bluuebunny/crossref_metadata_2025 huggingface dataset:
Tides in the Jovian System
Authors: Jacobson Robert , Park Ryan
Published: September 2022

Tidal interaction is presumed to play a crucial role in the long term evolution
of the orbits of the Galilean satellites. Io's active volcanism and associated
heat flow are probably driven by tidal dissipation within the satellite. It is
of high interest to determine whether Io is spiraling toward or away from
Jupiter. If the former is true, Io is losing more energy through internal
dissipation than it is gaining from the torque on the tidal bulge that it raises
on Jupiter. Lainey et al. (2009 Nature 459, 957) published an investigation
of tidal effects in the Jovian system based on an analysis of astrometric
observations through 2007 and mutual events through 2003. Their modelling
included the tide raised on Jupiter by each Galilean satellite and the tide
raised on Io by Jupiter. Subsequently, we extended their analysis adding
additional astrometry through through 2013, mutual events through 2009, Galilean
satellite eclipse timings, and data acquired by the Voyager, Cassini, Galileo,
and New Horizons spacecraft (Jacobson and Folkner, 2014 AAS/Division for
Planetary Sciences Meeting Abstracts 46 418.03). With the inclusion of
the spacecraft data, we found that the tidal effects became barely dectectable
if at all.

On 2021 June 07 the Juno spacecraft flew by Ganymede at an altitude 1046 km.
Unlike our previous work, when we added the Juno tracking data to our data set
(also extended to astrometry through 2018 and mutual events in 2015), we were
able to obtain a strong determination of the dissipation, k2/Q (k2 is the love
number, Q is the tidal quality factor), of both Jupiter and Io. Our analysis
incorporated the Jupiter love number recently reported by Wahl et al. (2020 
Astrophys. J. 891, 42) from Juno tracking data. Our Jupiter Q falls within
the bounds postulated by Peale (1999 Ann. Review Astron. Astrophys. 37,
533). The heat flux computed with our k2/Q for the tide raised on Io is within
the estimated range based on the observed heat radiated by Io (McEwen et al.
2004, Jupiter, Cambridge Univ. Press, 281). As a consequence of the tidal
forces, our orbit for Io is spiraling inward confirming the significant internal
energy loss. Our orbit for Europa is also spiraling inward as it attempts to
maintain its orbital resonance with Io despite the tidal force acting on it from
Jupiter. Ganymede, on the other hand, is on an outward spiral, moving out of its
resonance with Europa. The tidal force appears to be too small to detectably
alter Callisto's orbit.
(65) Cybele is the smallest asteroid at hydrostatic equilibrium, why?
Authors: Marsset Michaël , Brož Miroslav , Vermersch Julie , Rambaux Nicolas , Ferrais Marin , Viikinkoski Matti , Hanuš Josef , Jehin Emmanuel , Podlewska-Gaca Edyta , Bartczak Przemyslaw , Dudziński Grzegorz , Carry Benoit , Vernazza Pierre
Published: September 2022

Context – Cybele asteroids constitute an appealing reservoir of primitive material genetically linked to the outer Solar system. The physical properties (size, shape) of the largest members can be directly measured with high-angular resolution imagers mounted on large (8-m class) telescopes.

Aim – We took advantage of the bright apparition of the most iconic member of the Cybele population, (65) Cybele, in July and August 2021 to acquire high angular resolution images and optical light curves of the asteroid that were used to analyze its shape, topography and bulk properties (volume, density).

Methods – Eight series of images were acquired with SPHERE+ZIMPOL on the Very Large Telescope (ESO Program ID 107.22QN.001; PI: Marsset) and combined with optical light curves to reconstruct the shape of the asteroid using the ADAM (Viikinkoski et al. 2015), MPCD (Capanna et al. 2013) and SAGE (Bartczak & Dudziński 2018) algorithms.

Results – We will present Cybele’s bulk properties, including its volume-equivalent diameter and average density, in the context of other low-albedo P-type asteroids. We will show that Cybele’s shape and rotation state are entirely compatible to those of a Maclaurin equilibrium figure, opening up the possibility that D≥260 km (M≥1.4x10^19 kg) small bodies from the outer Solar System formed at equilibrium. We will further present the results of N-body simulations used to explore whether the equilibrium shape of Cybele is the result of a large resetting impact (similarly to the case of Hygiea; Vernazza et al. 2020), or if it is primordial (i.e., the result of early internal heating due to the radioactive decay of short- and long-lived radionuclides).
From a Homogeneous Non-biochemical Soup to the Emergence of Fundamental Functions of Life, including Adaptation. Physics and Chemistry Working Together at micron scales
Authors: Perez-Mercader Juan
Published: September 2022

