NGC 5253の非常に効率的な恒星形成は,おそらくストリームに供給された蓄積によるものです
J L Turner1, S C Beck2, D J Benford3
1Department of Physics and Astronomy, University of California, Los Angeles, Los Angeles, California 90095-1547, USA.
Nature
|March 20, 2015
まとめ
銀河の恒星形成は非効率ですが,NGC 5253の密集した,塵に満ちたガス雲は,50%以上の効率を示しています. この高い速度は,膨らむガスが燃料となり,古代の大量恒星群の形成を説明している可能性がある.
科学分野:
- 天文学 (astronomy) 天文学 (astronomy) とは,天文学 (astronomy) とは,天文学 (astronomy) とは,天文学 (astronomy) とは
- 天体物理学 天体物理学
- 銀河の進化 銀河の進化 銀河の進化
背景:
- 銀河の恒星形成効率は一般的に低いため,銀河の進化と星団の生存に影響を与えます.
- 古代球状星団の存在は,初期の宇宙におけるより高い恒星形成効率を示唆しています.
- 矮星銀河NGC 5253は,若くて巨大な恒星群をホストし,効率的な恒星形成のための潜在的なケーススタディを提供します.
研究 の 目的:
- 矮星銀河NGC 5253の巨大な若い恒星群に関連したガス雲の性質を調査する.
- この特定のガス雲内の恒星形成効率を決定するために.
- 高効率の恒星形成につながる可能性のある条件を理解する.
主な方法:
- 放射天文学を用いた一酸化炭素 (CO) のJ = 3→2の回転転移の検出.
- ガス雲の物理的性質の分析:温度,密度,および塵の含有量.
- ガスと塵の比率を,天の川の比率と比較した.
主要な成果:
- ガス雲の特徴は,高温,密度,極度の塵の含有量である.
- ガスと塵の比率は銀河の平均より著しく低く,おそらくは埋め込まれた星団からの塵の濃縮によるものです.
- この雲内の星形成効率は50%を超え,典型的な銀河の値の約10倍です.
結論:
- NGC 5253のガス雲で観測された高い恒星形成効率は,高密度と塵含有量を含むユニークな物理条件に起因する.
- 低いガスと塵の比率は,若い巨大な恒星群による濃縮を示唆しています.
- 流入するガス流 ("フォースフィーディング") は,この強化された星形成を駆動するメカニズムとして提案されており,初期の宇宙の条件を潜在的に反映しています.
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