishna , Chou Sheng-Lung , Wu Yu-Jong , Gupta Divita , Das Ankan , Lo Jen-Iu , Cheng Bing-Ming , Rajasekhar Balabhadrapatruni N , Bhardwaj Anil , Hill Hugh , Padmanabhan Janardhan , Mason Nigel J , Sivaraman Bhalamurugan
Published: July 2021

Benzene (C6H6) ice has been observed in the Titan’s stratosphere [1], and benzonitrile (C6H5CN) is a possible constituent in the benzene and nitrogen-rich environment of Titan’s atmosphere [2]. The energetic processing of such aromatic molecules can synthesize large and complex aromatic molecules such as the Polycyclic Aromatic Hydrocarbons (PAHs). To-date a number of laboratory experiments have reported the formation of complex organics from the energetic processing of aromatic molecules [3-6]. In particular, Scanning Electron Microscopy (SEM) micrographs of the residues resulting from irradiated benzene ices are found to contain geometrically shaped particles [6]. Therefore, by employing electron microscopes, we can understand the physical nature of the dust leftover from the aromatic molecule irradiation.In the present investigation, we subjected benzonitrile ice made at 4 K to vacuum ultraviolet (9 eV) radiation at two beamlines, BL03 and BL21A2 of Taiwan Light Source at NSRRC, Taiwan. After irradiation, the ice was warmed to room temperature, which left a brownish residue on the Potassium Bromide (KBr) substrate. The VUV spectrum of the residue is observed to have characteristic aromatic signatures. The residue is then transferred to a quantifoil grid for High-Resolution Transmission Electron Microscope (HR- TEM) imaging. HR-TEM micrographs revealed the presence of graphene in the residue. This result suggests that N-graphene could be present in benzene and nitrogen-rich icy clouds of Titan. The high masses observed by the Cassini plasma spectrometer in Titan’s atmosphere could then be attributed to the presence of N-graphene along with the more common tholins [7].References[1] Vinatier S. et al. (2018) Icarus, 310, 89.[2] Loison J. C. et al. (2019) Icarus 329, 55.[3] Strazzulla G. et al. (1991) A&A, 241, 310.[4] Callahan M. P. et al. (2013) Icarus, 226, 1201.[5] James R. et al. (2019) RSC Adv. 9 (10), 5453.[6] Rahul K. K. et al. (2020) Spectrochim. Acta A, 231, 117797.[7] Rahul K. K. et al. (2020) arXiv:2008.10011.
On the detectability of the meteor pairs created by fragmentation in near-Earth space
Authors: Koten Pavel , Čapek David
Published: July 2021

Although numerous observers reported that meteors appear in pairs or groups, recent papers based on instrumental observations did not confirm such results. At least, among older meteor showers such grouping was not confirmed. On the other hand, among younger streams, such behaviour is still possible.In our recent paper dedicated to the search of pairs among Geminid meteors, we found that we have no evidence for the physically connected pairs despite the fact that a number of potential candidates have been detected. Monte Carlo statistical test showed that all the cases can be results of coincidental approaches of the particles in a similar space and time.Therefore, we prepared a model of orbital fragmentation of meteoroids in the vicinity of the Earth, which follows trajectories of fragmented particles ejected with different velocities in different directions under  the solar radiation pressure. The collisions with interplanetary particles as the possible source of the pairs are taken into account for the major meteor showers during whole year. The paper will provide constraints on the time of ejection, ejection velocities and ejection angles, which will allow the pairs or groups to be detected in the Earth atmosphere by the video or photographic cameras.
Exploring the convection in super-Earths: Comparing LHS 3844b with 55 Cnc e
Authors: Meier Tobias G. , Bower Dan J. , Lichtenberg Tim , Tackley Paul J. , Demory Brice-Olivier
Published: July 2021