Experimental progress made during the last decade in dynamical self-assembly and its chemical implementation can be used to provide experimental examples of biochemistry-free autopoietic systems that emerge from homogeneous and isotropic solutions under selected environmental conditions. These simple emergent vesicular structures and systems self-assemble and, then in aqueous media, using conformational information, metabolize, self-reproduce, compete and evolve by adaptive or non-adaptive means. They also are chemo and phototactic. These systems can be implemented in the chemistry laboratory. They can be thought of as very primitive proto-cellular systems capable of evolving. Their information handling and metabolism use RAFT (Reversible Addition Fragmentation Transfer) polymerization chemistry, their reproduction is by sporular seeds and results from the combination of both environment induced degradation and hydrodynamic instability of the autonomously created amphiphiles and their metastable self-assembled membranes. Their evolution involves the adaptive interaction between environment, population and the feedback loops between the two highly selective chemistries that are combined in the system: “click chemistry” and (RAFT) polymerization induced self-assembly.
Isotopic ratios in Titan’s HCN and HC3N derived from Cassini/CIRS observations
Authors: Vinatier Sandrine , Mathé Christophe , Bézard Bruno , Jolly Antoine , Gautier Thomas
Published: September 2022

Molecular nitrogen (N2) and methane (CH4) are the two major gas of Titan’s atmosphere. Their dissociation in the upper atmosphere by photons and photo-electrons leads to a wealth of chemical reactions forming more complex molecules like nitriles and hydrocarbons, which subsequently combine to form Titan’s photochemical haze.

Isotopic ratios measured in N2 and CH4 are of particular interest to constrain the origin and evolution of Titan’s atmosphere. While the same isotopic ratios measured in photochemical species bring constraints on fractionation processes occurring through their formation and/or loss.      

We focus on the determination on the 14N/15N and the 12C/13C isotopic ratios in HCN and the 12C/13C ratio in HC3N by analyzing their thermal emission acquired by the Cassini Composite Infrared Spectrometer (CIRS) from 2004 to 2017 (from the northern winter to the northern summer).  We used the entire CIRS dataset acquired with a limb-geometry viewing at the highest spectral resolution (0.5 cm-1). This allows us to search for potential variations of these isotopic ratios with latitude or with season, which could help to identify potential fractionation processes. Our analysis incorporates the temperature and minor species volume mixing ratio profiles inferred previously by Mathé et al. (2020) from the same limb dataset. We will present our results regarding the isotopic ratios in HCN for all latitudes, while we will present the 12C/13C ratio in HC3N only at high latitudes, as this nitrile is not detected at mid- and low-latitudes.

References:
- Mathé et al., 2020. Seasonal changes in the middle atmosphere of Titan from Cassini/CIRS observations: Temperature and trace species abundance profiles from 2004 to 2017. Icarus 344,  id. 113547.

 
The Evolution of Volatile Carbon During Planet Formation
Authors: Schwarz Kamber
Published: September 2022

Planets are formed in protoplanetary disks of gas and dust around young stars. Where and when a planet forms determines its ultimate composition. However, our ability to determine exoplanet compositions from observations is extremely limited. To truly understand what planets are made of we must instead observe the planet-forming material in the natal disk. In this talk I will discuss recent Atacama Large Millimeter/submilliter Array observations of molecular line emission which reveal low abundances of gas phase carbon in protoplanetary disks. This volatile sequestration, i.e., the removal of molecules such as CO from the gas, can occur via chemical reprocessing into less volatile species or trapping as ice in large dust grains or planetesimals. Using disk chemical modeling, I will demonstrate that under most physical conditions both chemical and physical processes likely play a role in removing carbon from the gas on short timescales. I will then present ways to test various predictions regarding mechanisms to remove gas phase carbon and  determine the dominate volatile carbon reservoir in planet-forming disks.
Reflection and Refraction of the L-O Mode 5 kHz Saturn Narrowband Emission by the Magnetosheath 
Authors: Wu Siyuan , Ye Shengyi , Fischer Georg , Jackman Caitriona , Wang Jian , Menietti John , Cecconi Baptiste , Long Minyi
Published: September 2022

The reflection-by-sheath mechanism of 5 kHz narrowband emissions (NB) at Saturn is confirmed by Cassini observations during several crossings of the magnetopause, which show that the 5 kHz NB can be prevented from escaping Saturn's magnetosphere. The L-O mode 5 kHz NB remained visible in areas of low plasma density but disappeared in regions of high plasma density. In three cases, NB disappeared immediately after the crossings of Saturn's magnetopause. A possible reflected NB event observed near the magnetosheath is discussed. This mechanism can help explain the 5 kHz NB observed at low latitudes outside the Enceladus plasma torus and their upper frequency limit variations. This mechanism significantly improves the current understanding of the 5 kHz NB.
Morphological reconstruction of a multiple detected coronal mass ejection
Authors: Amerstorfer Tanja , Bauer Maike , Möstl Christian , Barnard Luke , Riley Pete , Weiss Andreas J. , Reiss Martin A.
Published: September 2022

The CME event from October 2021 was in situ detected by BepiColombo, Solar Orbiter, DSCOVR and STEREO-A, whose Heliospheric Imagers (HI) additionally observed the event remotely. The latter observations are used to model the evolution of the CME through the inner heliosphere using the CME propagation model ELlipse Evolution based on HI (ELEvoHI). ELEvoHI assumes a drag-based interaction of the CME-sheath with the solar wind and allows it to deform according to local drag regimes. The ambient solar wind is provided by the time-dependent HelioMAS/HUXt model. Using the detected arrivals at the four different spacecraft we assess the ability of ELEvoHI to model the evolution of the shape of this CME.
Measuring Mercury Exosphere with the Mass Spectrometer Strofio
Authors: Livi Stefano , Allegrini Frederic , Schroeder Jared , Ho George
Published: September 2022

The mass spectrometer Strofio onboard BepiColombo will perform detailed measurements of the chemical composition of Mercury's exosphere. The time and spatial variations of the composition signal will deliver important information about the mechanisms responsible for creating and maintaining the exosphere. Data available from MESSENGER and ground telescope observations as well as simulation on the processes leading to the exosphere are compared to instrument performance as measured during calibration to prove Strofio can reach the stated goals.

