一个异常缺乏金属的球状星团的潮残留物
Zhen Wan1, Geraint F Lewis2, Ting S Li3,4,5,6
1Sydney Institute for Astronomy, School of Physics, The University of Sydney, Sydney, New South Wales, Australia.
Nature
|July 31, 2020
概括
这项研究发现了星流,这是一个球状星团的残余,其金属含量远远低于以前所知的
科学领域:
- 天文学与天体物理学
- 宇宙结构的形成
背景情况:
- 球状星团是星系中发现的古老,有重力结合的恒星系统.
- 已观察到一个"金属度地板",没有发现低于0.3-0.4%的球状星团.
- 这个底部可以表示球状星团形成的最小质量和最大红移.
研究的目的:
- 为了研究星流的特性, 一个动态冷的星流在银河系的光环.
- 确定流的祖先是否是一个球状星团, 并评估其金属性.
- 了解其金属性对球状星团形成和演变的影响.
主要方法:
- 使用南方星流光谱调查对星流进行光谱分析.
- 测量流中的化学 (金属) 含量,特别是铁 ([Fe/H]).
- 与已知的球状星团和理论模型进行比较.
主要成果:
- 星流的属性与一个球状星团的破坏遗迹一致.
- 河流具有极低的金属度 ([Fe/H] = -2.7),远低于已确定的金属度底线.
- 这一发现确定了迄今为止发现的最缺乏金属的球状星团原始体.
结论:
- 流的存在意味着有金属质的球状星团已经存在.
- 这些金属贫困的球状星团很可能在银河系的进化历史上被摧毁.
- 流的祖先与当今的球状星团不同.
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