Abstracts Oral Presentations Display - SSW

PLASMA COMPOSITION EVOLUTION IN A SOLAR FLARE - THE EFFECT OF RECONNECTION OUTFLOW - ANDY SHU HO TO

We analyse the coronal elemental abundances of the X8.2 flare on 2017 September 10 using spatially resolved measurements from Hinode/EIS (EUV Imaging Spectrometer). Using both the Ca XIV 193.87 Å/Ar XIV 194.40 Å and Fe XVI 262.98 Å/S XIII 256.69 Å composition diagnostic ratios, we show that the flare loops exhibit a large variation of coronal abundances, with the loop tops showing enhanced coronal abundances that decrease to photospheric values toward the footpoints. We propose that this variation is caused by two physical processes. The highly fractionated abundance at the loop top is likely associated with plasma downflow from the plasma sheet, which has coronal abundances. Meanwhile, upflows caused by chromospheric evaporation/ablation fill the loop footpoints with unfractionated photospheric composition. Mixing between these sources produces the observed gradient along the loops. Our findings provide a novel explanation for the composition discrepancy observed between Sun-as-a-star and spatially resolved flare composition measurements, and have significance for understanding loop top brightenings also known as bright knots. Spatially resolved spectroscopy proves critical for revealing these complex abundance structures.

INSIGHTS FROM MODELLING HOW AEOLIAN-FLUVIAL INTERACTIONS SHAPE THE SURFACE OF TITAN - ELENI BOHACEK

Fluvial and aeolian surface processes have been observed on Titan. Methane precipitation feeds fluvial landforms (FLs), 50% of which exhibit rectangular drainage patterns (a much rarer pattern on Earth typically due to conjugate faulting). We developed the Titan Aeolian Fluvial Interactions model to simulate interacting fluvial and aeolian processes on Titan. This landscape evolution model is based on a coupled implementation of the Caesar-Lisflood fluvial model, and Discrete ECogeomorphic AeolianLandscape model (DECAL) dunes model. The Caesar-Lisflood fluvial model routes water over a digital elevation model and calculates erosion and deposition from fluvial and slope processes and changes elevations accordingly. The DECAL model is based on the Werner slab model of dunes, which simulates dune field development through self-organization. We show that although Titan dunes are potentially inactive, they are so much larger relative to rivers that dunes represent major topographic obstacles to rivers. Much like on Earth, we found that the nature of duneriver interactions are dependent on the relative orientations of dune crestlines and the river channel. In some cases, where the river ran semi-parallel to dune crests, the river could be funnelled upslope along interdune corridors, forming rectangular drainage patterns. In other cases when the relative orientations were not parallel, the river would pool and then breach the lower area of a dune crest and flood deeper into the dune field, delivering sediment in the process. These findings help our understanding of FL drainage patterns, distribution, and planforms, and suggest a mechanism for fluvial sediment delivery into dune fields.

CHARACTERIZING EXOPLANETS WITH JWST/NIRSPEC - STEPHAN BIRKMANN

The study and characterization of exoplanets and their atmospheres is one of the most rapidly evolving fields in astronomy and astrophysics in the last decade. Transit, eclipse, and phase curve observations of these celestial bodies provide an avenue for understanding planetary diversity, investigating planetary system evolution, and ultimately advancing the search for extraterrestrial life.
In this talk, I will present first results and findings of a JWST/NIRSpec program targeting four exoplanets ranging from hot Jupiters (WASP-52 b) and giant planets (WASP-107 b) down to more temperate super-Earths (L98-59 d) by means of transit and eclipse observations, as well as a full phase curve measurement of a single target (WASP-43 b).

SOLAR ORBITER AND ALMA OBSERVATIONS OF SMALL-SCALE BRIGHTENING FEATURES IN THE SOLAR ATMOSPHERE - HENRIK EKLUND

Observations at millimeter wavelengths provide accurate measurements of the plasma temperature of the heavily dynamic chromosphere, and the Atacama Large Millimeter/sub-millimeter Array (ALMA) offers ground-breaking observations in terms of sensitivity and angular resolution. In particular, synergy-observations with the Solar Orbiter are very powerful in order to probe the solar atmosphere.
We study so-far very perplexing small scale brightening features at both extreme ultraviolet wavelengths in Solar Orbiter data and at mm-wavelengths in ALMA data, to characterise and determine their formation process. Understanding their formation process increase our understanding of their possible contribution to the heating of the solar corona, the production of solar wind, violent eruptions and flares.

MACHINE LEARNING TECHNIQUES APPLICATION TO ASTROMETRY IN THE GAIA MISSION - NELLY GAILLARD

The data processing task of the Gaia mission is large and complex. One of its central elements is the Astrometric Global Iterative Solution (AGIS), which produces and delivers the core astrometry data products.
One of the most challenging tasks that we need to tackle in the software producing Gaia’s astrometric solution is creating a calibration model accurate enough to consider the subtle effects, since they may have an impact on the quality of the solution at the micro-arcsecond level.
Among AGIS related data, the first to be analysed are the post-fit residuals. These are the differences between the observations and the predictions obtained using the AGIS source, attitude and calibration model. Up to now, they have been manually explored, by plotting them in different partitions to identify anomalous clusters of points. This task is time consuming and lends itself to automated analysis by means of machine learning techniques, which could make the procedure more efficient and systematic.
With the objective of performing anomaly detection on the residuals, the first task is to define what an anomaly is, which has been done exploring different data visualization and feature engineering techniques. In this poster we will present an overview of the project and its status, highlighting possible ways forward.

