Understanding binaries

The life and death of multiple-star systems

The majority of stars are found in binary (or higher multiple) systems. Interactions between companion stars alter binary evolution. Many pieces of physics which determine how binariers form and evolve are currently uncertain; however, we have a variety of observations of different stages of binary evolution which can illuminate our understanding. The question is: how to translate observations to constraints on the physical processes that govern binaries? To solve this, we are developing Compact Object Mergers: Population Astrophysics and Statistics (COMPAS). COMPAS combines tools for statistical analysis and model selection with rapid population synthesis, allowing inferences to be made about the details of stellar and binary evolution.

Background :Cassiopeia A Supernoa Remnant Credit: NASA/JPL-Caltech/O. Krause (Steward Observatory)

COMPAS was initiated in order to explore the astrophysical implications of gravitational-wave observations. We are interested in understanding how the binary black holes discovered by LIGO could have formed, and how future observations could be best used to constrain our understanding of binary evolution. We are now including other observational signatures of binary evolution. Different observations provide different insights, and combining these leads to a more complete, concordance picture of binary astrophysics.

Our team

Contributors to COMPAS

Simon Stevenson, University of Birmingham

Simon Stevenson

The Boss

Ilya Mandel, University of Birmingham

Ilya Mandel

Black hole palaeontologist

Alejandro Vigna-Gomez, University of Birmingham

Alejandro Vigna-Gomez

Population synthesiser

Jim Barrett, University of Birmingham

Jim Barrett

Interpolation grand master

Coenraad Neijssel, University of Birmingham

Coenraad Neijssel

Stellar person

Sebastian Gaebel, University of Birmingham

Sebastian Gaebel

Binary counter

Ben Bradnick


Christopher Berry

Gravitational wave astronomer. Probably

Selma de Mink

Purveyor of wisdom

Stephen Justham

Protector of the realm

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