Three is not a crowd: Multiple companions as the cause or cure for binary star problems

Three is not a crowd:

Multiple companions as the cause or cure for binary star problems


3rd and 4th of August 2023

ESO Vitacura, Chile - Free registration

The principles of single and binary star evolution are generally accepted, but stars often form in triples or higher-order multiples, and the long-term evolution of these systems is poorly understood. The presence of a third star orbiting a binary system can significantly affect the evolution of the binary components, as well as drastically altering the evolution of the orbital parameters of the system. For example, dynamical interactions in three-body systems can lead to cycles of periodic variations of the eccentricity of the inner orbit and the mutual inclination between the two orbits. Additionally, the presence of the third star can enhance tidal effects in the binary and lead to interactions such as mass transfer and collisions.

The purpose of this meeting is to gather experts on multiple-star systems from all over Chile, with the goal of exchanging recent results and facilitating discussions about triples and higher-order multiplicity. We envision this meeting to be a fruitful and discussion-oriented in-person meeting where theorists and observers at different career stages exchange ideas. During this 2-day workshop, we hope to reach a global improvement of everyone's understanding of hierarchical multiple systems and trigger new collaborations and joint observing proposals.

Meeting structure

We want this meeting to be a platform for discussion in an organized but informal manner. For this reason, we will limit the number of on-site participants to 40 people, and we will ask everyone to motivate their participation in the registration form. 

We will have 3 different types of contributions and anyone can submit a proposal for one or more of them:

  • Contributed talks about a research topic (~15 minutes).

  • Discussion sessions (~10-minute talk about an open question followed by an open discussion chaired by the speaker).

  • Science case proposals (~10-minute talk about a science idea followed by a discussion in smaller groups to develop it further).


We particularly encourage everyone working in Chile and interested in triple or higher-order multiple systems to submit an abstract for one or more of these contributions. In particular, we would like to encourage participation from students and early-career scientists in the field.

Please note that organizers will provide coffee breaks, lunches, and a welcome cocktail on the first evening. We also plan to go for dinner together on Friday to a restaurant close to the venue, but everyone who wishes to attend this will have to cover their own expenses.

Important dates

22nd of May: Registration opens
15th of June: Abstract submission deadline
3rd of July: Participant list publication
17th of July: Program publication

Given the limited number of participants, we recommend not booking flights or accommodation until we confirm your contribution (by the 3rd of July).

For more information or questions, please contact