WITNESSING GALAXIES FATE SINCE THE END OF COSMIC DAWN: A STAR-FORMATION QUENCHING STORY - THIBAUD MOUTARD

Well documented over ≥12 billion years (e.g. Davidson et al 2017), the continuous increase of the fraction of quiescent galaxies (where star formation has stopped) is the statistic expression of the quenching —i.e. the permanent shutdown— of star formation in galaxies. Such permanent quenching of the star formation requires, however, mechanisms able to suppress and prevent the cold-gas infall, which one may expect to vary depending on galaxies properties and environment.
The diversity of quiescent galaxies (e.g. in terms of stellar mass and morphology) pleads indeed for the coexistence of different quenching channels since cosmic noon (Faber et al. 2007, Peng et al. 2010, Schawinski et al. 2014, Moutard et al. 2016b). At higher redshift, the physical processes which were at play in the early quenching of the very first quiescent galaxies a few 100Myrs after their formation (e.g. Chworowsky et al. 2023) are expected to be different again.
I will present unprecedented analysis of the connection between the star formation quenching and the morphological transformation of galaxies since z ~ 7, drawing on the deepest, sharpest near- and mid-infrared observations ever conducted (even) with JWST (respectively, ~29 and 31mag at 3.6 and 5.6µm), as part of JADES (NIRCam & NIRSpec GTOs) and MIDIS (MIRI GTO), combined with ultra-deep HST imaging over the HUDF. I will characterise the co-evolution between galaxies sSFR and morphology through the green valley, depending on their stellar mass, and discuss the different quenching scenarii that our results support across cosmic time over the last ~13 billion years.

MEAD: MEASURING EXTINCTION AND ABUNDANCES OF DUST - MARJORIE DECLEIR

Interstellar dust has a significant impact on many astronomical research fields, as it absorbs and scatters a large fraction of the star light, and influences star formation and galaxy evolution at all cosmic times. Understanding the properties of the dust grains is thus crucial to derive precise knowledge of any object in the Universe that is obscured by dust, as well as to constrain the initial conditions for star and planet formation.
We can gain insight into the properties of the interstellar dust by studying its extinction effect on the star light. Multi-wavelength continuum extinction contains information about the average dust grain size along the line of sight, while extinction features reveal the composition of the dust grains. In addition, abundances of the elements that make up the dust grains enable us to quantitatively measure the chemical composition of the grains. With the MEAD (Measuring Extinction and Abundances of Dust) project we are combining these two methods to constrain the dust properties in our Galaxy. We obtained ultraviolet spectra with the Hubble Space Telescope to measure dust abundances in a sample of Milky Way sightlines, that span a range of environments. Furthermore, we will combine these abundance measurements with literature UV extinction curves, as well as new near- and mid-infrared extinction curves that we are measuring with our James Webb Space Telescope observations, for the same sightlines.
In this talk, I will explain the goals of MEAD and walk you through the first results. I will also show how the synergy between multi-wavelength data from the HST and JWST, as well as other telescopes is advancing our understanding of interstellar dust properties and how they vary in our Galaxy.

MACHINE LEARNING FOR SPACE SCIENCE: PROJECTS AND COMMUNITY BUILDING - SANDOR KRUK

In the past year, our Data Science team has dedicated efforts to foster a community centered on using machine learning in space science. We have actively involved young scientists at ESA in various activities on ESA Datalabs and are building knowledge and expertise through a range of projects, from natural language processing to computer vision. In this presentation, I will highlight some of our current projects, such as fine-tuning for the first time a large language model for astronomical research. I will discuss the role of infrastructures such as ESA Datalabs and discuss the scientific networks that have emerged throughout these ML initiatives, such as UniverseTBD.

INSPIRATION THROUGH SPACE SCIENCE: EXOPLANET THEMED EDUCATION ACTIVITIES FOR SECONDARY STUDENTS - KATE ISAAK

The topic of exoplanets is connected directly to the simple and profound question of whether we are alone in the Universe, capturing the imagination of scientists and the public alike. As such, it provides an excellent means through which to engage school students in some of the thrills of science and, critically, to teach science, technology, engineering and mathematics (STEM) core skills.
In this contribution we give an overview of a collection of exoplanet inspired classroom activities and resources that have been developed through a collaboration between ESA Education and scientists working in SCI and beyond. The emphasis of the activities has been on transit photometry and more specifically ESA’s CHEOPS mission, with the underlying theme of using in-flight CHEOPS observations to engage young people. We combine the overview of the activities with an introduction to the ESA Education portfolio.

EMPOWERING RESEARCHERS WITH COMPREHENSIVE DATA ACCESS FOR THE ESA’S JUICE MISSION - EMMA VELLARD

Now that JUICE is on its cruise, the first datasets of the nominal mission are expected in 2032. A need for an integrated and user-friendly data environment to support the research community and their analysis efforts was identified a few years ago. In response to this demand, we have been working on the development of an extensive data environment tailored for the JUICE mission. This environment is designed to streamline and enhance the research process by offering researchers a centralized platform containing a wealth of information. Our platform will encompass a diverse array of data, including details about the spacecraft itself, such as trajectory, instrumentation and 3D models. In addition, it will provide technical data and specifications necessary for researchers to effectively interpret the mission’s observations. It will also house valuable information on the scientific aspects of the JUICE mission, such as workshop presentations, latest published papers or relevant databases. By providing comprehensive, easily accessible information, we aim to empower researchers within the scientific community to conduct in-depth analysis and gain valuable insights into the JUICE mission’s data.