The vigour and style of mantle convection in tidally-locked super-Earths may be substantially different from Earth's regime where the surface temperature is spatially uniform and sufficiently cold to drive downwellings into the mantle.The thermal phase curve for super-Earth LHS 3844b suggests a solid surface and lack of a substantial atmosphere. The dayside temperature is around 1040 K and the nightside temperature is around 0 K, which is unlike any temperature contrast observed at present day for planets in the Solar System. On the other hand, the thermal phase curve of super-Earth 55 Cnc e suggests much hotter temperatures with a nightside temperature around 1380 K and a substellar point temperature around 2700 K. The substellar point is also substantially shifted eastwards, which requires efficient energy circulation in the atmosphere.Here, we use constraints from thermal phase curve observations to model the interior mantle flow. To constrain the surface temperature of  55 Cnc e, we use the results from general circulation models varying the atmospheric composition and optical depth.Depending on how strong the surface temperature contrast is, this can lead to hemispheric tectonic regimes. Such a regime could influence a planet's atmosphere through interior-exterior coupling mechanisms (e.g. volcanic outgassing).  We run geodynamic simulations of the interior mantle flow using the mantle convection code StagYY. The models are fully compressible with an Arrhenius-type viscosity law where the mantle is modelled with an upper mantle, a perovskite-layer and a post-perovskite layer. The lithospheric strength is modelled through a plastic yielding criteria and the heating mode is either basal heating only or mixed heating (basal and internal heating). For LHS 3844b we find that the surface temperature dichotomy can lead to a hemispheric tectonic regime depending on the strength of the lithosphere and the heating mode in the mantle. In a hemispheric tectonic regime, downwellings occur preferentially on one side and upwellings rise on the other side (Fig. A). We compare these results to the case of 55 Cnc e, where large parts of the surface could be molten. At first order we expect that a magma ocean could homogenise the temperatures at the interface between the magma ocean and the underlying solid mantle and therefore reduce the likelihood of hemispheric tectonics operating on 55 Cnc e (Fig. B).For LHS 3844b, the contribution of the interior flux to the thermal phase curve is on the order of 15-30 K, and therefore below the detecting capabilities of current and near-future observations. However, for hemispheric tectonics, upwellings might lead to preferential melt generation and outgassing on one hemisphere that could manifest as a secondary signal in phase curve observations. Such signals could also be produced on hotter planets such as 55 Cnc e where parts of the surface are hot enough to melt. 
The influence of water and mineralogy on sticking properties at increasing temperatures
Authors: Bogdan Tabea , Pillich Cynthia , Landers Joachim , Wende Heiko , Wurm Gerhard
Published: July 2021

Sticking properties are of great importance for planetesimal formation in protoplanetary disks. During the early phases of pebble growth, grains regularly travel from cold, water-rich regions to the warm inner part of the disk, experiencing ever higher temperatures. This drift leads to changes in composition, grain size, morphology, and water content. To follow the evolution that the dust might go through, we milled a meteorite to micrometer dust and tempered it under vacuum at increasing temperatures up to 1400 K. For each tempered sample we measured the splitting tensile strength of millimeter-sized dust aggregates using a well-established method known as the Brazilian test. To link the evolution of surface energy with temperature to compositional changes, we additionally measured the (ferric) composition of the samples by Mössbauer spectroscopy. At the low pressure of protoplanetary disks and at moderate temperatures, grains presumably hold only a monolayer of surface water and can thus be considered as dry. As the dust drifts further inwards towards higher temperature regions even this monolayer of water may evaporate completely and grains are super dry. In the laboratory, contacts between grains in cylinders are dry and remain dry for measurement if they are prepared for the Brazilian test before tempering. If cylinders are prepared after tempering but from the tempered dust, contacts are wet contacts but the influence of the composition can be traced.For wet samples, we measured an effective surface energy which monotonously decreases by a factor of 5 from room temperature to about 1300 K due to compositional changes [1]. This reduction of surface energy still holds for dry samples but with an increase in the sticking force by a factor of ~ 10 over the wet samples. Super dry samples deviate strongly from this starting at about 900 K. Above this temperature, the surface energy is boosted and increases exponentially up to another factor of ~ 100 at about 1200 K [2].Exceeding temperatures of 1300 K, grain sizes microscopically change (increase) for all samples, leading to an instability of aggregates and therefore making growth challenging. Beyond 1400 K no classical collisional growth is possible. As consequence, there is a spatial region in protoplanetary disks with temperatures around 1200 K which favors aggregation and, therefore, will likely be a sweet spot for planetesimal formation as indicated in fig.1.[1] Bogdan, T., Pillich, C., Landers, J., Wende, H., & Wurm, G. (2020). Drifting inwards in protoplanetary discs I Sticking of chondritic dust at increasing temperatures. Astronomy & Astrophysics, 638, A151.[2] Pillich, C., Bogdan, T., Landers, J., Wurm, G., Wende, H. (2021). Drifting inwards in protoplanetary discs II The influence of water on sticking properties at increasing temperatures. Astronomy & Astrophysics, (accepted). 
Degradation of bacteria mass spectral signals via hydrothermal processing and UV irradiation: relevance to life detection on icy moons
Authors: Salter Tara , Waite Hunter , Sephton Mark
Published: July 2021

