The main idea of the project comes from the current state of research on the kilonova GW170817-GRB170817A-AT2017gfo, which marked the beginning of multi-messenger astrophysics. A comprehensive examination of this event, including methods of numerical calculations, data analysis and theoretical models, will complement and clarify the general physical mechanisms by identifying additional effects in the astrophysical system, as well as limitations that arise during the course of explosive processes in stars with the release of huge amounts of energy that can transform elemental composition on a galactic scale. The project is aimed at studying the problem of energy release in the s-barrier region during a kilonova explosion, which the ejected substance undergoes at the stage of enrichment with free neutrons. The project is an interdisciplinary study in nuclear astrophysics and brings together the expertise of researchers from the fields of nuclear physics, astrophysics and computer modeling.

Project tasks:
Task 1. Development of a software package for calculating the abundance of heavy elements involved in the creation of the termination point of s-process.
Subtask 1.1 Development of a software module for working with nuclear reaction databases ENDF/EXFOR.
Subtask 1.2 Development of a software module for constructing a burn up matrix and calculating its exponent.

Task 2. Calculation of the abundance of heavy elements in the region of the termination point of s-process.
Subtask 2.1 Assembly of software package modules with subsequent debugging to calculate the dynamics of nuclide transmutation.
Subtask 2.2 Calculation of the abundance of heavy elements included in the branches of cyclic reactions around the region of the termination point of s-process for the case of kilonova GW170817-GRB170817A-AT2017gfo.

Task 3. Calculation of the energy release of cyclic reactions for the case of kilonova GW170817-GRB170817A-AT2017gfo.
Subtask 3.1 Sensitivity analysis for cyclic reactions of the region of the termination point of s-process based on the developed software package.
Subtask 3.2 Calculation of energy release during cyclic reactions in the region of the termination point of s-process depending on the flux of free neutrons for the case of kilonova GW170817-GRB170817A-AT2017gfo, as well as potential candidates for the kilonova class.

Expected results: The main result of the research is a program code for calculating the abundance of heavy elements involved in the creation of the s-barrier, as well as for calculating the energy release when heavy elements capture a high-density neutron flux and the subsequent cycle of isotope formation and their spontaneous decay. As a result, we will be able to compare our calculations with observational data on the kilonova explosion event GRB170817A-GW170817-AT2017gfo, as well as give numerical estimates of the contribution of the s-barrier to the total energy release and the observed spectrum in different ranges of electromagnetic radiation.

Technology readiness level (TRL): Within the framework of the project, it is proposed to develop a software package for calculating the abundance of heavy elements involved in the creation of the s-barrier, to calculate the abundance of heavy elements in the area of the s-barrier, to calculate the energy release of cyclic reactions for the case of kilonova GW170817-GRB170817A- AT2017gfo. At the start of the project, the readiness of these technologies is at Level 0 – “Determining the possibility of developing a new technology.” It is expected that by the end of the project these technologies will be developed to Level 1 – “Assessing the impact of new technology”. The type of scientific and technical activity proposed by the project relates to fundamental research.

Conferences, seminars and training schools:
1. “19th Russbach School in Nuclear Astrophysics”, 3-9 March 2024, Russbach, Austria (in person) Ruslan Spassyuk – attendance, poster session, participation certificate

Specialists training:
1. Anarbek Daulet, Final project (in Russian language): “S-process in extragalactic astrophysical objects”. Defense date: June 2024. Degree awarded: Bachelor of Science in Physics. al-Farabi Kazakh National University. Scientific Supervisor: Yerlan Aimuratov

2. Bekzat Ultu, Final project (in Kazakh language): “R-process in extragalactic astrophysical objects”. Defense date: June 2024. Degree awarded: Bachelor of Science in Physics. al-Farabi Kazakh National University. Scientific Supervisor: Yerlan Aimuratov