Europlanet Science Congress 2021
Virtual meeting
13 – 24 September 2021
Europlanet Science Congress 2021
Virtual meeting
13 September – 24 September 2021

Session programme


SB – Small Bodies (comets, KBOs, rings, asteroids, meteorites, dust)

Programme group coordinators: Gianrico Filacchione, Marco Delbo, Michael Küppers, Jean-Baptiste Vincent


The asteroids in particular and the asteroid-comet-dwarf planet continuum in general bear the signature of the birth of the solar system. Their observed properties allow for testing theories regarding the evolution of the solar system's planetary objects and of their prospective development. Additional important insights into this exciting field of research are provided by the laboratory investigations of the samples delivered to the Earth in the form of meteorites and by sophisticated numerical models.
The session will gather researchers of different communities for a better understanding of the evolution and properties of small bodies, in particular the parent bodies of meteorites. It will address recent progresses made on physical and chemical properties of these objects, their interrelations and their evolutionary paths by observational, experimental, and theoretical approaches.

We welcome contributions on the studies of the processes on and the evolution of specific parent bodies of meteorites, investigations across the continuum of small bodies, including comets, ranging from local and short-term to global and long-term (thermal and thermochemical) processes, studies of the surface dynamics on small bodies, studies of exogenous and endogenous driving forces of the processes involved, as well as statistical and numerical impact models for small bodies observed closely within recent space missions (e.g., Hayabusa2, New Horizons, OSIRIS-REx).

Convener: Wladimir Neumann | Co-conveners: Marco Delbo, Sabrina Schwinger

Impact processes shaped the Solar System, and modify planetary surfaces and small bodies until today. Impacts also have a technical application for Planetary Defence, exemplified by the joint ESA/NASA Asteroid Impact and Deflection Assessment (AIDA) collaboration. This session aims at understanding impact processes at all scales in terms of shock metamorphism, dynamical aspects, geochemical consequences, environmental effects and biotic response, and cratering chronology. Naturally, advancing our understanding of impact phenomena requires a multidisciplinary approach, which includes (but it is not limited to) observations of craters, strewn field or airbursts, numerical modelling, laboratory experiments, geologic and structural mapping, remote sensing, as well as petrographic and geochemical analysis of impact products.

We welcome presentations across this broad range of studies about natural or artificial impact collision phenomena on planetary and small bodies. In particular, we encourage work that bridges the gap between the investigative methods employed in studying planetary impact processes at all scales.

Co-organized by OPS/SB
Convener: Elena Martellato | Co-conveners: Chrysa Avdellidou, Christopher Hamann, Isabel Herreros, Robert Luther, Jens Ormö

This session aims to highlight new challenges and the missing building blocks needed to understand the composition and physical properties of the material of primitive bodies, using laboratory work on meteorites or other available extraterrestrial materials as well as terrestrial reference materials (rocks, minerals, ice, organics). Results of these laboratory studies with relevant references to modelling early processes in the solar system, including the formation/evolution of small bodies, and in support of ongoing and planned missions to study these objects are welcome.
The session focuses on the origin of inorganic and organic matter in different astrophysical environments and welcomes contributions on laboratory investigations and models of parent bodies of various meteorite groups, IDPs, asteroids, comets and dwarf planets.
This includes experimental work on the composition and physical properties of dust regoliths, the observation and characterization of laboratory analogues and resulting implications for models of small body formation and evolution. In addition, there is a special focus on organic matter (detection and evolution of organic components in the interstellar medium, observation and distribution of organic matter in the protosolar disk, characterization and evolution of organic matter in the primitive bodies and on planetary surfaces).

Public information:

Dear SB3 contributers,

Thank you again for your contributions during the live session on Thursday, September 16.

In the middle of the conference, I would like to ask you to please answer any questions you may have via Slack in order to promote the exchange of results.

So check back from time to time.