The inferred subsurface oceans of the icy moons of Jupiter and Saturn, in particular Europa and Enceladus, may contain conditions suitable for life. Plumes of material have been detected from Enceladus and may also be present on Europa. These plumes could contain molecular signs of habitability that could be detected by mass spectrometers on orbiting spacecrafts, such as the upcoming Europa Clipper mission. However, these molecular markers may have degraded between their production and detection, for example by possible hydrothermalism in the subsurface ocean or by UV irradiation once carried into space by the plume. It is important to look at how the biosignatures degrade under different conditions as degradation processes need to be taken into account when analysing the data from life detection missions. We investigate how these two processes affect the mass spectral signals of terrestrial bacteria.Two cyanobacteria samples, Spirulina and Chlorella, were subjected to hydrothermal processing and UV irradiation. Hydrous pyrolysis was used to simulate hydrothermal degradation. Experiments were carried out for 24 or 72 hours at temperatures between 200 and 300 °C. The pyrolyzed contents were subsequently extracted and analysed with gas chromatography-mass spectrometry (GC-MS). UV irradiation was carried out in a vacuum chamber (10-2 mbar), using a 300 W short arc xenon lamp at UV to near infrared wavelengths (~250 – 800 nm). After UV irradiation, samples were analysed using pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS).Our results show that hydrothermal processing of cyanobacteria affects the compound classes in different ways. Carbohydrate and protein components from the cyanobacteria were significantly affected, with phenol and indole derivatives detected. However, some of the biological fingerprint, such as straight-chain even numbered saturated fatty acids from lipid fragments, remain even at the harshest experimental conditions used in our study. This provides confidence that these diagnostic molecules could be used as fingerprints of biological materials on icy moons.
The May 26, 2020 multi-chord stellar occultation by the trans-Neptunian object (119951) 2002 KX14
Authors: Kretlow Mike , Ortiz José Luis , Sicardy Bruno , Desmars Josselin , Santos-Sanz Pablo , Morales Nicolás , Braga-Ribas Felipe , Vara-Lubiano Mónica , Rommel Flavia L. , Souami Damya , Duffard René , Alvarez-Candal Alvaro , Morgado Bruno , Fernández-Valenzuela Estela ,   2002 KX14 occultation collaboration
Published: July 2021

AbstractCentaurs and trans-Neptunian objects (TNOs) are considered to be the most pristine members of our solar system, beside Oort cloud objects.The observation of stellar occultations by solar system objects is a powerful technique to directly measure their size and profile shapes with kilometer accuracy [e.g. 1, and references therein], to probe the environment of them with the possibility to reveal satellites and / or rings [e.g. 2, 3] and to detect or to constrain an atmosphere down to the nanobar level [e.g. 4]. Finally it provides a high-accuracy astrometric measurement, which can for example be used for improving the prediction of subsequent occultation events within short or mid-term time spans.Here we report the observation of an occultation event of the star Gaia DR2 4111560308371475840 (G = 14.6 mag) by the TNO (119951) 2002 KX14 on May 26, 2020. The shadow was predicted to cross eastern Europe (Fig. 1) and the event was observed successfully by ten stations supplemented by another good dozen of stations which had a miss (no event detected).2002 KX14 is a low-inclination (i ~ 0.4°), low-eccentricity (e ~ 0.04) cold classical TNO, orbiting the Sun at an average distance of a ~ 39 au. The radiometric diameter is given as 455 ± 27 km [5]. On April 26, 2012, an occultation by this object was observed with the 4.2-m William Herschel Telescope on La Palma (Spain) at high cadence. From this single-chord observation (with a chord length of 415 ± 1 km), combined with accurate astrometry at the time of occultation, an area-equivalent diameter of at least 365 (+30, -21) km was estimated [6]. The rotational period is yet unknown. The lightcurve amplitude is reported as Δm 
Influence of time-variable solar wind on the response of Mercury’s magnetosphere
Authors: Aizawa Sae , André Nicolas , Modolo Ronan , Werner Elisabeth , Slavin Jim , Boardsen Scott , Leblanc Francois , Chaufray Jean-Yves , Raines Jim
Published: July 2021

BepiColombo is going to conduct its first Mercury flyby in October 2021. During this flyby,  plasma measurement will be obtained and bring new insights on the Hermean magnetosphere and its interaction with the Sun despite the limited field of view of the instruments during the cruise phase. Unlike Mariner-10 ion measurements will be obtained, and unlike MESSENGER, low energy electrons and ions will be measured simultaneously. In this study, we have revisited Mariner 10 and MESSENGER observations with the help of the global hybrid model LatHyS in order to understand the influence of time-variable solar wind and to constraint the plasma environment. We are able to reproduce the magnetic field observations of Mariner 10 along its trajectory with in particular two distinct signatures consisting of a quiet and disturbed state of the magnetosphere. In addition, the plasma spectrogram is also collected in the model and this enables us to detail the properties of the charged particles observed during the flyby. We will discuss all these signatures both in term of an interaction with a time-variable solar wind and localized processes occurring in the magnetosphere. We will then present the virtual sampling of both the magnetic field and plasma spectrogram along BepiColombo’s first Mercury flyby trajectory and discuss the possible signatures to be observed at that time.
Analysis of selected Solar events with Mars Express radio occultation data
Authors: Karatekin Özgür , Krishnan Ananya , Ebrahimkutty Nayeem , Henry Greg , El Fadhel Ahmed , Witasse Olivier
Published: July 2021

ESA’s Mars Express spacecraft has been exploring the red planet since January 2004. The spacecraft is able to receive and transmit signals at both S-band and X-band. Changes in the radio signals properties while propagating through the atmosphere yield information on the electron density profile. The Mars’ ionosphere is very variable in time. One source of its variability is the solar activity. Here we study the effect of solar flares and coronal mass ejections on the Mars’ ionosphere using the publicly available Mars Express radio occultation data. A new software in python was developed to process the residual frequencies data sets, and was validated using higher-level archival data. We calculate the electron density profiles before, during, and after such solar events. The variations in ionospheric parameters (total electron content, peak density and altitude) are quantified in order to understand the ionospheric changes due to solar activity. As expected, significant variations in these parameters have been identified. The results are compared with additional measurements and models.Figure 1: Electron density profiles observed by MEX on 2011 during 2 days following a solar event.
Twinkle: Update on the international, collaborative exoplanet survey
Authors: Edwards Billy , Tessenyi Marcell , Stotesbury Ian , Archer Richard , Joshua Max , Wilcock Ben
Published: July 2021

