| Seminar: | CPS Seminar |
| date: | 2026 July 24 (Fri) 13:00-14:30 |
| Room: | Online seminar (Zoom) |
| Speaker: | HARADA Naoto (Research Fellow, The University of Tokyo) |
| Title: | "Dynamical evolution of primordial binary during star cluster formation" |
| Abstract: |
Observational studies suggest that many stars are born in binary systems, making it crucial to clarify the primordial properties of binaries to understand the star formation process. Although properties such as the semi-major axis distribution of binaries in the field and star clusters have been observed in detail, they are affected by dynamical evolution within the cluster and do not necessarily reflect their primordial properties.
Then, we conducted self-consistent numerical simulations ranging from star cluster formation to their subsequent dynamical evolution, using the N-body/SPH simulation code ASURA+BRIDGE. We extended the code to handle cases where individual stars are born as binaries, and compared three models where stars are born as close binaries, wide binaries, and single stars. Our results show that while the close-binary formation model achieves a relatively high binary fraction, the wide-binary formation model experiences significant binary disruption due to close encounters, leading to a low binary fraction comparable to that of the single-star formation model. Regarding the dependence on the primary mass, differences in the binary fraction were particularly noticeable in low-mass stars, whereas the difference on the massive-star side was small. These results indicate that the observed properties of binaries are influenced by both their primordial properties and the dynamical evolution during the star cluster formation. |
| Keywords: | Star cluster formation, binary star, close encounter |
| Organizer: | SAITOH Takayuki |