Convener: Gabriele Arnold | Co-conveners: Jörn Helbert, Eric Quirico

Electromagnetic scattering phenomena play a key role in determining the properties of Solar System surfaces based on observations using different techniques and in a variety of wavelengths ranging from the ultraviolet to the radio. This session will promote a general advancement in the exploitation of observational and experimental techniques to characterize radiative transfer in complex particulate media. Abstracts are solicited on progresses in numerical methods to extract relevant information from imagery, photometry and spectroscopy in solid phase, reference laboratory databases, photometric modeling, interpreting features on planetary surfaces, mixing/unmixing methods, software and web service applications.

Convener: Frédéric Schmidt | Co-conveners: Stéphane Erard, Maria Gritsevich, Antti Penttilä

Space and ground based observations of the small body populations in the Solar System are continuously reshaping our understanding of how these objects were formed and evolved. New data and theoretical advances, as well as the discovery of interstellar objects and extrasolar comets give us new insights on the physical and dynamical properties of small bodies. The goal of this session is to highlight recent results from outer planetary system objects (comets, KBOs, Centaurs, interstellar, …) that provide fundamental clues about the early stages of planetary systems. We aim to explore the continuum of small bodies and the overlap between different populations through a balanced set of contributions from ground based observers and space missions (e.g. Rosetta, New Horizons)

Convener: Jean-Baptiste Vincent | Co-conveners: Aurelie Guilbert-Lepoutre, Michael Küppers, Alessandra Migliorini

Currently there are over 1 million asteroids discovered. Each month over 1 mln astrometric and photometric observations are reported to the Minor Planet Center permitting dynamical and physical studies. Owing to large ground- and space-based surveys (such as Gaia, SDSS, ATLAS) hundreds of thousands of bodies can be at least partly physically characterised.

Those numerous, sparse and often incidental asteroid observations are balanced by relatively small in numbers but dense, targeted and accurate ground-based measurements. Those allow for a more detailed, tailored analysis, both in terms of observing techniques currently not available in survey mode (e.g. polarimetry, spectroscopy) and time spent on a single object.

The aim of this session is to open the discussion about the contribution of traditional vs./and survey-like data to our understanding of the origin and evolution of individual asteroids and populations. Furthermore what do they bring-in in terms of answering the big questions in planetary science such as formation and evolutions of the Solar System, planets and other planetary systems.

We invite all contributions concerning physical and/or dynamical modeling of small bodies based on traditional observations as well as survey-like data.

Convener: Dagmara Oszkiewicz | Co-conveners: Irina Belskaya, Agnieszka Kryszczyńska, Anna Marciniak

The space exploration of small Solar System bodies has provided major breakthroughs in our understanding of Solar System formation and evolution. Now that the Rosetta comet rendezvous and landing has passed and the Hayabusa 2 and OSIRIS-ReX sample return missions have finished their operations at the target asteroids, it is time to prepare future space mission for small bodies exploration. This session calls for presentations of the upcoming missions by ESA (Hera, Comet Interceptor), NASA (DART, Lucy, Psyche), JAXA (DESTINY+, MMX), and CNSA (name to be determined).
Contribution about mission and instrument concepts for the more distant future are invited as well.

Co-organized by MITM
Convener: Michael Küppers | Co-conveners: Tomoko Arai, Andy Cheng, Gianrico Filacchione, Harold Levison, Jean-Baptiste Vincent, Xiaojing Zhang

This merged session welcomes a broad range of presentations about future missions and instrumentation, and has a particular focus on small satellites. Recent advances in small platforms make it possible for small satellites, including CubeSats, to be considered as independent or complementary elements in planetary exploration missions, for example the small probes as part of the Hayabusa 2, DART and Hera mission. Presentations on Deep Space Planetary CubeSats, e.g. the small satellites accompanying the F-class ESA mission Comet Interceptor and those selected or proposed for the NASA SIMPLEX program are welcomed. Concepts for future mission may either be an augmentation to larger missions or as stand-alone missions of their own. We encourage presentations on new Planetary science mission architectures and associated technologies, as well as dedicated instrumentation that can be developed for these applications.