The instrument suffered in flight an unexpected high voltage problem, but we were able to identify workarounds that should be sufficient to recover most (if not all) the performances necessary for achieving the goals of the experiment. 
Increasing the Signal-to-Noise Ratio of a Mass Spectrometer Using a Velocity Filter
Authors: Schroeder Jared , Livi Stefano , Allegrini Frederic , Wurz Peter
Published: September 2022

Strofio is a mass spectrometer, aboard the BepiColombo mission, that utilizes a time-of-flight method to determine the mass-per-charge of each particle entering its aperture in order to study the chemical composition of the exosphere of Mercury. Optimization of Strofio involves finding a balance between system efficiency and mass resolution while increasing the signal-to-noise ratio. In order to ensure our data is exospheric in nature, we must separate the Mercury environment from the background environment. The background environment is made up of thermal particles produced from sources like the outgassing of the spacecraft as well as from the instrument itself. This problem can be addressed by assigning the correct voltages to the source apparatus, thereby realizing a background filter. This filter works best in Mach 2 or larger regimes to ensure the targeted particles do not get filtered out with the background. My work focuses on writing and running a series of computer simulations that optimize the velocity filter in accordance with the configuration of the flight model.
JSON Implementation of Time-Frequency Radio Catalogues: TFCat
Authors: Cecconi Baptiste , Bonnin Xavier , Loh Alan , Louis Corentin , Taylor Mark
Published: September 2022

In the low frequency domain, the electromagnetic signatures are tracers of energetic and unstable particle populations rather than atomic and molecular transitions. Such signatures are identified with their spectral-temporal shape in time varying spectrograms. Figure 1 shows a spectrogram including Solar radio bursts (related to energetic electron beams escaping from the Sun) and terrestrial auroral kilometric radiation (related to the magnetospheric activity), observed by the Cassini/RPWS instrument during its flyby of the Earth.

 

Figure 1: Low frequency radio spectrogram (Wind/Waves) with solar and terrestrial natural radio emissions.

 

A corpus of catalogues identifying and documenting such radio signatures have been published since the 70's, but there was no standard exchange format, leading to difficulties in sharing and reusing such catalogues. 

 

TFCat (Time-Frequency Catalogue) is a data interchange format based on JSON. It defines several types of JSON objects and the manner in which they are combined to represent data about time-frequency features of a time spectrogram (a.k.a. dynamic spectrum), their properties, and their temporal and spectral extents. This implementation is inheriting from the GeoJSON file format [RFC7946].

 

In the past two years, several catalogues have been published using the TFCat format, and tools are now implementing interfaces on top of this specification, for labelling observations, displaying catalogues, or even using the catalogue shapes to select and process observational data. 

 

The Europlanet-2024 Research Infrastructure project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 871149.
The PLATO Mission
Authors: Rauer Heike , Aerts Conny , Deleuil Magali , Gizon Laurent , Goupil MarieJo , Heras Ana , Mas-Hesse Miguel , Pagano Isabella , Piotto Giampaolo , Pollacco Don , Ragazzoni Roberto , Ramsay Gavin , Udry Stephane
Published: September 2022

PLATO (PLAnetary Transits and Oscillations of stars) is ESA’s M3 mission and designed to detect and characterize extrasolar planets by high-precision, long-term photometric and asteroseismic monitoring of a large number of stars. PLATO will detect small planets around bright stars, including terrestrial planets in the habitable zone of solar-like stars. With the complement of radial velocity observation from ground, planets will be characterized for their radius, mass, and age with high accuracy. PLATO will provide us the first large-scale catalogue of well-characterized small planets up to intermediate orbital periods, relevant for a meaningful comparison to planet formation theories and to better understand planet evolution. It will make possible comparative exoplanetology to place our solar system planets in a broader context. PLATO will study host stars using asteroseismology, allowing us to determine the stellar properties with high accuracy, substantially enhancing our knowledge of stellar structure and evolution.

PLATO is scheduled for a launch date end 2026. Following the successful Critical Milestone Review, ESA has given green light for the implementation of the spacecraft and the payload, which includes the serial production of its 26 cameras. This presentation will give an overview of the PLATO science goals, of its instrument and mission profile status.
First results of super-resolution mapping of Enceladus’ surface, based on new navigation and photometric correction function
Authors: Ntinos Christos , Rodriguez Sebastien , Altobelli Nicolas , Le Mouelic Stephane , Robidel Rozenn , Seignovert Benoit , Tobie Gabriel , Cornet Thomas , Vallat Claire
Published: September 2022

