講演情報
[O13-P09]Cosmic Alchemy: Element Formation in Neutron Star Mergers
From the Birth of Stars to the Origin of Heavy Elements
*Hijiri Tawada1 (1. Otsu Municipal Ojiyama Junior High School, Certified NPO Biwako Trust)
キーワード：
Neutron star merges、Kilonova、r-process nucleosynthesis、Heavy elements、Element formation
Where do the elements around us come from? Hydrogen, helium, and small amounts of lithium were produced in the Big Bang. Elements from hydrogen up to iron are mainly formed through nuclear fusion inside stars. However, elements heavier than iron are created in extreme environments such as supernova explosions and binary neutron star mergers.
This study focuses on the production of heavy elements in binary neutron star mergers, often referred to as “cosmic alchemy.” In 2017, a binary neutron star merger was observed, and both gravitational waves and a phenomenon known as a kilonova were detected. This observation was a major breakthrough, providing strong evidence for the formation of heavy elements.
In a kilonova, a process called the r-process occurs, in which a large number of neutrons are rapidly captured by atomic nuclei. This leads to the formation of heavy elements such as gold and platinum.
To make the origin of elements easier to understand, this study uses a color-coded periodic table to explain which elements are produced by different processes. The table categorizes elements based on their formation mechanisms, such as nuclear fusion inside stars, supernova explosions, and binary neutron star mergers. However, the boundaries between these processes are still an active area of research.
This study also examines the formation of neutron stars and their relationship with black holes, which are formed through similar processes. When a star with a mass more than about eight times that of the Sun produces iron through nuclear fusion, the iron core becomes stable and can no longer support outward pressure. As a result, the star collapses under its own gravity and triggers a supernova explosion. Both neutron stars and black holes are born from such explosions, making them in a sense “siblings.” The key difference lies in their mass: depending on it, either a neutron star or a black hole is formed.
There are also important differences between these two objects. Neutron stars have a solid surface, whereas black holes do not. Instead, black holes have a boundary called the event horizon, from which not even light can escape.
Furthermore, this study uses simulation software (Universe Sandbox) to recreate the process of binary neutron star mergers and to visually understand kilonova. Although simplified, these simulations help illustrate the dramatic nature and extreme conditions of neutron star mergers.
As a supplementary part of this research, astronomical observations were conducted using the smart telescope Seestar S50. Observations of the Sun provided insights into stellar activity, while observations of the Orion Nebula, a representative star-forming region, demonstrated the early stages of stellar evolution.
Through this study, I aim to explain the mechanisms of cosmic element formation in an intuitive and visual way, highlighting the crucial role of binary neutron star mergers in producing heavy elements via the r-process.
This study focuses on the production of heavy elements in binary neutron star mergers, often referred to as “cosmic alchemy.” In 2017, a binary neutron star merger was observed, and both gravitational waves and a phenomenon known as a kilonova were detected. This observation was a major breakthrough, providing strong evidence for the formation of heavy elements.
In a kilonova, a process called the r-process occurs, in which a large number of neutrons are rapidly captured by atomic nuclei. This leads to the formation of heavy elements such as gold and platinum.
To make the origin of elements easier to understand, this study uses a color-coded periodic table to explain which elements are produced by different processes. The table categorizes elements based on their formation mechanisms, such as nuclear fusion inside stars, supernova explosions, and binary neutron star mergers. However, the boundaries between these processes are still an active area of research.
This study also examines the formation of neutron stars and their relationship with black holes, which are formed through similar processes. When a star with a mass more than about eight times that of the Sun produces iron through nuclear fusion, the iron core becomes stable and can no longer support outward pressure. As a result, the star collapses under its own gravity and triggers a supernova explosion. Both neutron stars and black holes are born from such explosions, making them in a sense “siblings.” The key difference lies in their mass: depending on it, either a neutron star or a black hole is formed.
There are also important differences between these two objects. Neutron stars have a solid surface, whereas black holes do not. Instead, black holes have a boundary called the event horizon, from which not even light can escape.
Furthermore, this study uses simulation software (Universe Sandbox) to recreate the process of binary neutron star mergers and to visually understand kilonova. Although simplified, these simulations help illustrate the dramatic nature and extreme conditions of neutron star mergers.
As a supplementary part of this research, astronomical observations were conducted using the smart telescope Seestar S50. Observations of the Sun provided insights into stellar activity, while observations of the Orion Nebula, a representative star-forming region, demonstrated the early stages of stellar evolution.
Through this study, I aim to explain the mechanisms of cosmic element formation in an intuitive and visual way, highlighting the crucial role of binary neutron star mergers in producing heavy elements via the r-process.