在原行星盘中大颗粒尘埃的辐射压力混合
1Physics Department, University of Split, Nikole Tesle 12, 21000 Split, Croatia. vinkovic@pmfst.hr
Nature
|May 16, 2009
概括
年轻恒星的尘埃盘中含有大型的晶粒. 红外辐射将更大的颗粒从内部盘中提升,允许向外运输到更冷的区域,以便最终重新进入.
科学领域:
- 天文学 天文学
- 天体物理学 天体物理学
- 行星科学 行星科学
背景情况:
- 年轻的恒星物体拥有由无形的亚微米粒组成的灰尘积聚盘.
- 观测显示彗星,石和年轻恒星光谱中的大晶粒,表明高温处理 (> 1,000 K).
- 现有的运输这些加工谷物的模型从热的内部盘到冷的外部区域涉及复杂的混合机制与潜在的问题.
研究的目的:
- 研究一种用于在原行星盘内运输加工谷物的新机制.
- 为了解释灰尘磁盘在较冷的区域存在大的晶粒.
主要方法:
- 利用基于来自尘土的磁盘的红外辐射压力的理论建模.
- 通过红外辐射压力模拟较大的粉尘颗粒 (>1微米) 的升空和向外运输.
- 分析谷物由于辐射压力支不足而重新进入较冷的磁盘区域.
主要成果:
- 来自尘埃覆盖的磁盘的红外辐射可以使较大的颗粒 (>1微米) 从内部磁盘中浮出.
- 恒星辐射的压力将这些悬浮的颗粒推向磁盘上方的外部.
- 颗粒在更大的半径下降回磁盘中,温度较低,辐射压力不足以持续支.
结论:
- 涉及红外辐射压力的新机制解释了冷盘区域中加工的谷物的存在.
- 这一过程涉及谷物升空和向外运输,可能在大多数年轻恒星物体和年轻棕矮星中普遍存在.
- 这些发现挑战了以前的假设,即大规模混合是热变化的尘埃颗粒的唯一运输机制.
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