The main objective of this research project is to develop super-resolution mapping methods to increase the spatial resolution of surface maps of icy moons of the Solar System by combining all the overlapping observations acquired during a given planetary mission. Cassini-Huygens was the first dedicated mission to Saturn, where it spent 13 years studying the gas giant and its system of moons and rings creating a treasure-trove of data. The focus of this study is to create global surface cartographic products in the infrared by evaluating the Cassini’s Visual and Infrared Mapping Spectrometer (VIMS) hyperspectral dataset in its entirety. We will first focus our efforts on developing, testing and validating the methods on Enceladus, a prime astrobiological candidate, which, in contrast to Titan, does not require any atmospheric corrections. We offer a new module in Python for creating the navigation cubes necessary in merging individual cubes into global mosaics, increasing the accuracy of the covered area and maximising the number of pixels used (e.g. limb-crossing pixels). Moreover, this new module, allows us to explore the Enceladus VIMS dataset in its entirety. We then determine a surface photometric function which mitigates variations in the brightness due to the changing geometric conditions of the flybys. With a precise and comprehensive navigation and an accurate surface photometric correction, we can apply the super-resolution method and present some preliminary maps with enhanced spatial resolution and signal-to-noise ratio.
Detection and Handling of Noise in Laser Altimetry Data: a Prerequisite for Tides Derivation
Authors: Stenzel Oliver , Hilchenbach Martin
Published: September 2022

The ESA/Jaxa mission BepiColombo[1] to Mercury will arrive in orbit in 2025. Onboard is the BepiColombo Laser Altimeter (BELA)[2], which will be used to scan the planetary surface. We plan on using these data to derive the tidal parameter h2[3]. To achieve an accurate result it is necessary to identify and eliminate noise in the laser altimeter records[4]. We present a strategy to find[5], [6] and neutralize the non-Gaussian noise contributions which contribute the most to the uncertainty in the derived Love number.

 References

[1] J. Benkhoff et al., ‘BepiColombo—Comprehensive exploration of Mercury: Mission overview and science goals’, Planet. Space Sci., vol. 58, no. 1, pp. 2–20, Jan. 2010, doi: 10.1016/j.pss.2009.09.020.

[2] N. Thomas et al., ‘The BepiColombo Laser Altimeter’, Space Sci. Rev., vol. 217, no. 1, p. 25, Feb. 2021, doi: 10.1007/s11214-021-00794-y.

[3] R. N. Thor et al., ‘Prospects for measuring Mercury’s tidal Love number h2 with the BepiColombo Laser Altimeter’, Astron. Astrophys., vol. 633, p. A85, Jan. 2020, doi: 10.1051/0004-6361/201936517.

[4] O. J. Stenzel, I. Hall, and M. Hilchenbach, ‘Mercury Tide Parameter Estimation from Laser Altimeter Records’, LPI contributions vol. 2678, p. 1990, Mar. 2022.

[5] O. Stenzel and M. Hilchenbach, ‘Towards machine learning assisted error identification in orbital laser altimetry for tides derivation’, pp. EPSC2021-688, Sep. 2021, doi: 10.5194/espc2021-688.

[6] O. Stenzel, R. Thor, and M. Hilchenbach, ‘Error identification in orbital laser altimeter data by machine learning’, pp. EGU21-14749, Apr. 2021, doi: 10.5194/egusphere-egu21-14749.
A CHEWIE first bite: the transmission spectrum of WASP-69b
Authors: Petit dit de la Roche Dominique , Lendl Monika
Published: September 2022

The CHEWIE survey (Clouds, Hazes and Elements vieWed on giant Exoplanets) aims to study the impact of the stellar environment on planet atmospheres and their aerosols at the day-night terminator through transmission spectra of planets in the Jupiter to Neptune mass range. It does this with ground-based, medium resolution observations between 330nm and 1100nm with the FORS2 instrument on the VLT. Our coverage of the optical wavelengths is complementary to upcoming JWST infrared observations. In this talk we present the first transmission spectrum of the survey, that of WASP-69b, a warm Saturn-mass planet with a puffed up atmosphere. We find that the spectrum shows the presence of aerosols and possible signs of sodium in the atmosphere, which is consistent with previous observations.
Constraining planet formation with atmospheric observations from the V1298 Tau planet system
Authors: Barat Saugata , Desert Jean-Michel
Published: September 2022

Theories of planet formation like core accretion mechanism  have been successful over the years in explaining the formation gas giant planets and even Neptune sized planets.  However, there are several open questions in the field of planet formation like the entropy of formation and its subsequent impact on the accretion process. Young planetary atmospheres that are freshly baked products of planet formation provide opportunities to test and constrain planet formation theories. Several such young planets like HR 8799 planets have been observed using direct imaging techniques.

This presentation focuses on the V1298 Tau system, which host multiple transiting planets and is estimated to be 23 Myr old, thus comparable to the HR 8799 planets. In this work we present transit observations of this system, including with HST/WFC3, and the interpretation of transmission spectra obtained for these planets using various atmospheric models.

Using these measurements, we explore different formation pathways for this planet system and present our findings in the context of mature planets as well as young directly imaged planets which have similar age but may have experience different formation and evolution pathways.
The Twinkle Space Mission's Extrasolar Survey
Authors: Edwards Billy , Wilcock Ben , Joshua Max , Tessenyi Marcell , Stotesbury Ian , Archer Richard , Barrathwaj Raman Mohan Yoga
Published: September 2022

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. The satellite is based on a high-heritage platform and will carry a 0.45 m telescope with a visible and infrared spectrograph providing simultaneous wavelength coverage from 0.5 - 4.5 μm. The spacecraft will be launched into a Sun-synchronous low-Earth polar orbit and will operate in this highly stable thermal environment for a baseline lifetime of seven years.

