Date & Time: 2024/December/16 17:00-18:00, Venue: Zoom TV Conference System. This is an informal seminar on the formation of stars and planets. We welcome anyone interested in the subject.
Abstract:
Astrophysical evidence suggests that the Sun was born near 5 kpc from the Galactic center, within the corotation radius of the Galactic bar, around 6–7 kpc. This presents challenges for outward migration due to the Jacobi energy constraint, preventing stars from easily overcoming the corotation barrier. In this study, we use test particle simulations to explore two possible migration pathways for the Sun: a "trapped" scenario, where the Sun's orbit was influenced by a slowing Galactic bar, and an "untrapped" scenario driven by dynamic spiral arms. Our results demonstrate that both mechanisms can explain how the Sun migrated from its birth radius (≈5 kpc) to its current orbital radius around 8.5–9 kpc. Furthermore, we investigate the environmental changes experienced by the Sun along these migration pathways, focusing on variations in radiation hazards and comet fluxes, which may have impacted planetary habitability. These findings highlight the dynamic nature of galactic habitability, emphasizing that the path a star takes within the Milky Way can significantly affect its surrounding environment and the potential for life. We propose a new concept of "Galactic habitable orbits," which accounts for evolving galactic structures and their effects on stellar and planetary systems. This work contributes to a deeper understanding of the solar system's migration and its implications for habitability within the Milky Way.
References: Baba et al. 2023, 2024
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Participants: 40, Affiliations:17
Participants list:
Hosei: P Tomoaki Matsumoto
Ibaraki: P Munetake Momose
ICRR: DA Jiro Shimoda
Kagoshima/NAOJ: Junichi Baba
Kagoshima: AP Hiroko Shinnaga
Kindai: Masayoshi Kiguchi
Kobe: DA Kenji Kurosaki
Kogakuin: AP Takayuki Muto
Kurume: L Masanobu Kunitomo
Kyushu: D1 Shimokawa, D1 Ayumu Shoshi, D1 Shingo Nozaki, M2 Mitsuki Omura
Nagoya: P Shu-ichiro Inutsuka, AP Hiroshi Kobayashi, D3 Kanta Kitajima, D2 Tomotaka Nishikawa, D1 Riona Yamada, D1 Izumi Seno, M2 Wataru Takahashi, M1 Kota Kobayashi, M1 Shusuke Utsumi, M1 Yuji Miko, B4 Yuki Tamaki
NAOJ: PD Yuji Matsumoto, PD Yoshiaki Misugi
Osaka: A Shinsuke Takasao, A Kohei Fukuda, PD Haruka Washinoue
Science Tokyo: PD Ryosuke Tominaga, D3 Yuya Fukuhara, D1 Shintaro Taira
Tohoku: PD Daisei Abe
U Cologne: PD Masato Kobayashi
UTokyo Komaba: P Takeru Suzuki, A Ryo Tazaki, PD Kensuke Kakiuchi
UTokyo: PD Naoto Harada, D1 Yuto Komichi, M2, Rumi Kodama
次回：2025/Feb./20 17:00-
連絡世話人：冨永遼佑（東京科学大学） tominaga.r.aa[at]m.titech.ac.jp