在HD 209458bb附近的的起源
A Lecavelier des Etangs1, A Vidal-Madjar, J-M Désert
1CNRS, UMR 7095, Institut d'Astrophysique de Paris, 98bis boulevard Arago, F-75014 Paris, France. lecaveli@iap.fr
Nature
|November 14, 2008
概括
仅仅辐射压力就能解释在系外行星周围观察到的高速原子. 即使有恒星风,能量中性原子模型也需要显著的大气逃逸才能进行准确的观测.
科学领域:
- 外系行星科学 外系行星科学
- 天体物理学 天体物理学
- 行星大气层的行星大气层
背景情况:
- 以前的数值模拟表明,恒星风是必要的,以解释在系外行星过境期间的莱曼-α吸收.
- 霍尔姆斯特罗姆等人. 其他. 研究人员得出结论,仅仅辐射压力是不够的,需要对HD 209458b周围观察到的现象进行特殊的恒星风解释.
研究的目的:
- 调查辐射压力是否能够充分解释在系外行星过境期间观察到的高速原子.
- 在系外行星大气逃逸模型中重新评估特殊恒星风的必要性.
- 评估ENA模型所需的条件,特别是大气逃逸率.
主要方法:
- 使用数值模拟来建模恒星辐射与系外行星大气的相互作用.
- 模拟的重点是辐射压力对HD 209458b附近的原子的影响.
- 模拟结果与莱曼-α吸收的观测数据的比较.
主要成果:
- 这项研究表明,单独作用的辐射压力可以成功地重现观察到的高速原子.
- 这一发现与得出的结论相矛盾,即辐射压力不足,需要特殊的恒星风.
- 即使涉及到恒星风,ENA模型也需要相当大的行星大气逃逸率,与以前的估计相比.
结论:
- 辐射压力是驱动在系外行星过境期间观察到的高速原子的可行和潜在的主导机制.
- 可以减少对复杂的恒星风模型的依赖,简化观察到的现象的解释.
- 进一步的研究应该考虑辐射压力,恒星风和大气逃逸之间的相互作用,以塑造系外行星大气.
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