The Twinkle Space Mission is a space-based observatory that has been conceived to measure the atmospheric composition of exoplanets, stars and solar system objects. Twinkle’s collaborative multi-year global survey programmes will deliver visible and infrared spectroscopy of thousands of objects within and beyond our solar system, enabling participating scientists to produce world-leading research in planetary and exoplanetary science. Twinkle’s growing group of international Founding Members have now started shaping the survey science programme within focused Science Teams and Working Groups and will soon be delivering their first papers. Twinkle will have the capability to provide simultaneous broadband spectroscopic characterisation (0.5 - 4.5µm) of the atmospheres of several hundred bright exoplanets, covering a wide range of planetary types. It will also be capable of providing phase curves for hot, short-period planets around bright stars targets and of providing ultra-precise photometric light curves to accurately constrain orbital parameters, including ephemerides and TTVs/TDVs present in multi-planet systems.I will present an overview of Twinkle’s mission status and discuss some example exoplanet surveys to highlight the broad range of targets the mission could observe, demonstrating the scientific potential of the spacecraft. I will also report on the work of the Twinkle exoplanet Science Team, showcasing their science interests and the studies into Twinkle’s capabilities that they have conducted since joining the mission.
Vacuum ultraviolet photoabsorption spectroscopy of space-related ices
Authors: Ioppolo Sergio , Kanuchova Zuzana , James Rachel L. , Dawes Anita , Ryabov Alexei , Dezalay Jordan , Jones Nykola C. , Hoffmann Soren V. , Mason Nigel J. , Strazzulla Giovanni , Migliorini Alessandra , Tosi Federico , Piccioni Giuseppe , Barbieri Mauro
Published: July 2021

Ices are widely present in the cold regions across the Universe, for instance, in the interstellar medium as mantles on interstellar and circumstellar dust and on the surfaces of small bodies of the Solar System - beyond the distance around 3-5 AU known as the “snowline" (i.e. at temperatures below 150-170 K). The continuous energetic processing of icy objects in the Solar System induces physical and chemical changes within the ice. Laboratory experiments that simulate energetic processing (ions, photons, and electrons) of ices are therefore essential for interpreting and directing future astronomical observations. Here we provide vacuum ultraviolet (VUV) and UV-Vis photoabsorption spectroscopic data of pristine and energetically processed (electron irradiated) space-related ices. Experiments were performed using a custom-made Portable Astrochemistry Chamber (PAC), which has a base pressure of 10-9 mbar. Photoabsorption spectra of ices were measured at the AU-UV beam line of the ASTRID2 synchrotron light source at Aarhus University in Denmark (see Eden et al. 2006; Palmer et al. 2015). We present the results of three series of experiments: one dedicated to the study of nitrogen- and oxygen-rich ices (Ioppolo et al., 2020); the other one to the spectroscopic study of carbonic acid as formed and destroyed under conditions relevant to space (Ioppolo et al., 2021); and the third one to the study of photoabsorption spectra of O2 ice, both pure and mixed with other species (Migliorini et al, 2021). Results are discussed in light of their relevance to various astrophysical environments, e.g., the icy moons of Saturn and Jupiter. Laboratory VUV-UV-vis spectra of ices can help their future identification on the surface of icy objects in the Solar System by the upcoming Jupiter ICy moons Explorer mission and on interstellar dust by the James Webb Space Telescope spacecraft.This research was partly supported by the Italian Space Agency (Grant ASI-INAF n. 2018-25-HH-0).   REFERENCES:Eden, S., Limão-Vieira, P., Hoffmann, S. V., & Mason, N. J. 2006, Chem. Phys., 323, 313Ioppolo, S., Kanuchova Z., James, R.L., Dawes, A., Jones, N.C., Hoffmann, S.V., Mason, N.J., Strazzulla, G. 2020, Astron. Astrophys. 641, A154Ioppolo, S., Kanuchova Z., James, R.L., Dawes, A., Ryabov, A., Dezalay, J., Jones, N.C., Hoffmann, S.V., Mason, N.J., Strazzulla, G. 2021, Astron. Astrophys. 645, A172Migliorini, A., Kanuchova Z., Ioppolo, S., Jones, N.C., Hoffmann, S.V., Tosi, F., Piccioni, G., Barbieri, M. 2021, Icarus, submittedPalmer, M. H., Ridley, T., Hoffmann, S. V., et al. 2015, J. Chem. Phys., 142, 134302 
Twinkle: a low-Earth orbit, visible and infrared observatory for exoplanet and solar system spectroscopy
Authors: Edwards Billy , Tessenyi Marcell , Stotesbury Ian , Archer Richard , Wilcock Ben , Joshua Max
Published: July 2021

