Explaining Common Envelope Evolution and Dynamics in binary stellar systems

Projektinformationen

ExCEED

ID Finanzhilfevereinbarung: 101096243

DOI

10.3030/101096243

EK-Unterschriftsdatum 27 Juli 2023

Startdatum 1 Januar 2024

Enddatum 31 Dezember 2028

Finanziert unter

• European Research Council (ERC)

Gesamtkosten

€ 2 500 000,00

EU-Beitrag

€ 2 500 000,00

Koordiniert durch

RUPRECHT-KARLS-UNIVERSITAET HEIDELBERG
Germany

Periodic Reporting for period 1 - ExCEED (Explaining Common Envelope Evolution and Dynamics in binary stellar systems)

Berichtszeitraum: 2024-01-01 bis 2026-06-30

Zusammenfassung vom Kontext und den Gesamtzielen des Projekts

A thorough understanding of stellar evolution is key to nearly any branch of astrophysics. The majority of stars evolves in binary or multiple systems and interactions often occur between their components. Such dynamical interaction phases are pivotal for the fate of the system and its constituents, but they elude classical stellar modeling. Common-envelope phases, in which a compact companion spirals into the envelope of a giant primary star, are the glaring gaps in our knowledge and pose one of the last unsolved fundamental problems to stellar astrophysics.

The ExCEED project breaks new ground by developing a strategy to reach a comprehensive understanding of common-envelope evolution. It combines leading three-dimensional magnetohydrodynamic moving-mesh simulations with innovative models of physical processes to decipher the dynamical interaction between the stellar cores and the envelope material. On this basis, the post-common envelope evolution is explored by consistently linking to classical one-dimensional models. Predictions for astronomical observables are derived and a faithful effective prescription for representing common-envelope phases in binary stellar evolution and population synthesis calculations is constructed.

The new understanding of common-envelope evolution provided by the ExCEED project marks a breakthrough in stellar astrophysics and has implications beyond this field. ExCEED finally settles the long- standing questions of the mechanism of envelope ejection and the orbital separation of the post-common envelope remnant binary system. This allows to understand the formation of the targets of gravitational-wave astronomy that holds promise to solve problems of fundamental physics, the progenitors of Type Ia supernovae, and many other astrophysical events.

Arbeit, die ab Beginn des Projekts bis zum Ende des durch den Bericht erfassten Berichtszeitraums geleistet wurde, und die wichtigsten bis dahin erzielten Ergebnisse

During the reporting period, the theoretical framework of the project was developed and the corresponding computational models were designed and implemented. Simulation setups were implemented into the AREPO code. These were tested and first numerical results were obtained, some showing consistency with expectations and others revealing non-trivial behaviors. The planned milestones were achieved, and the established theory–simulation pipeline provides a solid basis for the next phase of the project. As outlined in the work plan, the focus of this first phase of the ExCEED project was on method developments, in particular the implementation of radiative transfer and moving boundary conditions into the common-envelope simulations and on improving the initial models.

Fortschritte, die über den aktuellen Stand der Technik hinausgehen und voraussichtliche potenzielle Auswirkungen (einschließlich der bis dato erzielten sozioökonomischen Auswirkungen und weiter gefassten gesellschaftlichen Auswirkungen des Projekts)

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