Co-organized by TP/OPS/SB
Conveners: Patricia Beauchamp, John Robert Brucato | Co-conveners: Marilena Amoroso, Vincenzo Della Corte, Iaroslav Iakubivskyi, Simone Pirrotta, Michel Blanc, Manuel Scherf, Thomas Smith

The goal of this session is to cover numerical simulations and relevant laboratory investigations related to the Small Bodies (comets, KBOs, rings, asteroids, meteorites, dust), their formation and evolution, and the instruments of their exploration. This session is specially focused on the interdisciplinary approach in the development of models (formal descriptions of physical phenomena), experiments (on ground and in micro-gravity), and mathematical simulations (computational methods and algorithms of solution) of various astrophysical phenomena: (i) dusty gas cometary atmospheres; (ii) volcanic activity on icy satellites (e.g. Enceladus and Io); (iii) planetary body formation (e.g. via pebbles growth), and planetesimal dynamics.

This session will include an introduction and discussion of new and/or existing laboratory studies in simulated space-like environments and models, experimental techniques, computational methods that can address the results of analytical, experimental and numerical analysis (with respect to computational methods and algorithms of solution) on the above described studies.

Abstracts on thermophysical evolution models of small bodies interiors as well as on the modeling of atmosphere and exosphere are welcome.

Co-organized by OPS
Convener: Vladimir Zakharov | Co-conveners: Vincenzo Della Corte, Marco Fulle, Stavro Lambrov Ivanovski, Raphael Marschall, Alessandra Rotundi, Diego Turrini

Thanks to the advancement of observational techniques from Earth and space, our knowledge of planetary ring systems and protoplanetary disks has greatly improved. While these two classes of objects differ by orders of magnitude in dimension and evolutionary stage, they offer a unique opportunity to investigate common dynamical processes that can shed light on the formation, composition and evolution of planetary systems. Although rings are common companions of the outer planets in our solar system, so far we do not yet have firm evidence of similar structures around exoplanets. In this respect, the characteristics of solar system rings can be used as a benchmark to tune ongoing exo-ring surveys. Conversely, high-angular resolution images obtained with new instruments such as the ALMA interferometer and SPHERE on VLT have revealed that protoplanetary discs are also characterized by substructures such
as gaps and narrow rings. The formation of these rings can be explained by the dynamical interaction of the gas and dust in the disc with one or more embedded planets. Similar processes are also common in planetary rings, as revealed by the unprecedented spatial
resolution of Cassini observations at Saturn. In this session we invite abstracts related to both theoretical and observational studies of
planetary rings and protoplanetary disks, as well as exo-ring research.

Co-organized by OPS/EXO
Convener: Philip D. Nicholson | Co-conveners: Gianrico Filacchione, Linda Podio, Claudia Toci

More than 10^7 kg of extraterrestrial objects or meteoroids ranging in size from a few microns to tens of meters in diameter enter the Earth’s atmosphere every year. A small fraction of these yields free samples of extraterrestrial matter - meteorites - for laboratory study. The majority, which burn up or ablate completely in the Earth’s atmosphere, appear as visible meteors in the night sky. Recording meteor activity and modelling the process of ablation allow us to measure directly the flux of small planetary impactors. This provides the 'ground truth' for estimating present cratering rates and planetary surface ages by implication.

The application of the latest observational and modeling techniques has rendered meteor science as one of the leading avenues for investigating the nature and origin of interplanetary matter and its parent bodies. This session will provide a forum for presenting fundamental results and novel ideas in this area and informing the broader planetary science community of the interdisciplinary impact of present and future work.

