Special Session SS19  3 July 2024

Stars, discs & planets: dynamics & evolution in multiple systems

News: If you wish to present your work, please consider sending a contributed talk through the EAS website. In case of questions, feel free to get in touch with the SOC.

Aims and scope

This session will be focused on the role and impact of stellar multiplicity on disc dynamics and planet formation & evolution --- taking into account relevant environmental effects such as gas infall, encounters, and photoevaporation. We will deliberately combine recent observations and theoretical results to fully exploit the strong synergy between different communities in the field of star & planet formation. The expected discussion between the participants will allow us to tackle two timely and relevant questions in the field: i) to which extent the current observations constrain physical processes in simulations; and ii) to which extent the theoretical predictions are (or will soon be) testable based on recent and ongoing surveys.

Summary of the session:
+ Part 1: Gas & dust evolution in young multiple stellar systems,
+ Part 2: Binary-disc interaction & evolution in multiples,
+ Part 3: Planetary dynamics and stability in multiples.

Part 1 (1.5h) will cover the formation process of multiple stellar systems in active Star Forming Regions and investigate the influence of stellar mass. Our overarching goal will be to better understand the connection between the formation of a multiple system and its parent cloud on larger scales. We plan to discuss recent surveys of young Class 0/I discs (e.g. FAUST and eDisks ALMA Large Programmes) where gas infall and nearby stars deeply affect disc formation and dynamics. The main goal of this block is to clarify which are the initial disc conditions in terms of temperature, mass, structure, dust, and composition around young multiple stars.

Part 2 (1.5h) will combine both the most recent disc observations (SPHERE, ALMA, Gravity) and the ongoing modelling of discs within multiple stellar systems (both with SPH and grid methods). We will focus on the gravitational (dynamical decay of unstable multiples, flyby) and radiation (winds, X-ray/UV fields) effects on disc evolution. The main objective of this block is to identify the dominant effects in shaping and dissipating protoplanetary discs within multiple stellar systems --- if possible as a function of the stellar mass. On top of this, we plan to discuss some open questions in the field regarding disc eccentricity, dust growth and planetesimal formation in discs.

Part 3 (1.5h) will highlight the emerging population of exoplanets in multiple stellar systems (e.g. TESS and Gaia surveys) and the stability predictions we can make based on celestial mechanics. In particular, we will discuss how gravitational perturbations, Kozai-Lidov oscillations, and Mean-Motion-Resonances unavoidably lead to peculiar orbital architectures --- which are characteristic of multiple stellar systems (as opposed to single systems). We aim at understanding how often this can actually be the explanation for misaligned and eccentric planetary architectures, and if there is any stellar mass dependance. In addition, we will focus on the testable predictions which would allow us to calibrate the efficiency of these processes thanks to the ongoing surveys ? both from the ground (e.g. ESPRESSO) and from space (e.g. TESS).


  • Part 1: Gas & dust evolution in young multiple stellar systems
  • + Multi-wavelength observations of young multiple stars
    + Modelling of disc formation around young multiple stars

  • Part 2: Binary-disc interaction & evolution in multiples
  • + Observations of Class II discs in multiple stellar systems
    + Disc evolution in binary and multiple stellar systems

  • Part 3: Planetary dynamics and stability in multiples
  • + Ongoing surveys of exoplanets in multiple stellar systems
    + Planet stability and evolution within multiple stellar systems

Invited speakers

  • Eleonora Bianchi (ORIGINS, Garching, Germany)
  • Rajika Kuruwita (HITS, Heidelberg, Germany)
  • Antonio Garufi (INAF, Arcetri, Italy)
  • Francesco Zagaria (IoA, Cambridge, UK)
  • Matthew R. Standing (ESA, Madrid, Spain)
  • Anne-Sophie Libert (U. of Namur, Belgium)

Scientific organisers

- Nicolás Cuello (chair, IPAG/UGA, Grenoble, France)
- Claudia Toci (co-chair, ESO, Garching, Germany)
- Jean-François Gonzalez (CRAL, Lyon, France)
- Andrew Winter (OCA, Nice, France)
- Bec Nealon (U. Warwick, England)
- Enrico Ragusa (U. Milano, Italy)
- Giuseppe Lodato (U. Milano, Italy)
- Benedetta Veronesi (CRAL, Lyon, France)
- Gaspard Duchêne (IPAG/UGA, Grenoble, France)


- Nicolás Cuello: nicolas.cuello @ univ-grenoble-alpes.fr
- Claudia Toci: claudia.toci @ eso.org

Updated on Tue Apr 09 09:42:44 CEST 2024