巨大な恒星形成のために,コラムの最小密度は1gcm(-2) です
Mark R Krumholz1, Christopher F McKee
1Astrophysics Department, Princeton University, Princeton, New Jersey 08544, USA. krumholz@astro.princeton.edu
Nature
|February 29, 2008
まとめ
巨大な恒星は,高密度の柱 (少なくとも1gcm−2) のガス雲で形成され,断片化を防ぐ. この値は,巨大な恒星が形成される場所を説明し,銀河全体の恒星形成率の変動を暗示しています.
科学分野:
- 天文学と天体物理学について
- スター・フォーメーション
背景:
- 巨大な恒星は稀ですが,重要な宇宙エネルギー源であり,遠くの銀河の観測可能なビーコンです.
- 崩壊するガス雲の効率的な放射性冷却は,通常,断片化につながり,質量が低い星の形成を好む.
- 銀河の環境で大規模な恒星が形成されるのに必要な特定の条件は,ほとんど未定のままである.
研究 の 目的:
- 巨大な恒星の形成に必要なガス雲の重要な性質を決定する.
- 銀河の内部で巨大な恒星が形成される場所に影響を与える環境要因を調査する.
- 銀河盤の恒星の初期質量関数や放射プロファイルのような観測された現象を説明するために.
主な方法:
- 恒星形成ガス雲の崩壊の理論モデルの分析.
- 放射線による冷却と加熱のメカニズムが,断片化における役割を調査する.
- 雲柱の密度の値と観測された巨大な恒星群の性質を相関させる.
主要な成果:
- ガス雲の断片化と巨大な恒星の形成を避けるために,1gcm−2の最小柱密度値が特定されています.
- この値は,巨大な恒星群の特徴的な柱密度を説明する.
- この発見は,銀河円盤におけるH-αと紫外線放射の放射プロフィールの違いを調和させるものである.
結論:
- 特定されたコラム密度の値は,巨大な恒星形成を左右する重要な要因です.
- 恒星の初期質量関数 (IMF) は,銀河の環境によって変化することが予想されます.
- この値効果のために,特定の銀河の領域における恒星形成の速度は以前に過小評価されていたかもしれない.
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