Twinkle will have the capability to provide high-quality infrared spectroscopic characterisation of the atmospheres several hundred bright exoplanets, covering a wide range of planetary types. Additionally, ultra-precise photometric light curves will accurately constrain orbital parameters, including ephemerides and TTVs/TDVs present in multi-planet systems.

Twinkle is available for researchers around the globe in two ways:

1) joining its collaborative multi-year survey programmes, which will observe hundreds of exoplanets and thousands of solar system objects; and

2) accessing dedicated telescope time on the spacecraft, which they can schedule for any combination of science cases.

I will present an overview of Twinkle’s capabilities and discuss the broad range of targets the mission could observe, demonstrating the huge scientific potential of the spacecraft. Furthermore, I will highlight the work of the Science Team of the Twinkle exoplanet survey, showcasing their science interests and the studies into Twinkle’s capabilities that they have conducted since joining the mission. Finally, I will discuss ongoing, and upcoming, early career programmes related to the Twinkle mission.
Educational Resources for EPN24 Planetary Field Analogue Sites
Authors: Thompson Tony , Cane Rosie
Published: September 2022

 

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 24 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)

Puna Plateau (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 PFA’s could affect the habitability of Mars.

 

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 which are currently in production are the creation of similar resources based around the habitability of the icy moons of the Solar System.

 

References: [1] The Europlanet Society, TA1 Planetary Field Analogues (PFA). Available at: https://www.europlanet-society.org/europlanet-2024-ri/ta1-pfa. [2] Salimpour, S., Bartlett, S., Fitzgerald, M.T. et al. The Gateway Science: a Review of Astronomy in the OECD School Curricula, Including China and South Africa. Res Sci Educ (2020). https://doi.org/10.1007/s11165-020-09922-0

 

Acknowledgement: Europlanet 2024 RI has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 871149.
CHEOPS Geometric albedo measurements of benchmark hot Jupiters
Authors: Krenn Andreas , Lendl Monika , Brandeker Alexis
Published: September 2022

By measuring the geometric albedo of a planet, the reflectivity of its atmosphere can be determined. This constitutes a vital piece of information when trying to characterise the nature of the planetary atmosphere. The albedo of a planet can be determined by measuring the drop in observed stellar flux when the planet is occulted by its host star during secondary eclipse.

We present observations of secondary eclipses of the gas giants HD189733b and HD209458b at optical wavelengths performed by the Characterising Exoplanets Satellite (CHEOPS). As both planets have moderate temperatures, the thermal contribution to their eclipse depth in the optical is small, making our observations uniquely sensitive to the reflectivity of the planetary atmospheres. Our data thus allow precise measurements of the planets’ geometric albedos, which we will present here. We will further discuss our findings and their implications in terms of the planetary atmospheric composition and the possible presence of aerosols. Finally, we compare our results with those of similar studies and discuss the implications of our findings in the context of future observations characterising gas giant atmospheres. 
An orbital stability-driven approach for the refinement of multi-planet systems’ architectures
Authors: Stalport Manu , Delisle Jean-Baptiste , Udry Stéphane , Matthews Elisabeth , Bourrier Vincent , Leleu Adrien
Published: September 2022

The formation and evolution of planetary systems has been, and remains, one of the big questions of Science. With more than 800 multi-planet systems discovered so far, as many outcomes of these formation and evolution processes are in reach of characterization. These represent precious pieces of the big puzzle. In order to obtain the most from these constraints, a precise knowledge of each system's architecture is crucial: it is key to identify the leading processes in shaping those systems, and hence relate their present state to their formation stage.

 

In this presentation, I will introduce a technique aiming at refining the planetary orbital parameters and masses (Stalport et al. 2022). This technique uses orbital stability arguments on top of a bayesian approach for the parameters' estimation. The estimation of orbital stability is based on short N-body numerical integrations together with the Numerical Analysis of Fundamental Frequencies (NAFF) fast chaos indicator (Laskar 1990), for which we propose a calibration strategy to scale chaos. The stability information is finally included a posteriori in the planetary parameters' posterior through importance sampling, after which new distributions of stable-only solutions are built.

This stability-driven refinement technique can be applied on any type of multi-planet systems, and notably in the context of planets in binaries. Besides the advantage of reducing the uncertainties on the dynamical parameters (orbital elements and planetary masses), such an approach can also provide additional insights into the dynamical states of the studied systems. I will present the revision of a few multi-planet systems in light of our approach, and particularly, I will describe a comprehensive dynamical analysis of the Kepler-444 planetary system (Stalport et al. submitted to A&A).