JADES: SCIENCE HIGHLIGHTS FROM THE GOODS DEEP-FIELDS - TIM RAWLE

We present an overview of recent results from the James Webb Space Telescope (JWST) Advanced Deep Extragalactic Survey (JADES), using 770 hours of guaranteed observations in the GOODS deep fields. The programme is intended as a comprehensive study of galaxy evolution from the highest redshifts to 'cosmic noon', combining 8-10-band tiered-depth NIRCam near-infrared imaging, extensive 0.6-5.3 micron NIRSpec multi-object spectroscopy targetting over 5000 faint sources, and coordinated parallel imaging in the mid-infrared using MIRI. Fourteen JADES papers have been published, with a further 25 submitted, accruing almost 800 citations. Scientific highlights include: detection of carbonaceous grains in large dust reservoirs within the first billion years of cosmic time, implying rapid production; remarkable extended Lyman-alpha emission at epochs previously expected to have highly neutral intergalactic medium; and discovery of a metal-poor galaxy at z=13.2, the current record-holder for a spectroscopically-confirmed redshift.

EARLY RESULTS FROM THE WISCI PROJECT: WEBB INVESTIGATION OF SILICATES, CARBONS AND ICES - SASCHA ZEEGERS

The diffuse interstellar medium plays an essential role in regulating the energy balance of galaxies, by processing starlight and driving molecule formation. It contains the input ingredients of dense star forming clouds and, consequently, of new stars and planets. Therefore, it is important to understand the properties, formation, and evolution of this dust. However, we lack a fundamental understanding of the dust cycle in galaxies and its main elemental building blocks: H, C, O, Si, Mg, and Fe. The imprints of dust on the spectra of stars reveal information about the composition and structure of the dust grains, which in turn can explain what happens to the grains as they travel through the interstellar medium (ISM).
In this talk I present the Webb Investigation of Silicates, Carbons and Ices (WISCI) project in which we study dust along the line of sight of twelve OB stars in the Milky Way, using JWST MIRI and NIRCam (GO cycle 1 program id 2183), HST STIS (cycle 30 program id 17078) and VLT XSHOOTER spectroscopy.
The wavelength coverage, sensitivity, and spectral resolution of JWST at near- and mid-infrared wavelengths in combination with HST and VLT observations enables us to study dust in the diffuse ISM in unprecedented detail. In this talk I will present the first exciting results from this study.

FINDING HIDDEN CONJUNCTIONS IN THE SOLAR WIND - ZOE FAES

This research aims to identify sets of in-situ measurements of the solar wind sampling the same volume of plasma at different times and locations in the heliosphere – referred to here as conjunctions. Observations of the same volume of plasma as it travels through the heliosphere allows for the characterization of the expansion of the solar wind. Specifically, this will enable us to test the current understanding of solar wind acceleration from the corona to the inner heliosphere using a greater sample of measurements than has been used in past research.
Using in-situ measurements from Solar Orbiter, Parker Solar Probe, STEREO-A, Wind and BepiColombo, we identify a set of criteria from known conjunctions and search for other instances in which the criteria are satisfied. To improve the performance of our statistical detection algorithm, we will use a machine learning model trained on synthetic observations to identify candidate conjunctions. The initial statistical analysis shows that correlation and time lag between timeseries are the best predictors of conjunctions. Initial results show a limited set of conjunctions which we hope to expand using machine learning methods.
The modular scientific software built over the course of this research will be released as an open-source Python package to ensure results can be easily reproduced and to facilitate further investigation of coordinated in-situ data.

DISSECTING THE MID-INFRARED HEART OF M83 WITH JWST - SVEA HERNANDEZ

Molecular gas is a critical ingredient in the recipe of star formation (SF) in galaxies. To fully understand the processes that govern SF, it is essential to accurately measure and characterize the distribution of H2 in star-forming environments. Since H2 is a weak rotational emitter, the molecular gas content in galaxies is typically inferred using indirect tracers such as the CO (1-0) transition. However, CO provides a partial census of the total H2 mass, particularly in regions with large quantities of CO-dark gas. A recent HST/FUV spectroscopic study suggested that S+ might be tracing large amounts of CO-dark gas in the core of M83. We have begun exploiting the unprecedented capabilities of JWST in the MIR, using the MIRI/MRS, performing a spatially-resolved study of the warm H2 gas in the heart of this face-on spiral galaxy. Our initial results indicate that ~75% of the total molecular gas mass in the core of M83 is contained in the warm H2 component, hidden to the CO tracer. The combination of the FUV capabilities of HST with the MIR sensitivity of JWST have allowed us to confirm, for the first time, S+ as a tracer of CO-dark gas in this particular metal-rich and highly active environment. To understand the fueling SF history through time, it is imperative that we test and develop tools to accurately estimate molecular gas mass directly probing the H2 reservoirs. JWST, with its unrivaled resolution and sensitivity is allowing us to do exactly that.

ASTROMETRIC BINARIES WITH DARK COMPANIONS IN THE GLOBULAR CLUSTER OMEGA CENTAURI - JOHANNES SAHLMANN

We present the discovery of the first astrometric binaries in the globular cluster omega Centauri. This was made possible by analysing 13 years of regularly-scheduled Hubble Space Telescope calibration observations in the cluster core. We determined the astrometric orbits of four binaries and their Keplerian parameters suggest periods of 9-19+ years and dark companions in the mass range of 0.7-1.4 solar masses, including at least one neutron-star candidate. We discuss the potential of astrometric binary searches in globular clusters in the context of the recent Gaia Focused Product Release and future Gaia data releases.

DEMOCRATISING DESIGN: A PRACTICAL GUIDE TO CREATIVE PROBLEM-SOLVING FOR ALL - EMMA DE COCKER

"Design appears ubiquitously—product design, web design, service design, fashion design—it is a term embraced by all. In your everyday work you may have to design a spacecraft, an interactive tool to allow your team to work together on the spacecraft or the public event where you will present your work on the spacecraft design. To give another example, I am currently working on the (re)design of the sci.esa.int pages.

So what is design? Attempting to pinpoint a definitive definition to such a versatile concept would be inconclusive. What remains open to discussion, however, is the design process. While dependent on team dynamics and available resources, the mindset designers adopt when approaching challenges, and the methodologies and tools they employ to develop solutions tend to align within a general pattern.

