在NGC 5253中高效的恒星形成,可能是源于流的积累
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
概括
星系中的恒星形成是低效的,但NGC 5253中的密集,尘埃覆盖的气体云显示了50%以上的效率. 这种高速率可能是由气体膨胀所推动的,这解释了古代大质量恒星团的形成.
科学领域:
- 天文学 天文学
- 天体物理学 天体物理学
- 银河系的进化 银河系的进化
背景情况:
- 星系中的恒星形成效率通常很低,影响星系进化和恒星团的生存.
- 古代球状星团的存在表明,早期宇宙中的恒星形成效率更高.
- 矮星系NGC 5253拥有一个年轻,巨大的恒星团,为高效的恒星形成提供了潜在的案例研究.
研究的目的:
- 为了研究与矮星系NGC 5253中的一个巨大的年轻恒星团相关的气体云的特性.
- 为了确定这个特定气体云内的恒星形成效率.
- 了解可能导致高效恒星形成的条件.
主要方法:
- 使用射电天文学检测一氧化碳 (CO) 的J = 3→2旋转转变.
- 分析气体云的物理特性:温度,密度和尘埃含量.
- 将气体与尘埃的比率与银河系的比较.
主要成果:
- 气体云的特点是高温,密度和极端的灰尘含量.
- 气体与尘埃的比率明显低于银河系平均值,这可能是由于嵌入星团中的尘埃丰富.
- 这个星云中的恒星形成效率超过50%,大约是典型银河系值的十倍.
结论:
- 在NGC 5253的气体云中观察到的高恒星形成效率归因于其独特的物理条件,包括高密度和尘埃含量.
- 低的气体与尘埃的比率表明,这颗年轻,巨大的恒星团的丰富.
- 推测,入的气体流 ("强力养") 是推动这种增强恒星形成的机制,可能反映了早期宇宙的条件.
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