HEAVYMETAL is a European Research Council–funded project investigating how the heaviest elements in the universe are forged in neutron star mergers. The project combines hydrodynamic simulations of mergers, nuclear network calculations of nucleosynthesis, atomic-structure theory and laboratory measurements of heavy-element opacities, and observational analysis of kilonovae — bringing these threads together to determine which elements are produced, in what abundance, and under which conditions.

The science

About half of the elements heavier than iron are made by the so-called rapid neutron capture, or r-process. The conditions required — extreme neutron fluxes on millisecond timescales — are thought to occur in compact-object mergers, and the 2017 multimessenger detection of GW170817 / AT2017gfo confirmed that neutron star mergers do indeed synthesise heavy elements. The detailed pathways, however — which elements are made in what proportions, under which dynamical and thermal conditions, and on which timescales — remain open questions, and answering them is the goal of HEAVYMETAL.

The project brings together four complementary lines of work:

• Hydrodynamic simulations of neutron star mergers and the dynamics of the resulting ejecta
• Nuclear network calculations of r-process nucleosynthesis
• Atomic-structure calculations and laboratory measurements of opacities for heavy elements
• Observational analysis and spectral modelling of kilonova light curves and spectra

The consortium

HEAVYMETAL is an ERC Synergy collaboration, led by four Principal Investigators across four European institutions:

• Darach Watson — University of Copenhagen (UCPH), coordinator
• Andreas Bauswein — GSI Helmholtzzentrum für Schwerionenforschung (GSI)
• Stuart Sim — The Queen’s University Belfast (QUB)
• Padraig Dunne — University College Dublin (UCD)

The four PIs lead complementary research teams across observational astronomy, hydrodynamic simulation, nuclear physics, and atomic structure.

See the members page for the full team, and the news and meetings pages for recent results and consortium activities.

Funding

HEAVYMETAL is funded by the European Research Council under grant agreement No. 101071865. Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or the European Research Council. Neither the European Union nor the granting authority can be held responsible for them.