In this interactive talk, we will systematically dive into a typical design process illustrated by a simple but realistic use case. Together we will adopt the creative problem-solving mindset of designers. We will explore how gaining empathy involves not only understanding but actively involving all stakeholders in a co-creation journey. We will also demonstrate the delicate balance between applying established methodologies and following one’s own intuition and expertise. Finally, the exercise will depict the iterative and flexible nature of the design process, emphasising on the importance of systematic reflection at each stage."

HOW DOES STELLAR METALLICITY AFFECT THE ROTATION EVOLUTION OF LOW-MASS STARS? - VICTOR SEE

In recent years, there has been a growing body of evidence that the metallicity of a star affects how efficient its dynamo is. The central idea is that a star’s metallicity affects the depth of its convection zone and, therefore, the dynamo process. Metal-rich stars are expected to generate stronger magnetic fields and have stronger activity than metal-poor stars. From theoretical considerations, a star’s metallicity is also expected to affect its rotation evolution since angular momentum loss is ultimately a result of the dynamo. In this talk, I will present observational evidence that this is indeed the case.

MACHINE LEARNING SEARCH FOR GAIA DR3 ASTROMETRIC EXOPLANET ORBITS - PABLO GÓMEZ

The third Gaia data release (GDR3) contains ~170,000 astrometric orbit solutions of two-body systems located within ~500 pc of the Sun. The determination of the component masses of these systems usually hinges on incorporating complementary observations in addition to the astrometry, e.g., spectroscopy and radial velocities. Several GDR3 two-body systems with exoplanet, brown-dwarf, stellar, and black-hole components have been confirmed in this way. Using ESA Datalabs, we developed an alternative machine learning approach that uses only the GDR3 orbital solutions with the aim of identifying the best candidates for exoplanets and brown-dwarf companions. Based on confirmed substellar companions in the literature, we use semi-supervised anomaly detection methods in combination with extreme gradient boosting and random forest classifiers to determine likely low-mass outliers in the population of non-single sources. We employ and study feature importance to investigate the method's plausibility and produced a list of likely candidates for further study. Our preliminary findings suggest that this new approach is a powerful complement to the traditional and “manual” identification of substellar-companion candidates in Gaia astrometric orbits. It is particularly relevant in the context of GDR4 and its expected exoplanet discovery yield.

M DWARF STELLAR PARAMETER DETERMINATION WITH AUTOENCODERS AND DEEP TRANSFER LEARNING - PEDRO MAS BUITRAGO

The estimation of stellar parameters for M dwarfs often involves the comparison of observed spectra with different synthetic collections. In this process, a major source of uncertainty is the “synthetic gap” (difference between theoretical and observed spectra), which must be addressed beforehand to know the reliability of the parameter estimation.
In this work, we propose a deep learning (DL) methodology to bridge the synthetic gap in stellar parameter estimation, using a sample of high S/N, high resolution, spectra from 286 CARMENES survey M dwarfs. For this purpose, we built a two-step process that involves different deep learning approaches. In particular, we used deep transfer learning (DTL), which focuses on transferring knowledge from one model to another.
First, we trained a sparse autoencoder to effectively compress synthetic spectra from the PHOENIX-ACES models into a low-dimensional latent space. Using this trained autoencoder as a base model, we adopted a DTL approach to adapt it to the target domain (CARMENES spectra) while keeping the features learned in the data-rich source domain (PHOENIX-ACES spectra) frozen.
Using the low-dimensional encoded latent space from the PHOENIX-ACES spectra as input features, we trained a convolutional neural network (CNN) to build a regression model and estimate the stellar parameters of the 286 M Dwarfs.

Invited talk: The Flaring Sun: 2 Years of Solar Flare Observations with Solar Orbiter/STIX - Laura Hayes

Solar flares are intense bursts of radiation caused by the release of magnetic energy in the solar atmosphere, and they play a pivotal role in influencing space weather. As we are approaching the solar maximum, observations from Solar Orbiter's Spectrometer/Telescope for Imaging X-rays (STIX) are providing new insights into X-ray emissions from solar flare events. STIX has observed over 40,000 flares to date, since January 2021. In addition to new X-ray observations of solar flares that Solar Orbiter/STIX provides, the distinctive trajectory of Solar Orbiter, diverging from the Sun-Earth line, affords us the ability to detect flares from viewing angles markedly different from those accessible from Earth, affording us new possibilities to do stereoscopic science. In this presentation, I’ll present an introduction to X-ray flares, some new exciting results from STIX, and the importance of event lists and catalogs when doing coordinated science.

AT2023fhn (the Finch) and other animals - Ashley Chrimes

The extragalactic sky is full of transient phenomena, across the electromagnetic spectrum and beyond. These transients include cataclysmic events such as core-collapse supernovae, tidal disruption events, engine-powered transients (long gamma-ray bursts, super-luminous supernovae) and the detonations or mergers of stellar remnants (supernovae type Ia, short gamma-ray bursts).  The advent of wide-field, deep, and high-cadence optical sky surveys has led to the discovery of rapidly evolving transients, which rise and fade on timescales of days. One example are luminous fast blue optical transients (LFBOTs), the prototypical example being AT2018cow ('the Cow'). These events are among the optically brightest transients ever observed, are accompanied by luminous X-ray and radio emission, and evolve too rapidly to be explained by standard supernova models. Since AT2018cow, only a handful more LFBOTs have been discovered, and their origins remain unknown. I present multi-wavelength observations of LFBOT AT2023fhn, 'the Finch'. In stark contrast with other LFBOTs so far, Hubble data reveals that AT2023fhn lies far away from the nearest sites of prominent star formation - challenging a massive star progenitor interpretation. I give an overview of the leading models put forward to explain LFBOTs, and evaluate them in the context of AT2023fhn.