The Twinkle Space Mission is a space-based observatory that has been conceived to measure the atmospheric composition of exoplanets, stars and solar system objects. Twinkle’s collaborative multi-year global survey programmes will deliver visible and infrared spectroscopy of thousands of objects within and beyond our solar system, enabling participating scientists to produce world-leading research in planetary and exoplanetary science. Twinkle’s rapid pointing and non-sidereal tracking capabilities will enable the observation of a diverse array of Solar System objects, including asteroids and comets. Twinkle aims to provide a visible and near-infrared (0.5-4.5 micron) spectroscopic population study of asteroids and comets to study their surface composition and monitor activity. Its wavelength coverage and position above the atmosphere will make it particularly well-suited for studying hydration features that are obscured by telluric lines from the ground as well as searching for other spectral signatures such as organics, silicates and CO2.I will present an overview of Twinkle’s capabilities and discuss the broad range of targets the mission could observe, including the measurements it will take to support JAXA's Martian Moons eXploration (MMX) mission, demonstrating the broad scientific potential of the spacecraft.
Jupiter’s  Polar Vortices in the Mid-Infrared as Observed by Subaru/COMICS Prior to and During the Juno Mission
Authors: Orton Glenn , Sinclair James , Burke Angela , Fujiyoshi Takuya , Kasaba Yasumasa , Momary Thomas , Chan Ryan , Fletcher Leigh
Published: July 2021

MotivationRecent close-up views of Jupiter’s polar regions by NASA’s Juno spacecraft are providing a wealth of information about the dynamics and composition of Jupiter’s poles. We present thermal imaging observations from a series of repeated observations over fifteen years.  These images complement the observations made by the Juno spacecraft by observing in a spectral region not covered by its instrumentation, providing a near-global context for the narrow fields-of-view of Juno’s Microwave Radiometer and JunoCam instruments and providing a long term baseline to study Jovian atmospheric evolution. In this work, we specifically focus on the distinct thermal signatures of Jupiter’s northern and southern polar regions in both the troposphere and stratosphere. Although Cassini CIRS maps of Jupiter in 2000 could see this transition to coll polar vortices (e.g. Simon-Miler et al. 2006, Fletcher et al. 2016), the spatial resolution of the 8-m facility provides access to higher latitudes.DataWe present thermal imaging from the Subaru Telescope using the COoled Mid-Infrared Camera and Spectrometer (COMICS, Kataza et al., 2000), between 7.8 and 25 μm. These data map temperatures in the upper troposphere (100 – 500 mbar) and stratosphere (20 – 0.5 mbar), and they constrain the distribution of tropospheric gases and condensate aerosols. This data set covers 2005 to 2020, allowing for the investigation of long-term trends, as well as comparisons with Juno and Juno-supporting observations at other wavelengths from 2016 onward.   Preliminary ResultsFigure 1 illustrates the composite polar maps of brightness temperature for each hemisphere using images measured in January, 2017. The retrieved temperatures in each latitude circle were derived from these data were binned over  μ (= cosine of emission angle) and the centre-to-limb variation was inverted using the NEMESIS radiative transfer code (Irwin et al., 2008). The results demonstrated that tropospheric temperatures exhibit a steep decline of at least 2 K poleward of 60°N-63°N (planetocentric), which we believe marks the boundary of a tropospheric polar vortex. A similar drop in temperature takes place more gradually over 54°S-64°S. The precise latitude of the inferred vortex boundary varies slightly between observations in both hemispheres. No seasonal trends in these latitude variations were observed. Stratospheric polar temperatures are affected by auroral-related heating at 140° – 230°W (System III) at high-northern latitudes (>55°N) and 330° – 90°W at high-southern latitudes (
European Research Council (ERC) demographics and initiatives to promote diversity
Authors: Fivet Vanessa , Alves de Jesus-Rydin Claudia , Keil Andreas
Published: July 2021

The European Research Council (ERC), Europe’s premiere funding agency for frontier research, views equality of opportunities as an essential priority. The ERC monitors closely various demographic data yearly on every call and has taken actions to tackle imbalances and potential implicit and explicit biases.In this presentation, we will focus on demographic data of the three main funding schemes: Starting Grant, Consolidator Grant and Advanced Grant. The data of the ERC population, collected over the two past European Framework Programs (FP7 2007-2013 and H2020 2014-2020), will focus on gender and geographic location within the area of Universe Sciences and more particularly Planetary Sciences.The ERC is aware that promoting diversity is a continuous effort. We will present the various initiatives put in place since the inception of the ERC together with the recent actions taken to adapt to the COVID19 pandemic.
How atmospheric escape sculped the evolution of the Martian CO2 atmosphere over time
Authors: Scherf Manuel , Lichtenegger Herbert , Dyadechkin Sergey , Lammer Helmut , Adam Raven , Kallio Esa , Amerstorfer Ute , Järvinen Riku
Published: July 2021