 

Approaches such as the one presented here are timely. They represent a way of getting the best constraints on planetary systems' architectures within limited observational datasets. I will stress for the importance of carrying a systematic revision of multi-planet systems under the loop of orbital stability. 
Upper limits of PH3 in the Venus atmosphere from mm spectra observed with the IRAM-30m telescope
Authors: Moreno Raphael , Lellouch Emmanuel , Kramer Carsten , Paubert Gabriel , Sanchez Miguel
Published: September 2022

Knowing the controversy  about the presence (or not)  of phosphine (PH3)  on Venus’ atmosphere, we have obtained spectra  of Venus  in the millimeter domain to constrain PH3 with new measurements.

Our observations -performed on Nov. 09th, 11th and 16th  2020- used the IRAM-30m single dish telescope located in Granada, Spain. to search in Venus’ atmosphere for the PH3(1-0) rotational lines at 266.944 GHz, and  the CO(2-1) and  13CO(2-1)   lines at 230.538 and 220.398 GHz, respectively. These disk-averaged measurements were obtained with  an  angular resolution of ~10” (HPBW)  while  Venus’ angular  diameter was ~12.5”.

These measurements have not  shown any PH3 spectral  signature, while the CO and  13CO lines were detected as expected.

We will present the data analysis of these observations, and use radiative transfer modelling to constrain the abundance upper limits  of PH3, and other minor species (HDO, SO and SO2)  present in our spectra.
Microphysical modeling of mixed composition ices in Titan’s stratosphere
Authors: Barth Erika L.
Published: September 2022

Titan’s atmosphere includes many trace hydrocarbon and nitrile species that reach their condensation temperatures in the stratosphere. These, for the most part, will condense out as ices given sufficient condensation nuclei, which are provided by the organic haze particles. Barth (2017) explored the physics behind the size and abundance of pure ice particles that could be present in Titan’s atmosphere and found they would condense out in layers between about 80 and 60 km given thermal conditions at the Huygens landing site (Fig. 1).

We now expand that study to multiple latitudes and include mixtures of trace species in the ice particles. Anderson et al. (2018) have shown that in Titan’s stratosphere, where many of the trace gases are saturated at the same altitude, they are likely co-condensing onto the haze particles. This changes the optical properties of the particles, but microphysically the formation process is similar to modeling the pure ices, as long as the vapor pressures are adjusted for the mixture.

Modeling is done using the Community and Aerosol Radiation Model for Atmospheres (CARMA; Barth 2020). CARMA models the physics of vertical transport and coagulation in a column of atmosphere and the interaction of particles and gases through nucleation, condensation, and evaporation. The growth routines have been modified to include particles composed of multiple volatiles, with each volatile component growing or evaporating in response to the environment (Barth & Toon, 2006). Particles are represented by a number of discrete mass bins, such that the size distribution of ice particles can be explored at all altitudes in the column. The model keeps track of the changes with time of the number of particles (including core mass for clouds) and mass density of volatiles.

This work is supported by NASA CDAP 80NSSC20K0485.

References: Anderson, C. M., R. E. Samuelson and D. Nna-Mvondo 2018. Organic ices in Titan’s stratosphere. Space Sci. Rev. 214, 125; Barth, E.L. 2020. PlanetCARMA: A New Framework for Studying Planetary Atmospheres. Atmosphere, 11(10), 1064; Barth, E. L. 2017. Modeling survey of ices in Titan’s stratosphere. Planet. Space Sci. 137, 20–31; Barth, E. L., and O. B. Toon 2006. Methane, ethane, and mixed clouds in Titan’s atmosphere: Properties derived from microphysical modeling. Icarus 182, 230–250.
Chemical composition analysis of Titan’s equatorial and midlatitude surface regions
Authors: Solomonidou Anezina , Schoenfeld Ashley , Malaska Michael , lopes Rosaly , Coustenis Athena , Birch Sam , Le Gall Alice , Schmitt Bernard
Published: September 2022

The Cassini cameras and especially the Visual and infrared Mapping Spectrometer has provided a sequence of spectra showing the diversity of Titan’s surface spectrum from flybys performed during the 13 years of Cassini’s operation. The investigation of Titan’s surface chemical composition is of great importance for the understanding of the atmosphere-surface-interior system of the moon. The Soi crater region with the well-preserved Soi crater in its center, spans from Titan’s equatorial regions to high northern latitudes. This provides a rich diversity of landscapes, one that is also representative of the diversity encountered across Titan. We mapped this region at 1:800,000 scale using Cassini SAR and non-SAR data and produced a geomorphological map using the methodology presented by [1] and [2]. The VIMS coverage of the region allowed for detailed analysis of spectra of 262 different locations using a radiative transfer technique [3;4] and a mixing model [5;6], yielding compositional constraints on Titan’s optical surface layer. Additional constraints on composition on the near-surface substrate were obtained from microwave emissivity. We identified 22 geomorphological units, 3 of which were not previously described, and derived combinations of top surface materials between dark materials, tholin-like materials, water-ice, and methane. We found no evidence of CO2 and NH3 ice. We also observe empty lakes as far south as 40°N, which mark the most southern extent of Titan’s north polar lakes. We use the stratigraphic relations between our mapping units and the relation between the geomorphology and the composition of the surface layers to build hypotheses on the origin and evolution of the regional geology.