Acceleration and transport of solar energetic particles in the inner heliosphere - Laura Rodríguez García

"A new era of spacecraft probing the inner heliosphere make now possible the study of the spatial distribution of solar energetic particle (SEP) events closer to the Sun. Recent missions, such as Solar Orbiter, along with the constellations of spacecraft near 1 au facilitate the study of the radial dependence of SEP parameters, such as the peak intensity and spectrum. In this work, we use the solar energetic electrons (SEE) measured by the MESSENGER mission from 2011 to 2015 to derive statistical results about the radial dependence of some SEE parameters, which are compared with the results from Solar Orbiter near its first nominal perihelion in March 2022.  The main conclusions are: (1) There is a wide variability in the radial dependence of the electron peak intensities, but on average and within uncertainties, the radial dependence can be expressed as R-3, being R the heliocentric distance to the Sun. (2) Between near 0.3 au and 1 au, the energy spectrum of the near-relativistic electrons becomes softer. 
We also analyse the relations between the solar activity and the SEE peak intensities measured by MESSENGER, STEREO and ACE spacecraft during 2010-2015. A summary of the results, implications for the Space Weather research, and comparison with previous works is presented."
 

Could the dinosaurs have observed Saturn's rings?  - Nicolas Altobelli

Two main schools of thoughts are battling around the question of whether Saturn's rings are as old as the Solar System, if they formed together with Saturn, or were acquired more recently (young ring hypothesis). The Cassini mission acquired various measurements that need to be interpreted in a coherent way to find the correct answer. Radar and optical measurements constrain the amount of non-icy contamination by exogenous material accumulated over time by the rings, the current micrometeoroid infall has been characterised, as well as the total mass of the ring. Ring evolution models have been fed with those new measurements but still no consensus seems to emerge... we will present the latest status of the (sometime) heated discussions around the Age of the Rings.

The search for circumbinary planets - Matthew Standing

"Circumbinary planets, those which orbit both stars of a binary system, challenge our understanding of planet formation and orbital evolution. Planet formation around binary stars was thought to be difficult, and therefore these circumbinary planets were confined to the realm of science-fiction. Yet during its lifetime, Kepler discovered several of these objects. Since the discovery of Kepler-16b in 2011, 14 circumbinary planets have been discovered in 12 systems by transit missions. Future transit missions such as PLATO, will likely double the number transiting circumbinary planet candidates, and radial velocities would be required to confirm them. Despite the radial velocity method being the most established technique for planet detection, only recently has it become possible to detect circumbinary planets using radial velocity measurements. 
I will present a recent radial velocity discovery of a second circumbinary planet in the TOI-1338/BEBOP-1 system, where TESS had identified a 95-day circumbinary planet. This makes TOI-1338/BEBOP-1 the second multiplanetary circumbinary system ever discovered. I will also present an efficient method to calculate detection limits for radial velocity datasets with minimal assumptions, preliminary occurrence rates from the BEBOP and DMPP surveys, and describe plans for detection of circumbinary planets with PLATO.
Understanding how these planets form and how common they are can provide us with a unique insight into planet formation in these extreme systems."

JUPITER MASS BINARY OBJECTS - JUMBOS - SAM PEARSON

In recent observations of the Trapezium Cluster with the JWST, we have discovered and characterised a sample of 540 planetary-mass candidates with masses down to 0.6 Jupiter masses. In an unexpected twist we find that 9% of these planetary-mass objects are in wide binaries. The binary fraction of stars and brown dwarfs is well known to decrease monotonically with decreasing mass such that the binary fraction for the planetary-mass regime is expected to approach zero. The existence of substantial population of Jupiter Mass Binary Objects (JuMBOs) raises serious questions of our understanding of both star and planet formation. In this talk I will present the discovery of these JuMBOs, the 540 PMO candidates, and discuss the implications for our understanding of star and planet formation.

NEVER THROW AWAY OLD DATA! CYGNUS X-1'S FAST X-RAY VARIABILITY BEHAVIOUR IN THE 70S REVISITED - ERIK KUULKERS

Apollo 15 (and 16) did not only bring people to the Moon, but also experiments to study our neighbour and its environment. Onboard the Command and Service Modules (CSM's) were X-ray experiments, to explore the Lunar surface chemistry. These data, covering about 10% of the Lunar surface has been extensively used to study Lunar formation history and geological evolution. However, when traveling back to Earth, the experiments were also used for X-ray astronomy. These data had to be retrieved from a tape dump binary file. One of the extra-Solar sources observed is the famous black-hole X-ray binary Cygnus X-1.
X-ray states in X-ray binaries are mainly defined by their spectra and timing behaviour; these states correspond to different accretion regimes of the compact object. With the advent of high-throughput, high-time resolution experiments (such as onboard ASTROSAT, EXOSAT, Ginga, NICER, RXTE) emphasis has been shifting to study X-ray variability at high time resolution (typically less than milliseconds). For most of the earlier X-ray experiments in the 1960's and 1970's information is only available down to about milliseconds. We show that for Cygnus X-1, X-ray data taken with second to subsecond time resolution can uniquely help in defining its X-ray states. This is done by using digitized light curves and power density spectra as presented in the literature, from Uhuru (the 1st X-ray satellite), SAS-3 and HEAO-1, and various rocket experiments, in the 1970's, as well as newly analysed data from the X-ray experiment onboard Apollo 15 and the Netherlands Astronomical Satellite (ANS; the Netherlands 1st satellite).