Mars likely had a denser atmosphere during the Noachian eon about 3.6 to 4.0 billion years ago (Ga). How dense this atmosphere might have been, and which escape mechanisms dominated its loss are yet not entirely clear. However, non-thermal escape processes and potential sequestration into the ground are believed to be the main drivers for atmospheric loss from the present to about 4.1 Ga.To evaluate non-thermal escape over the last ~4.1 billion years, we simulated the ion escape of Mars' CO2 atmosphere caused by its dissociation products C and O atoms with numerical models of the upper atmosphere and its interaction with the solar wind (see Lichtenegger et al. 2021; https://arxiv.org/abs/2105.09789). We use the planetward-scattered pick-up ions for sputtering estimates of exospheric particles including 36Ar and 38Ar isotopes, and compare ion escape, with sputtering and photochemical escape rates. For solar EUV fluxes ≥3 times the present-day Sun (earlier than ~2.6 Ga) ion escape becomes the dominant atmospheric non-thermal loss process until thermal escape takes over during the pre-Noachian eon (earlier than ~4.0 - 4.1 Ga). If we extrapolate the total escape of CO2-related dissociation products back in time until ~4.1 Ga, we obtain a theoretical equivalent to CO2 partial pressure of more than ~3 bar, but this amount did not necessarily have to be present and represents a maximum that could have been lost to space within the last ~4.1 Ga.Argon isotopes can give an additional insight into the evolution of the Martian atmosphere. The fractionation of 36Ar/38Ar isotopes through sputtering and volcanic outgassing from its initial chondritic value of 5.3, as measured in the 4.1 billion years old Mars meteorite ALH 84001, until the present day can be reproduced for assumed CO2 partial pressures between ~0.2-3.0 bar, depending on the cessation time of the Martian dynamo (assumed between 3.6-4.0 Ga) - if atmospheric sputtering of Ar started afterwards. The later the dynamo ceased away, the lower the pressure could have been to reproduce 36Ar/38Ar.Prior to ~4.1 Ga (i.e., during the pre-Noachian eon), thermal escape should have been the most important driver of atmospheric escape at Mars, and together with non-thermal losses, might have prevented a stable and dense CO2 atmosphere during the first ~400 million years. Our results indicate that, while Mars could have been warm and wet at least sporadically between ~3.6-4.1 Ga, it likely has been cold and dry during the pre-Noachian eon (see also Scherf and Lammer 2021; https://arxiv.org/abs/2102.05976).
Exploration of the structure of giant planets with fast calculations and a bayesian approach
Authors: Howard Saburo , Guillot Tristan , Bazot Michaël , Miguel Yamila
Published: July 2021

AbstractThe Juno spacecraft is providing measurements of Jupiter's gravity field with an outstanding level of accuracy [3], leading to better constraints on the interior of Jupiter. Improving our knowledge of the internal structure of Jupiter is key, to understand the formation and the evolution of the planet [5,6] but also in the framework of exoplanets exploration. Hence, developing interiors models of Jupiter which are consistent with the observations is essential.Models of giant planets' internal structure are built with the code CEPAM [2] to compute the gravitational moments J2n [1] and compare them to the observational values. As the numerical calculation of the gravitational moments is crucial, we are here using a fast method based on a 4th order development of the Theory of Figures, coupled with the more precise CMS (Concentric MacLaurin Spheroid) method. This allows us to obtain reliable values of J2n in a reasonable amount of time.MCMC (Markov chain Monte Carlo) simulations are then run to study a wide range of interior models, using the above way to compute the gravitational moments. This bayesian approach leads to a broad investigation of the parameters range such as the chemical abundances, the 1 bar temperature or the transition pressure between the molecular hydrogen and metallic hydrogen layers.Important questions remain to be clarified like the distribution and amount of the heavy elements inside giant planets, following the hypothesis of a gradual distribution of the heavy elements up to a certain fraction of Jupiter's radius [7]. Throughout this talk, I will pay particular attention on the equations of state used in our models [4]. Indeed, giant planets' internal structure seems strongly linked to the physical properties of its components and it is critical to assess how sensitive to the equations of state our models are.References[1] Guillot, T., Miguel, Y. et al.: A suppression of differential rotation in Jupiter's deep interior, Nature, Vol 555, pp. 227-230, (2018).[2] Guillot, T. and Morel, P.: CEPAM: a code for modeling the interiors of giant planets, Astronomy and Astrophysics Supplement Series 109, 109-123 (1995)[3] Iess, L. et al.: Measurement of Jupiter's asymmetric gravity field, Nature, Vol 555, pp. 220-222, (2018).[4] Miguel, Y., Guillot, T. et al.: Jupiter internal structure: the effect of different equations of state. Astron. Astrophys. 596, A114 (2016)[5] Vazan, A., Helled, R. and Guillot, T.: Jupiter's evolution with primordial composition gradients. Astron. Astrophys. 610, L14 (2018).[6] Venturini, J., Helled, R.: Jupiter's heavy-element enrichment expected from formation models. Astron. Astrophys. 634, A31 (2020).[7] Wahl, S. M. et al.: Comparing Jupiter interior structure models to Juno gravity measurements and the role of a dilute core, Geophys. Res. Lett. Vol 44, pp. 4649-4659, (2017).
The solar wind between 0.1 and 1 AU: Parker Solar Probe - BepiColombo radial alignment and BepiColombo - ACE magnetic alignment
Authors: Alberti Tommaso , Milillo Anna , Heyner Daniel , Hadid Lina Z.
Published: July 2021

