在矮体不规则星系WLM中,低金属度云中的一氧化碳
Bruce G Elmegreen1, Monica Rubio, Deidre A Hunter
1IBM Research Division, T.J. Watson Research Center, 1101 Kitchawan Road, Yorktown Heights, New York 10598, USA. bge@us.ibm.com
Nature
|March 30, 2013
概括
在低金属度星系中检测到一氧化碳 (CO),挑战了关于恒星形成的先前假设. 这一发现表明,随着银河系的金属性降低,恒星形成和CO分子在分子云中变得越来越罕见.
科学领域:
- 天文学 天文学
- 天体物理学 天体物理学
- 宇宙恒星形成的宇宙恒星形成.
背景情况:
- 一氧化碳 (CO) 是恒星形成星际云的关键标记物.
- 在氧气丰富度低于太阳值20%的星系中没有检测到二氧化碳,这引发了关于低金属度环境中恒星形成的问题.
研究的目的:
- 为了研究低金属度星系中二氧化碳的存在.
- 了解二氧化碳在低金属度环境中的恒星形成中的作用.
主要方法:
- 利用了新的亚毫米观测.
- 分析了档案远红外观测结果.
- 在WLM星系中估计的云质量.
主要成果:
- 在WLM矮体不规则星系的两个区域检测到CO,其金属度为太阳值的13%.
- 估计云的质量超过10万个太阳质量.
- 发现CO分子气体分数为银河系值的3%.
结论:
- 恒星形成可以发生在没有丰富的CO的低金属度星系中.
- 形成恒星的核心和CO分子在分子云中变得越来越罕见,因为在小星系中金属性下降.
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