[1] Malaska, M., et al. (2016), Icarus 270, 130; [2] Schoenfeld, A., et al. (2021), Icarus 366, 114516; [3] Solomonidou, A., et al. (2014), J. Geophys. Res. Planets, 119, 1729; [4] Solomonidou, A., et al. (2016), Icarus, 270, 85; [5] Solomonidou, A., et al. (2018), J. Geophys. Res. Planets, 123, 489; [6] Solomonidou, A., et al. (2020), A&A 641, A16.
Investigating the outer regions of the heliosphere with measurements and simulations of interstellar dust
Authors: Baalmann Lennart Robin , Hunziker Silvan , Strub Peter , Malaspina David , Schroffenegger Urs , Krüger Harald , Hervig Mark , Jaynes Allison N. , Kurth William , Wilson III Lynn B. , Sterken Veerle J.
Published: September 2022

Interstellar dust has been and will be measured by many spacecraft, both directly (e.g. by Cassini, Ulysses, DESTINY+, IMAP) and indirectly (e.g. by Voyager, Wind). The flux of interstellar dust at these spacecraft can be enhanced, in particular for small dust grains (<0.3µm), due to the so-called focusing phase of the solar cycle (for dust), in the early 2030s.

Through their surface charges, these small particles are coupled to the solar-cycle-dependent magnetic fields inside and to interstellar fields outside of the heliosphere. By comparing the measurements to simulations of interstellar dust, inferences about the outer regions of the heliosphere and its boundary can be made. The quality of these inferences highly depends on the availability of detailed measurements of interstellar dust, highlighting the necessity of a space-based dust detector operating during the upcoming focusing phase, such as the proposed DOLPHIN mission.

In this talk we give an overview of measurements and simulations of the measurements of various missions so far, and their link to interstellar dust simulations. 
Determination of the ice composition near the surface of comet 67P/Churyumov-Gerasimenko
Authors: Läuter Matthias , Kramer Tobias , Rubin Martin , Altwegg Kathrin
Published: September 2022

During the apparition of comet 67P/Churyumov-Gerasimenko (67P/C-G) solar irradiation causes varying rates for sublimation of volatile species from the cometary nucleus. Because sublimation processes take place close to the cometary surface, the relative abundance of volatiles in the coma and the ice composition are related to each other. To quantify this relation we assume a model for the expansion of a collisionless gas from the surface into the surrounding space. We use an inverse model approach to relate the in situ measurements of gas densities from the two Rosetta instruments COPS (COmet Pressure Sensor) and DFMS (Double Focusing Mass Spectrometer) at the positions of the spacecraft to the locations of surface gas emissions during the Rosetta mission 2014-2016. We assume the temporally integrated gas emissions to be representative for the ice composition close to the surface. Our analysis shows characteristic differences in the ice compositions between both hemispheres of 67P/C-G. In particular CO2 ice has a reduced abundance on the northern hemisphere. In contrast to the hemispherical differences, the two lobes do not show significant differences in terms of their ice composition.
Reprocessing Apollo seismic data
Authors: Zhang Xiang , Lognonné Philippe , Kawamura Taichi , Samuel Henri , Xu Zongbo , Sainton Grégory , Froment Marouchka , Onodera Keisuke
Published: September 2022

The Apollo Passive Seismic Experiments recorded more than 13000 events on the Moon during 1969-1977 [1]. However, not all of these events were used in our previous studies on the Moon due to the degradation of the quality of the recorded data (Figure 1A). To make better use of Apollo seismic data, we propose several new methods to reprocess it. First, since Apollo seismic records sometimes contain invalid data in every station and component (including the short period component), we removed these invalid data from raw Apollo records using time and ground station number. Then we removed several special spikes with the help of amplitude histogram. This enables us to compute the envelopes for a larger number of moonquake events. Acceleration and displacement step responses are used to fit glitches using the Lagrange multiplier method. The ‘glitches’ we term here are artifact one-sided pulses in the raw data. We find that the instrument response parameters vary with time. So, we determined the instrument response parameters with the calibration signal and removed it near the event. Finally, we used the smoothed envelope to detect the single spike (spike with only one point) and removed it when exceeds the envelope. These new processing steps lead to considerably cleaner Apollo data (Figure 1B), yield a more accurate arrival time reading, and result in an envelope that reflects more realistic waveform characteristics. We expect that additional moonquake records will become available with these methods for future research. Further study of the instrument response variations of the Apollo seismometer will also provide a reference for the new lunar seismometers to be deployed in upcoming space missions.

Figure 1. An example of a comparison plot before (A) and after (B) Apollo moonquake data processing.

Reference:

[1] Nunn, C., Garcia, R. F., Nakamura, Y., Marusiak, A. G., Kawamura, T., Sun, D., et al. (2020), Lunar seismology: A data and instrumentation review. Space Science Reviews, 216(5), 89. doi:10.1007/s11214-020-00709-3
Radio Sounding of the Venusian Atmosphere and Ionosphere with EnVision
Authors: Tellmann Silvia , Oschlisniok Janusz , Pätzold Martin , Dumoulin Caroline , Rosenblatt Pascal
Published: September 2022

EnVision has been selected in the M5 call of ESA’s Cosmic Vision program as the next European led mission to Venus. It is dedicated to unravel some of the numerous open questions about Venus' past, current state and future and will help to understand why Venus and Earth evolved so differently.

