二重中性子星融合におけるrプロセス核合成のスペクトル検出
E Pian1, P D'Avanzo2, S Benetti3
1INAF, Institute of Space Astrophysics and Cosmic Physics, Via Gobetti 101, I-40129 Bologna, Italy.
Nature
|November 3, 2017
まとめ
2つの中性子星の融合により 輝くキロノバが生まれ 金やプラチナのような重元素が生成されます この宇宙の爆発は GW170817と関連しており 核合成と宇宙の元素工場の 洞察力を提供しています
科学分野:
- 天体物理学
- 核物理学
- 宇宙学
背景:
- 中性子星の合併は 短いガンマ線爆発,重力波,キロノバを生成すると理論化されています.
- キロノバは,重元素合成 (rプロセス) で動いている一時的な光近赤外線源である.
- これまでのキロノヴァの証拠は限られており,2017年にわずかに明るくなったことが観察されました.
研究 の 目的:
- GW170817とGRB 170817Aに関連した明るいキロノヴァをスペクトル的に特定し,特徴づけること.
- キロノヴァ噴出物と その核合成物質の 物理的性質を理解する
- 重元素の生成における 中性子星の合併の役割を確認する
主な方法:
- 地上観測所からの一連のスペクトルを利用した.
- 紫外線から赤外線まで
- 観測されたスペクトル特徴とキロノヴァの理論モデルを比較した.
主要な成果:
- キロノバは急速に膨張するエジェクト (0.2c) を示し,1.5日間で50AUに達した.
- スペクトル特徴は,ダイナミックなエジェクタと風の領域で核合成によって生成された元素の存在を示した.
- ランタノイドを含む,太陽の0.03-0.05質量の物質が放出されました.
結論:
- 観測されたキロノヴァは 重元素の生成地として 中性子星の融合の強力な証拠を提供します
- この研究は,中性子星の合併に関連した 予測された現象を裏付けている.
- 金やプラチナなどの 希少元素の合成における キロノヴァの役割を 支持しています
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