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在本地30 Doradus星爆中存在大量的恒星
F R N Schneider1, H Sana2, C J Evans3
1Department of Physics, University of Oxford, Keble Road, Oxford OX1 3RH, UK.
概括
在30 Doradus地区的巨大的恒星形成显示了最近的衰退. 最初的质量函数 (IMF) 具有比Salpeter IMF预测的更多的高质量恒星,这表明大质量恒星形成的斜率较浅.
科学领域:
- 天文学与天体物理学
- 恒星进化
- 星系的形成
背景情况:
- 大麦哲伦云中的30 Doradus区域是研究早期宇宙中强烈恒星形成事件的关键类比.
- 了解初始质量函数 (IMF) 是理解恒星形成过程和星系演变的基础.
研究的目的:
- 为了研究30 Doradus地区最近的恒星形成历史.
- 为了确定30 Doradus内大质量恒星的初始质量函数 (IMF).
- 将观察到的IMF与标准的Salpeter IMF进行比较.
主要方法:
- 在30 Doradus区域观测了247颗质量超过15个太阳质量的恒星.
- 分析恒星光谱以确定个体恒星的质量和特性.
- 统计分析以得出IMF和恒星形成率.
主要成果:
- 30多拉杜斯的首次大规模恒星形成事件大约发生在800万年前.
- 在过去的100万年里, 恒星形成的速度似乎有所下降.
- 国际货币基金组织在30多拉杜斯的样本密度高达200个太阳质量.
- 与Salpeter IMF相比,IMF包含的恒星数量超过30太阳质量的恒星数量增加了32±12%.
- 在15-200太阳质量范围内,IMF功率定律指数为2.15±0.10,比Salpeter值2.35更浅.
结论:
- 30 Doradus的恒星形成历史表明最近的峰值和随后的衰退.
- 在30 Doradus中,大质量恒星的IMF偏离了标准的Salpeter预测,这表明高质量恒星的恒星形成过程存在差异.
- 这些发现提供了跨越不同环境和宇宙时代的恒星形成机制的普遍性.
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