At the beginning of September 2020 ACE and BepiColombo spent several hours in an interesting magnetically connected configuration, while at the end of the same month Parker Solar Probe (PSP) and BepiColombo were radially aligned. Being PSP orbiting near 0.1 AU, BepiColombo near 0.6 AU, and ACE at 1 AU, these geometries are of particular interest for investigating the evolution of solar wind properties at different heliocentric distances by observing the same solar wind plasma parcels. In this contribution we use magnetic field observations from pairs of spacecraft to characterize both the topology of the magnetic field at different heliocentric distances (scalings and high-order statistics) and how it evolves when moving from near-Sun to far-Sun locations. We observe a breakdown of the statistical self-similar nature of the solar wind plasma due to an increase of the intermittency level when moving away from the Sun. These results support previous evidences on the radial dependence of solar wind scaling behavior and can open a novel framework for modeling magnetic field topological changes across the Heliosphere.
A new type of cloud discovered from Earth in the upper Martian atmosphere
Authors: Lilensten Jean , Dauvergne Jean-Luc , Pellier Christophe , Delcroix Marc , Beaudoin Emmanuel , Vincendon Mathieu , Kraaikamp Emil , Bertrand Guillaume , Foster Clyde , Go Christopher , Kardasis Μanos , Pace Alexei , Peach Damian , Wesley Anthony , Samara Evangelia , Poedts Stefaan , Colas Francois
Published: July 2021

During the 2020 Mars opposition, we observe from Earth the occurrence of a non-typical large-scale high-altitude clouds system, extending over thousands of km from the equator to 50°S. Over 3 hours, they emerge from the night side at an altitude of 90 (-15/+30) km and progressively dissipate in the dayside. They occur at a solar longitude of 316°, west of the magnetic anomaly and concomitantly to a regional dust storm. Despite their high altitude, they are composed of relatively large particles, suggesting a probable CO2 ice composition, although H2O cannot be totally excluded. Such ice clouds were not reported previously. We discuss the formation of this new type of clouds and suggest a possible nucleation from cosmic particle precipitation.
Dynamical evidence for Phobos and Deimos as remnants of a disrupted common progenitor
Authors: Bagheri Amirhossein , Khan Amir , Efroimsky Michael , Kruglyakov Mikhail , Giardini Domenico
Published: July 2021

The origin of the Martian moons, Phobos and Deimos, remains elusive. While the morphology and their cratered surfaces suggest an asteroidal origin, capture has been questioned because of potential dynamical difficulties in achieving the current near-circular, near-equatorial orbits. To circumvent this, in situ formation models have been proposed as alternatives. Yet, explaining the present location of the moons on opposite sides of the synchronous radius, their small sizes and apparent compositional differences with Mars has proved challenging. Here, we combine geophysical and tidal-evolution modelling of a Mars–satellite system to propose that Phobos and Deimos originated from disintegration of a common progenitor that was possibly formed in situ. We show that tidal dissipation within a Mars–satellite system, enhanced by the physical libration of the satellite, circularizes the post-disrupted eccentric orbits in
The PLATO mission: Overview and status
Authors: Rauer Heike , Pagano Isabella , Mas-Hesse Miguel , Aerts Conny , Deleuil Magali , Gizon Laurent , Goupil Marie-Jo , Heras Ana María , Piotto Giampaolo , Pollacco Don , Ragazzoni Roberto , Ramsay Gavin , Udry Stéphane
Published: July 2021

PLATO is an ESA mission dedicated to the study of exoplanets and stars, with a planned launch date in 2026. By performing photometric monitoring of about 250 000 bright stars (mV < 13), PLATO will be able to discover and characterise hundreds of exoplanets, including small planets orbiting up to the habitable zone of solar-like stars. PLATO’s precision will also allow for a precise characterisation of the host stars through asteroseismology. These objectives require both a wide field of view and high sensitivity, which are achieved with a payload comprising 24 cameras with partially overlapping fields of view. They are complemented by 2 more cameras optimised for brighter stars that will also be used as fine guidance sensor. The PLATO development phase started after the mission adoption in July 2017. The Mission Preliminary Design Review (PDR) was declared successful in October 2020. The implementation and delivery to ESA of the flight model CCDs for all cameras (4 CCDs per camera) has been completed. Currently the Structural Thermal Model (STM) of the payload optical bench is being manufactured, while the STM of a single camera has already been successfully tested. In parallel, a first engineering model of a complete, fully functional camera is being integrated, to verify its performance under operational conditions, and the qualification models of the different payload units are being built.We will present the status of the PLATO payload implementation in the context of the satellite development. In particular, we will describe the payload manufacturing, integration, and tests that will be reviewed at the Critical Milestone in the second half of 2021. We will also summarise the progress made in the science preparation activities, as well as on the ground segment.
Bedrock river erosion through dipping layered rocks: quantifying erodibility through kinematic wave speed
Authors: Mitchell Nate A. , Yanites Brian J.
Published: July 2021