THE BETA PIC DISK THROUGH THE EYES OF JWST - ISABEL REBOLLIDO VÁZQUEZ

Since the first imaging observation of the Beta Pic disk in 1984, the astronomical community has thoroughly investigated this system, finding large amounts of dust and gas, exocomets, and two planets. All of this makes it the perfect laboratory to investigate the dynamics and chemistry of the late stages of planet formation. The JWST GTO 1411 program was designed to investigate the dust component at near- and mid-infrared wavelengths, providing new insights on the dust morphology, composition, and distribution. The combination of the high sensitivity of the on board instruments with the 4QPM and Lyot coronagraphs allows for the most detailed images of the Beta Pictoris disk so far at this wavelength range, revealing new features and details in the dust distribution. In this talk, I will present JWST NIRCam and MIRI coronagraphic images, ranging from 1.82 to 23 microns. I will also summarize the analysis of prominent disk features observed for the first time, and compare it to previous ground and space based observations at multiple wavelengths.

GRAVITY-DRIVEN DIFFERENCES IN FLUVIAL SEDIMENT TRANSPORT ON MARS AND EARTH - LISSANE BRAAT

There is abundant evidence from fluvial landforms and deposits that early Mars had rivers that actively transported sediment and shaped its surface. Preserved ancient landscapes altered by water provide valuable insights into past processes on the planet’s surface and the presence of water. To better understand these landforms, we rely on knowledge gained from systems on Earth. However, is it fair to do so when the gravity on Mars is much lower? How does gravity affect sediment transport and the landforms created by water? In this study, we isolate the effect of gravity on sediment transport by water with an analytical river model. We used 32 sediment transport formulas to compare sediment transport rates on Earth and Mars for the same conditions except gravity. The results show that larger grains are picked up by the flow on Mars and the transport rate of sediment travelling in suspension is higher, and therefore total transport as well. Because grains transported near and on the bed are less affected than the grains in suspension, the effect of gravity varies with the way of transport and hence grain size. Therefore, gravity-driven differences in sediment transport by water should produce differences in sediment sorting, morphology and stratigraphy between Earth and Mars.

INVITED TALK: EUCLID EARLY RELEASE OBSERVATIONS PROGRAMME - RENÉ LAUREIJS

The ERO programme comprises one day of Euclid observations to showcase the Euclid capabilities at an early stage of the mission. The targets were obtained from proposals submitted by groups in the Euclid Science Collaboration. The ERO dataset offers several interesting fields, enabling a variety of scientific studies. We present a description of the programme, the organization, the scope of the data processing, and the upcoming milestones. We will also mention the first scientific results. The aim is to make the ERO data public as soon as the first batch of scientific analyses are completed in February 2024.

JAMES WEBB SPACE TELESCOPE UNVEILS FAINT BROWN DWARFS AND AN UNEXPECTED MOLECULAR DISCOVERY - CATARINA ALVES DE OLIVEIRA

I will present the discovery of new brown dwarfs in the star-forming cluster IC 348 using the James Webb Space Telescope. Two of the brown dwarfs show the spectral signature of an unidentified hydrocarbon. The same infrared signature was detected by NASA’s Cassini mission in the atmospheres of Saturn and its moon Titan. It has also been seen in the interstellar medium, the gas between stars. This finding, the first detection of this molecule in atmospheres outside of the solar system, challenges current atmospheric models of brown dwarfs and sheds new light on their formation and composition. Based on its luminosity and evolutionary models, the faintest new member of IC 348 has an estimated mass of 3–4 Jupiter masses, making it a strong contender for the least massive free-floating brown dwarf that has been directly imaged to date.
Press release: https://www.esa.int/Science_Exploration/Space_Science/Webb/Webb_identifies_tiniest_free-floating_brown_dwarf 
Published article: https://iopscience.iop.org/article/10.3847/1538-3881/ad00b7 

WHITE DWARFS WITH INFRARED EXCESS WITHIN 100 PC: GAIA AND THE VIRTUAL OBSERVATORY - RAQUEL MURILLO OJEDA

White dwarfs (WDs) are one of the most common objects in the universe. They are stellar remnants of low and intermediate mass stars, such as the Sun. WDs are compact objects, with typical masses around half a solar mass and planetary sizes. They are the key to understanding the composition and evolution of exoplanetary material around intermediate mass stars in their late stages of evolution.
In this talk we will describe the work aimed at identifying nearby (< 100 pc) WDs with infrared excess. Starting from the so far most complete volume-limited WD sample built from Gaia DR3 data (Jiménez-Esteban et al. 2023, 10.1093/mnras/stac3382), we used Gaia DR3 spectroscopic coefficients and GaiaXPy to obtain JPAS synthetic photometry. Using VOSA, a Virtual Observatory tool, we complemented JPAS photometry with infrared photometry gathered from astronomical archives. Then, we compared the SEDs to different atmosphere models to identify flux excess at infrared wavelengths.
Once we have got rid of the potential sources of contamination, the origin of the excess can be attributed to two causes: The presence of a low mass, cool companion or the existence of a circumstellar dust disk. Spectroscopic observations are required to discern between the two possible scenarios. This is why we started a follow-up program of the most promising candidates using the X-Shooter instrument at the Very Large Telescope. In this talk, we will show the first results obtained in this analysis.

