銀河系の内部ハロの年齢です
1Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, Maryland 21218, USA. jkalirai@stsci.edu
Nature
|June 9, 2012
まとめ
白い矮星は,天の川銀河の恒星集団の年代測定により明確な経路を提供します. この研究では,白矮星の質量を用いて,局所ハロ星の年齢を計算し,11.4 ± 0.7 億年前の恒星であることが判明しました.
科学分野:
- 天文学と天体物理学について
- 恒星の進化について
- 銀河の考古学について
背景:
- ミルクウェイ銀河は,膨らみ,円盤,ハローのような明確な構成要素で構成されています.
- 低質量星の正確な年代測定が困難であるため,恒星集団の組立の歴史を決定することは困難です.
- 白い矮星は,恒星の進化の残骸として,年齢を決定するためのより信頼性の高い方法を提供します.
研究 の 目的:
- 白い矮星を用いた恒星集団の年代測定のための新しい技術を開発する.
- 銀河系におけるローカル・フィールド・ハロ・スターの年齢を決定する.
- 銀河団の構成史に関する理解を深めること.
主な方法:
- 銀河系ハローの新生白矮星の観測.
- 球状星団メシア4の白矮星に関するアーカイブデータの分析.
- 白い矮星の質量分布の測定と恒星の進化モデルの逆転により,質量と年齢の関係が確立されました.
主要な成果:
- 白い矮星の最終質量と祖先質量と親集団の年齢を結びつける数学的関係が開発されました.
- ローカル・フィールド・ハロー・スターの年齢は,11.4 ± 0.7 億年と計算された.
- この年齢は,最も古い球状星団 (135億年) と一致するが,それより若い.
結論:
- 白い矮星は,銀河の構成要素の年代測定のための堅固なツールを提供します.
- 局所ハロー星の年齢は,銀河系形成を理解するための重要なデータポイントを提供します.
- ホロ・ホワイト・ダナスの将来の観測は,年齢の不確実性を軽減し,異なる銀河構造の形成時間を比較することができます.
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