銀河間媒体の金属性の大きな変動
Annalisa De Cia1, Edward B Jenkins2, Andrew J Fox3
1Department of Astronomy, University of Geneva, Versoix, Switzerland. annalisa.decia@unige.ch.
Nature
|September 9, 2021
まとめ
恒星間介質 (ISM) は有意な金属性の変化を示し,塵を補正した測定では,以前に想定したよりも低い量を示した. 高速の雲から集まったガスが 銀河の円盤にうまく混じり合っていないことを示しています
科学分野:
- 天文学と天体物理学
- 宇宙化学
背景:
- 恒星間介質 (ISM) は様々なガスと塵で構成されています.
- 銀河盤の金属性は,化学的進化モデルではしばしば均一であると考えられています.
- 塵の枯渇は,気体金属性の正確な測定を複雑にする.
研究 の 目的:
- 中性ISMの粉塵補正された金属性を決定する.
- 地元のISMにおける金属性の変動の範囲を調査する.
- ISMの化学的均一性に対する加熱ガスの影響を理解する.
主な方法:
- 紫外線吸収線スペクトロスコーピーを利用して,ISMの化学濃度を測定した.
- 固い粒に組み込まれた金属を考慮するために,適用された粉塵補正技術.
- ミルクウェイの25の星のデータを分析した.
主要な成果:
- ニュートラルなISMの金属性の変動が報告され,10倍に及ぶ.
- 標準偏差0.28デクスの平均金属度55±7%を発見した.
- 観測された地域は,太陽の金属度が17%以下で,重要な不均一性を示しています.
結論:
- ISMは化学的不均一性を示し,よく混合された太陽金属性ガス円盤の仮定に異議を唱える.
- 高速の雲を通した原始ガス蓄積は,これらの観測された金属性の変動の原因である.
- 低金属度加減ガスの不効率な混合は,同時代の星における金属度偏差を説明する可能性がある.
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