Convener: Maria Gritsevich | Co-convener: Eleanor Sansom

Shape, gravity field, orbit, tidal deformation, and rotation state are fundamental geodetic parameters of any planetary object. Measurements of these parameters are prerequisites for e.g. spacecraft navigation and mapping from orbit, but also for modelling of the interior and evolution. This session welcomes contributions from all aspects of planetary geodesy, including the relevant theories, observations and models in application to planets, satellites, ring systems, asteroids, and comets.

Co-organized by OPS/SB
Convener: Alexander Stark | Co-conveners: Hannah Susorney, Anton Ermakov, Marie Yseboodt

Metals, in particular iron and nickel, have been found in cometary dust by in-situ experiments on board the Giotto and Rosetta spacecrafts as well as in dust particles collected by the Stardust space probe. They essentially appear in silicate, sulfide and metal grains. Two Sun-grazing comets, the Great Comet of 1882 and C/1965 S1 (Ikeya-Seki), approached the Sun so close that dust grains vaporized, revealing lines of several metals, in particular FeI and NiI emission lines in the coma spectrum. However, it came as a surprise to find numerous FeI and NiI emission lines in high-resolution spectra of comets observed at large heliocentric distances, where the equilibrium temperature is far too low to allow sublimation of silicates and sulfides. Moreover the average NiI/FeI abundance ratio derived using a fluorescence model appears one order of magnitude higher than the Solar value. In this talk, I summarize this discovery and present some hypotheses to explain these unexpected results that indicate that constituents of the cometary nucleus or processes in the coma are still missing.

Co-organized by SB
Convener: Michael Küppers
Thu, 16 Sep, 14:20–14:50 (CEST)

It is often heard that planetary rings (PR) are local dynamical laboratories, important for understanding protoplanetary disks (PPD). While they are very different in profound ways, PR and PPD indeed do inform, illustrate, or complement each other, theoretically and observationally.

1) Con o senza gas? The most profound difference between PR and most PPD is that gas plays a critical role in most PPD and a very minor one in most PR. There are however important PPDs that lack gas (debris disks) in which there are PR connections in the areas of collisional cascades and small particle size distributions.

2) Fluid dynamics is fundamental to PR as it is to PPD; in PR the "fluid" pressure and viscosity are generated by very gentle collisions between cm-m size particles, acting like molecules in a dense gas. In PPD, the gas provides pressure and viscosity, but the viscosity is strongly dependent on the intensity of PPD gas turbulence - which is poorly understood and hard to observe.

3) Radial transport of mass and angular momentum is similar in PR and PPD: in PRs, collision-scale viscosity is analogous to molecular kinematic viscosity and there is not really any equivalent to turbulence. However, angular momentum in both PR and PPD can also be powerfully transported over longer ranges by gravitational effects, including spiral waves that obey the same physics.

4) In spite of various attempts to ignore it, the messy physics of collisional particle sticking and bouncing is important in both environments. The outcome of growth by sticking in PPD - that determines the path to planetesimal formation - depends critically on the intensity of turbulence, whereas in PR growth is limited by tidal forces.

5) Large scale radial structure (strong surface density fluctuations and empty gaps) is generated by gravitational torques associated with local or nonlocal large objects. In both PR and PPD, local gravitational instabilities may be important. There is abundant smaller-scale structure revealed by Cassini in Saturn's rings that we do not understand, that may lead to further insights.

6) PRs and PPDs are not closed systems - infall of matter from beyond the system, and loss of matter to the central object, are very important to the compositional and radial evolution of both systems. Indeed, infall may be our best constraint on the age of Saturn's rings, and also limit their lifetime.

7) Short timescales are surprisingly important. We see features in PR evolving before our eyes. Saturn's rings may be both geologically young AND short-lived. In PPD, the most youthful stages - still the least well observed or understood - may be the key to many of the puzzles of the meteorite record, planetesimal formation, and the path to planets.

Co-organized by SB
Convener: Gianrico Filacchione
Thu, 23 Sep, 17:30–18:00 (CEST)