Letters of Intent received in 2021

LoI 2023-2136
Complex Planetary Systems II

Topics

- Planetary systems
- Complex systems
- Interdisciplinary approach
- Numerical and methodological latest techniques
- Application to exoplanets, disks, natural satellites, small bodies, rotational dynamics, history of planetary systems, cosmology, space debris

Rationale

The Celestial Mechanics group of the University of Namur (Belgium) was founded in 1970 by J. Henrard, and has followed a regular cycle of 8 years in the organization of international meetings : for the last ones, let us mention the IAU Colloquium 172, "Impact of modern dynamics in astronomy" in 1998, the meeting for the retirement of J. Henrard, in 2006 dedicated to the "Rotation of Celestial bodies" and the IAU symposium IAUS 310 "Complex Planetary Systems" in 2014. The next challenge was then initially scheduled for 2022 and postponed to 2023 because of the pandemic.

The symposium IAUS310 held in 2014 was a real success: more than 120 astronomers were present; the topic chosen for the meeting was directly linked to the research choice of the astronomers of Namur, who decided in 2010 to join the Complex Systems Center (naXys) of the University. The 2014 symposium was untitled "Complex Planetary Systems" to concretize this affiliation.
Complex systems are systems composed of interacting parts/agents whose local behavior, resulting from the interactions between them, cannot provide a complete understanding of the global behavior, i.e. when the system is considered as a whole, on a macroscopic scale.

This implies that several levels of description/modeling of the system should be present at the same time, micro-meso-macro. This forces complex systems to be studied by transdisciplinary teams, able to understand the whole construction and critically analyze the connections among the description levels. This vision is really efficient and challenging for space and astronomy sciences.

Now the center naXys has become a University Research Institute (www.naxys.be), with a specific research orientation to Space (dynamical astronomy, cosmology and astrobiology); the institute is presently chaired by an astronomer (A.-S. Libert) and the fusion of different scientific disciplines, around the Complex systems, has showed its powerful efficiency as, for example, in a recent event, the covid-19 pandemic modelled very precisely by a small multidisciplinary naXys team, gathering statisticians, network specialists, dynamicians and cosmologists.

The huge number of available observations (from ground and space) and their accurate precision, as well as the computational power and speed of our present-day computers have spectacularly changed the nature of the dynamical models, especially for planetary evolution studies. Planetology, celestial mechanics, cosmology, space geodesy have considerably evolved in that direction during the last decade, and have reinforced the need for crossing experiences and methods.

Let us mention several examples: the concept of habitability of an extrasolar planet, the dynamical history of the Solar System and other planetary systems, the rotation of planets and satellites linked to their internal structure, the motion of natural satellites needing astrometry, tides and dissipations, the thermal effects on the evolution of the rotating small asteroids, the long term evolution of space debris and satellites, including drags, shadowing effects, collisional chain reactions. In all these results the formal historical border between analytical and numerical approaches has now disappeared.

Our new symposium is a real opportunity to show the power of the interdisciplinary collaboration after more than ten years of experience. This is a unique occasion to gather astronomers of many disciplines together. The global thematic remains the planetary systems, but first, the tools and the methods have considerably evolved, second, the interdisciplinary position has touched more communities, and third, the presentation and the organization of the meeting will be innovative, with a priority to young bright speakers, on interdisciplinary topics, besides round tables, poster show, with some prizes encouraging the best presentations. CPS II will take advantage of CPS I first experience and realizations, but will open new doors and create collaborations, exchanges of ideas, combinations of techniques, sometimes unexpected, to solve the complex astronomical systems.

The Professor Anne-Sophie Libert, specialist of exoplanets dynamics, will chair the SOC, helped by an international panel of scientists, representing the main components of the topic, while the LOC and the proceedings edition will be under the responsibility of Professor Anne Lemaitre, with the help of several local researchers and administration staff.

The University of Namur is ideal to organize such an event, as proven in the past; the university will offer the lecture halls, the meeting rooms, the technological help, the access to the student dormitory, all available in this summer period. The city of Namur represents a very nice environment and proposes hotels and restaurants besides an historical citadel. The outreach program will be especially developed, under the responsibility of the Professor André Füzfa, laureate of the (outreach) Wernaers Prize.