Nome
Parâmetros atómicos para modelação de quilonovas

Código
2022.06730.PTDC

Entidade Beneficiária

LIP - Laboratório de Instrumentação e Física Experimental de Partículas

Sumário do Projecto

In this proposal we intend to make a relevant contribution to the questions "Where are the heaviestelements in nature produced? And can we identify an astrophysical signature of their production?"We know that light elements like hydrogen and helium are produced at the beginning of theuniverse, about a few minutes after the Big-Bang, and that heavier elements up to iron areproduced in nuclear fusion cycles inside stars. The mechanisms of production of elements heavierthan iron have also been developed for many decades. Half of the nuclei heavier than Iron can beproduced in stars from the asymptotic giant branch (AGB stars) through a neutron-capture processcalled s-process. The "s" comes from the slow capture rate of neutrons from seed nuclei, relative tothe competing reaction of β-decay. The other half, including thorium and uranium, cannot beproduced through this process Therefore, a more extreme process is required in which the rate ofneutron capture is higher than the timescale of beta-decay. This process is called rapid neutroncapture (or simply r-process).However, for such a process to occur, the environment must be extremely neutron-rich. For thatreason, core-collapse supernovae explosions were suggested as the main site for the production ofr-process elements. Yet, despite many years of research into this scenario, models and observationshave failed to show clear evidence that the r-process happens in core-collapse supernovae. On theother hand, the observation of a kilonova electromagnetic transient associated with thegravitational wave signal GW170817 provided the first direct indication that r-process elements areproduced in neutron-star mergers. Additional events are expected to be detected in the followingyears, representing a complete change of paradigm in r-process research, as for the first time we willbe confronted with direct observational data.To fully exploit such opportunity, it is fundamental to combine an improved description of nuclearand atomic parameters with sophisticated astrophysical simulations to provide accurate predictionof r-process nucleosynthesis yields and their electromagnetic signals to be confronted withobservational data. Tables of atomic parameters (level energies, excitation/ionization cross-sectionsand oscillator strengths between individual levels) needed to calculate stellar opacities and modelthe radiative transfer in the expanding ejecta have large gaps, or do not exist at all, for mostelements relevant for the r-process.In this project we will systematically calculate these atomic parameters for the different ionizationstages relevant at the density and temperature range found in the ejecta expansion in a kilonova.For this will use the FAC (Flexible Atomic Code) and MCDFGME (Multiconfiguration Dirac-Fock andGeneral Matrix Elements) codes that represent today the state of the art in atomic structurecalculations. The results will serve as input for modeling the luminosity curves of kilonovas beyondthe local thermal equilibrium (LTE) approximation. The incorporation of the data into the stellarradiative transfer codes will be done in collaboration with the Nuclear Astrophysics group of theGSI.This project will be led by LIP in collaboration with LIBPhys and GSI. The LIP and LIBPhys teammembers have solid experience in using these codes and have been collaborating for several yearson atomic structure calculations. The project aims at consolidating the collaboration recentlystarted with GSI in the scope of the European Research Council (ERC) funded KILONOVA project ledby G. Martínez-Pinedo.

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Suporte sob

Reforçar a investigação, o desenvolvimento tecnológico e a inovação

Região de Intervenção

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Financiamento

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Datas

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