MEDIUM RESOLUTION 0.97-5.3 MICRON SPECTRA OF VERY YOUNG BENCHMARK BROWN DWARFS WITH NIRSPEC ONBOARD THE JAMES WEBB SPACE TELESCOPE - ELENA MANJAVACAS

Spectra of young benchmark brown dwarfs with well-known ages is vital to characterize other brown dwarfs for which their ages are in general not known. These spectra are also crucial to test atmospheric models, in particular atmospheric retrieval models, which have the potential to provide detailed information about the atmospheres of these objects. However, to fully test atmospheric models, medium-resolution, long-wavelength coverage spectra with well-understood uncertainties are needed, such as the spectra provided by the NIRSpec instrument onboard the James Webb Space Telescope. In this paper, we present the medium-resolution JWST/NIRSpec spectra of two young brown dwarfs, TWA 28 (M9.0) and TWA 27A (M9.0), and one planetary-mass object, TWA 27B (L6.0), members of the TW Hydrae Association (~10 Myr). We show the richness of the atomic lines and molecular bands present in the spectra. All objects show signs of a circumstellar disk, via near-infrared excess and/or via emission lines. We matched a set of cloudless atmospheric spectra (ATMO), and cloudy atmospheric spectra (BT-Settl) to our NIRSpec spectra, and analyzed which wavelength ranges and spectral features both models reproduce best. Both models derive consistent parameters for the three sources and predict the existence of CH4 at 3.35 microns in TWA 27B. Nonetheless, in contrast to other slightly older objects with similar spectral types, like PSO 318.5-22 and VHS 1256b, this feature is not present in the spectrum of TWA 27B. The lack of the CH4 feature might suggest that the L/T transition of very young dwarfs starts at later spectral types than for older brown dwarfs.

WAS BEPICOLOMBO'S SECOND SWINGBY THE FIRST EVER PASSAGE THROUGH THE SOUTHERN PLASMA RING? - WILLI EXNER

Although the first three Mercury swingbys of BepiColombo had very similar trajectory configurations, plasma and magnetic field observations of the second swingby revealed a peculiar signature that had never been seen before.
Just a few minutes before the outbound passage of the dayside magnetopause, the plasma density and temperature increased and magnetic field decreased.
The previous and following swingbys did no show such features.
To understand how these localized observations play into the context of the global magnetosphere, we employ the 3D hybrid model AIKEF that models the global magnetosphere and its interaction with the upstream solar wind. We compare our model results for plasma density, temperature and magnetic field with the maltitude of BepiColombo's instruments and find significant agreement.
Our 3D results reveal that BepiColombo passed through Mercury's plasma ring  in the southern dayside region, just before crossing through the magnetopause. We find that no other spacecraft had ever traversed this particular region, and so BepiColombo's second flyby is going to be an important subject to investigate in order to understand the plasma ring inside Mercury's magnetosphere.

EXPLORING NEUTRON STARS' DEVOURING NATURE THROUGH STELLAR WIND STUDIES - CAMILLE DIEZ

The spectral and timing behaviour of High-Mass X-ray Binaries (HMXBs) offers a unique opportunity for the investigation of accretion onto compact objects and of wind structure in massive stars. The bright and persistent neutron star HMXB Vela X-1 is one of the key systems for such studies with both current and future instruments. It has a complex clumpy stellar wind, prominent cyclotron resonant scattering features (CRSFs) and strong flares. Understanding the variability of the system on both short time scales of a few hundreds seconds and along its 9d orbit with current instruments enables us to make predictions for future observations with XRISM and Athena and to devise the best observational strategy for Vela X-1.
Here, we analyse a new observation taken with XMM-Newton at orbital phase ~0.5 and follow the evolution of spectral parameters down to the pulse period (~300s) time-scale. The strong variability of absorption is associated with the presence of a large-scale wind structure combined with the variable line of sight as the neutron star moves along the orbit. In particular, we, for the first time, are able to trace the onset of the wakes with high time resolution and compare to predictions from simulations.

CAPTIVATING COMMUNICATIONS: CATCHING AND KEEPING YOUR AUDIENCE'S WANDERING EYE - NICOLE SHEARER

Your audience matters more than you do. You have only a few seconds to grab their attention, and they can look away at any time. If you want to be heard, you have to keep them at the centre of everything you write, say and create. What's the best way of getting them to read an article, watch a video, or pay attention during your presentation? How can we compete with funny cat videos, clickbait-y space drama and *ahem* bigger space agencies? This is a big, complex subject; two ESA Science editors will squeeze what they can into this 30 minute slot.

Determining the size distribution of asteroids is key for understanding the collisional history and evolution of the inner Solar System - PABLO GARCÍA MARTÍN

Aims. We aim at improving our knowledge on the size distribution of small asteroids in the Main Belt by determining the parallaxes of newly detected asteroids in the Hubble Space Telescope (HST) Archive and hence their absolute magnitudes and sizes.
Methods. Asteroids appear as curved trails in HST images due to the parallax induced by the fast orbital motion of the spacecraft. Taking into account its trajectory, the parallax effect can be computed to obtain the distance to the asteroids by fitting simulated trajectories to the observed trails. Using distance, we can obtain the object’s absolute magnitude and size estimation assuming an albedo value, along with some boundaries for its orbital parameters.

Results. In this work we analyse a set of 632 serendipitously imaged asteroids found in the ESA HST Archive. These objects were obtained from instruments ACS/WFC and WFC3/UVIS. An object-detection machine learning algorithm (trained with the results of a citizen science project) was used to perform this task during previous work. Our raw data consists of 1,031 asteroid trails from unknown objects, not matching any entries in the Minor Planet Center (MPC) database using their coordinates and imaging time. We also found 670 trails from known objects (objects featuring matching entries in the MPC). After an accuracy assessment and filtering process, our analysed HST asteroid set consists of 454 unknown objects and 178 known objects. We obtain a sample dominated by potential Main Belt objects featuring absolute magnitudes (H) mostly between 15 and 22 mag. The absolute magnitude cumulative distribution logN(H > H0) ∝ α log(H0) confirms the previously reported slope change for 15 < H < 18, from α ≈ 0.56 to α ≈ 0.26, maintained in our case down to absolute magnitudes around H ≈ 20, hence expanding the previous result by approximately two magnitudes.

Conclusions. HST archival observations can be used as an asteroid survey since the telescope pointings are statistically ran- domly oriented in the sky and they cover long periods of time. They allow to expand the current best samples of astronomical objects at no extra cost on telescope time.