The Radio Science Experiment (RSE) on EnVision will perform extensive studies of the gravitational field but also Radio Occultations to sense the Venus atmosphere and ionosphere at a high vertical resolution of only a few hundred metres. These radio occultations provide electron density profiles in the ionosphere and atmospheric density, temperature and pressure profiles in the upper troposphere and mesosphere (~40 – 90 km). Additionally, they allow to study the H2SO4 absorption in the Venus cloud layer.

The first radio occultation experiment at Venus was conducted during the Mariner 5 flyby in 1967, followed by Mariner 10, several Venera missions, Magellan, and the Pioneer Venus Orbiter, and Akatsuki. The most extensive radio occultation study of the Venus atmosphere so far was carried out by the VeRa experiment on Venus Express.

EnVision will use two coherent frequencies (X- and Ka-band) to separate dispersive and nondispersive effects. This allows to distinguish between ionospheric wave structures and other noise induced effects in the ionosphere.

The use of Ka-band, which has never been used to sense the Venus atmosphere before, allows to study the H2SO4 absorption in the Venus cloud layer due to its high sensitivity to sulfuric acid absorption. Ka-band is also sensitive to liquid H2SO4 which provides the opportunity (in combination with X-band) to distinguish between gaseous and liquid H2SO4 absorption features on Venus for the very first time.

The short orbital period of EnVision in combination with its very small orbital inclination allows to cover all latitudes, longitudes, local times and solar zenith angles on Venus. Especially short-term variations caused by atmospheric waves can be identified to study traveling or stationary small scale atmospheric structures.
Dynamical evolution of basaltic asteroids outside the dynamical Vesta family
Authors: Troianskyi Volodymyr , Kankiewicz Pawel , Oszkiewicz Dagmara
Published: September 2022

Basaltic V-type asteroids are the leftovers from the formation and evolution of the differentiated planetesimals. They are thought to originate from mantles of multiple different parent bodies. Identifying the links between individual V-type asteroids and multiple planetesimals is challenging, especially in the inner part of the Main Asteroid Belt where the majority of V-type asteroid is expected to originate from a fossil planetesimal (4) Vesta.

We perform a 2Gy numerical integration of orbits of the selected V-type asteroids. For each asteroid we use 1001 clones to estimate the orbital uncertainties. In the integration we use information on physical properties of the considered V-type asteroids such as pole orientation, rotational period and thermal parameters. This may confirm the hypothesis that the number of differentiated basaltic objects in the Main Belt should be much higher than previously assumed. We show results for the ~25 V-type asteroids outside the dynamical Vesta family in the Main Asteroid Belt.
Structural analysis of the dust tail of Comet NEOWISE (C/2020 F3)
Authors: Afghan Qasim , H. Jones Geraint , Price Oliver , J. Coates Andrew
Published: September 2022

Comet NEOWISE (C/2020 F3) displayed a highly structured dust tail, exhibiting the most prominent dust tail features visible from Earth since Comet McNaught (C/2006 P1) in the Southern Hemisphere and Comet Hale-Bopp (C/1995 O1) in the Northern Hemisphere. Using images taken by the amateur astronomer community, this dust tail is analysed using the Finson-Probstein model. The comet’s position in the sky in amateur images is calculated using an open source algorithm [1], the position and exact time then calculated, and the dust tail is simulated. This modelled dust tail structure is then projected and overlaid onto the comet image to directly compare and identify similarities and discrepancies between the model and the image. Using the novel analysis method of mapping the image to a plot of dust grain beta against ejection time[2], tail structures can be more easily identified, analysed and tracked over time (where beta is the ratio of force due to solar radiation pressure and that due to the sun’s gravity).

Dust tail structures such as syndynic bands and striae (near-parallel linear features) have been identified and characterised in terms of dust ejection time and dust beta values. These structures are tracked over time, and compared to the analysis of similar structures seen in C/2006 P1 (McNaught) [2]. There are some clear differences between the two comets, particularly in the alignment and arrangement of their striae, most likely due to different heliospheric conditions during each comet’s perihelion passage.   

These results, all based on amateur observations, provide a thorough description of Comet NEOWISE’s dust tail to contribute to the collection of cometary dust tail profiles currently available. This will enable convenient comparison between comets in the future, and will eventually enable population studies on cometary dust tails and their features. Due to the comet’s very high activity, it also exhibited a rarely seen tail of neutral sodium atoms. This sodium tail has also been parameterised in this work, with an estimated ionization lifetime of the sodium atoms of 17 hours ± 2 hours.

 

 

[1] Lang, Dustin, David W. Hogg, Keir Mierle, Michael Blanton, and Sam Roweis. 2010.”Astrometry.net: Blind Astrometric Calibration of Arbitrary Astronomical Images”. The Astronomical Journal 139 (5): 1782-1800. doi:10.1088/0004-6256/139/5/1782.

[2] Price, Oliver, Geraint H. Jones, Jeff Morrill, Mathew Owens, Karl Battams, Huw Morgan, Miloslav Drückmuller, and Sebastian Deiries. 2019. "Fine-Scale Structure In Cometary Dust Tails I: Analysis Of Striae In Comet C/2006 P1 (Mcnaught) Through Temporal Mapping". Icarus 319: 540-557. doi:10.1016/j.icarus.2018.09.013.