Abstract. Landscape morphology reflects drivers such as tectonics
and climate but is also modulated by underlying rock properties. While
geomorphologists may attempt to quantify the influence of rock strength
through direct comparisons of landscape morphology and rock strength
metrics, recent work has shown that the contact migration resulting from the presence of mixed lithologies may hinder such an approach. Indeed, this work counterintuitively suggests that channel slopes within weaker units can sometimes be higher than channel slopes within stronger units. Here, we expand upon previous work with 1-D stream power numerical models in which we have created a system for quantifying contact migration over time. Although previous studies have developed theories for bedrock rivers incising through layered stratigraphy, we can now scrutinize these theories with contact migration rates measured in our models. Our results show that previously developed theory is generally robust and that contact migration rates reflect the pattern of kinematic wave speed across the profile. Furthermore, we have developed and tested a new approach for estimating kinematic wave speeds. This approach utilizes channel steepness, a known base-level fall rate, and contact dips. Importantly, we demonstrate how this new approach can be combined with previous work to estimate erodibility values. We demonstrate this approach by accurately estimating the erodibility values used in our numerical models. After this demonstration, we use our approach to estimate erodibility values for a stream near Hanksville, UT. Because we show in our numerical models that one can estimate the erodibility of the unit with lower steepness, the erodibilities we estimate for this stream in Utah are likely representative of mudstone and/or siltstone. The methods we have developed can be applied to streams with temporally constant base-level fall, opening new avenues of research within the field of geomorphology.
Comprehensive evaluation of hydrological drought and the effects of large reservoir on drought resistance in the Hun River basin, NE China
Authors: Yang Fengtian , Yue Shupeng , Sheng Xiaodan
Published: July 2021

Abstract. Evolution of drought under changing climate and the operation of large reservoir play an important role in drought warning and control. Thus, the evolution characteristics of hydrological drought and the effects of large reservoir on drought resistance are explored in the Hun river basin (HRB). Firstly, Standardized runoff Index (SRI) was adopted to evaluate the evolution characteristics of hydrological drought. Meanwhile, based on drought duration and severity identified by the run theory, the copula function with the highest goodness of fit was selected to calculate the return period of hydrological drought. Furthermore, the propagation time from meteorological to hydrological drought were determined by calculating the Pearson correlation coefficients between 1-month SRI and multi-time scale Standardized precipitation index (SPI). Finally, based on the cumulative precipitation deficit thresholds for triggering hydrological drought, the impact of large reservoir on drought resistance of the basin was revealed. The results show that: (1) hydrological drought showed a slight strengthening trend in the eastern, while presented alternate characteristics of drought and flood in the western and center of the HRB from 1967 to 2019; (2) the western and center of the HRB were vulnerable districts to hydrological drought with longer drought duration and higher severity; (3) the most severe drought with drought duration of 23 months, severity of 28.7, and corresponding return periods that both exceed the thresholds of duration and severity and exceed the threshold of duration or severity were 371 years and 89 years, respectively; (4) the propagation time from meteorological to hydrological drought of the lower reaches of large reservoir has been significantly prolonged owing to the operation of large reservoir; and (5) the operation of large reservoir strengthened the drought resistance in the lower reaches while lightly weaken in the upper reaches of large reservoir.
Into the unknown: Daniel Mendelsohn’s The Lost and the writing of third-generation Holocaust literature
Authors: Strakosch Antonia
Published: July 2021

As distance from the Holocaust increases, the crucial task of representing the genocide

in order to perpetuate its memory passes to later generations. In the past ten to fifteen

years, third-generation authors (defined here as the grandchildren of Holocaust

survivors) have emerged, according to Alan L. Berger, as ’the new bearers of Shoah

representation’ (2010a: 81). However, while the fields of psychology and, more

recently, epigenetics, have started examining the impact of inherited trauma on the

third generation, there is currently little scholarship on the distinct characteristics of

third-generation literature and the position from which it is written. Members of this

generation grapple with and seek to understand the unique dichotomy granted them at

birth. How can they reconcile their vague yet potent emotional connection to this

distant atrocity, and how might this impact their writing? To what extent can the third

generation reasonably claim to have inherited trauma from or postmemory of the

Holocaust? Which images and tropes might they use to convey the unsettling yet

generative tension at the heart of their experience: both the burden of their familial

inheritance, and the fact they are generationally removed and sheltered from the

atrocities of the Holocaust by their parents and grandparents? Through examining the

techniques third-generation author Daniel Mendelsohn uses in his memoir The Lost

(2006), this paper will trace a crucial link between the third generation’s complicated

traumatic inheritance and the narrative choices of their writing.