Article: https://arxiv.org/abs/2401.02605

UNVEIL THE MICROPHYSICAL PROPERTIES OF EUROPA AND GANYMEDE SURFACES - GUILLAUME CRUZ MERMY

Europa and Ganymede are two moons of Jupiter with strong evidence for the presence of deep reservoirs of liquid water beneath their icy crust. They are also exposed to intense space weathering due to the continuous bombardment of electrons and ions from Jupiter's magnetosphere. Their surfaces therefore appear to be the key witness for understanding endogenous and exogenous processes, and for characterizing the state and evolution of these moons. Using reflectance spectroscopy, the study of the amount of light reflected as a function of wavelength, numerous studies have already revealed a wide variety of chemical compounds associated with water ice, such as sulfates, oxidants and chlorinates, confirming that these moons are prime candidates in the search for habitability in the solar system. However, surface composition alone cannot distinguish between endogenous and exogenous processes. To do so, it is necessary to finely characterize the microphysics of the ice (volume abundance, grain size, surface roughness, porosity). Using accurate radiative transfer modeling and Bayesian inference framework, we aim at retrieving such properties. By combining the data from the Galileo/NIMS instrument at moderate spectral resolution but high spatial resolution with the recent JWST/NIRSpec very high spectral resolution data we want to produce maps of the surface microphysical properties to differentiate between endogenous and exogenous processes.

MARS SMALLSAT MISSION & INSTRUMENTATION STUDIES FOR GLOBAL METEOROLOGY & SPACE WEATHER MONITORING - ALEJANDRO CARDESIN-MOINELO

We present here various scientific studies and efforts by the Martian atmospheric and magnetospheric science community, supporting the study and development of mission concepts with future small satellites and instrumentation that could be flown in orbit around Mars for meteorological and space weather monitoring, in line with the science and exploration priorities of ESA (SciSpaceE White Papers, Report & TerraNovae2030+) and NASA (MEPAG Future Program). Past and present Mars orbiters have provided great information on Mars surface and atmosphere, but focused mostly on targeted high-resolution measurements, lacking continuous global coverage.
Mars atmospheric phenomena (clouds and dust storms in particular) and space weather (solar wind, aurorae, radiation, …) require global, continuous, and simultaneous observations to fully understand the dynamic variability of Mars climate and environment. Several mission concepts involving satellite constellations have been studied in past years [Cardesin 2023, Montabone 2022&2021, Parfitt 2021]. These include satellite networks in different high-altitude orbit configurations, with great advantages for meteorology, space weather monitoring, and extra communication and navigation capabilities that could pave the way for future human exploration, providing services to other orbiters and surface assets. We summarize here the science case study for a minimal mission concept, based on [Montabone 2021], defining scientific priorities and requirements for a network of 3 low-mass, low-cost small satellites in areostationary orbit (equatorial, circular at ~17000km altitude). The small scientific payload would monitor atmospheric and surface parameters, aerosol (dust & ice) clouds, magnetic field and solar wind interactions. The nadir-viewing remote sensing payloads should at least include a visible camera (<5 km resolution), and a thermal infrared multi-band imager (<60 km resolution), potentially enhanced with a UV mapper or a near-IR high-resolution spectrometer. The basic space weather package would consist of a magnetometer, solar wind ion and/or electron detectors, and a space radiation monitor.

References
Cardesin 2023: Mars SmallSat missions: Spanish Science Consortium. Spanish Planetary Science Congress CPESS7
Montabone 2022: Continuous, Global, Simultaneous Mars Weather from Orbit, 7th MAMO
Montabone 2021: A Paradigm Shift in Mars Meteorology, EPSC 2021, 625.
Parfitt 2021: Small Mars Mission Architecture Study, Adv. Astron. 2021.
NASA: Mars Exploration Program Analysis Group, Future Program, April 2023
ESA: SciSpaceE White Papers & Report, 2023; Strategy Roadmap TerraNovae2030+, 2022

CONTRIBUTION OF MICROMETEOROID IMPACTS TO THE EXOSPHERES OF THE GALILEAN MOONS GANYMEDE AND EUROPA - ROZENN ROBIDEL

The exosphere is a thin atmosphere where the density is so low that atoms and molecules are unlikely to collide with each other. In the case of bodies with a substantial atmosphere (e.g. the Earth, Mars), the exosphere is the uppermost layer of the atmosphere, where it thins out and merges with outer space. In the case of airless bodies (e.g. the Moon, Mercury), the exosphere is the only atmosphere, in direct contact with the surface.
The exosphere of an airless body is transient and is continuously supplied by incoming sources (e.g. solar wind) and particles released from the surface through different processes (e.g. sputtering, micrometeoroid impact vaporization, photon- and electron-stimulated desorption…). The processes that release atoms and molecules in the exosphere are various according to the element (volatile or refractory) but also according to the body, its physical and chemical properties and its environment (e.g. surface, gravity, heliocentric distance, magnetic field, plasma environment…).
As micrometeoroids impact directly the surface of airless bodies, they release surface material into the exosphere by impact vaporization and ejection of dust grains. At Ganymede and Europa, micrometeoroid impact vaporization is often neglected as a source for neutral atmosphere models. However, micrometeoroid impacts result in eroding the surface and unveiling fresh material (the so-called impact-gardening). The contribution of micrometeoroid impacts is therefore important to understand the aging of surface and the relationship between endogenous and exogenous sources of surface material. Therefore, during my fellowship at ESA, I intend to study the contribution of micrometeoroid impacts on the formation of Ganymede and Europa exospheres, as a proxy to constrain their surface history. It is essential in the context of the upcoming missions ESA/JUICE and NASA/Europa Clipper, to explore the Jovian system in the early 2030s.