在β Pictoris盘中缺少分子
A Lecavelier des Etangs1, A Vidal-Madjar, A Roberge
1Institut d'Astrophysique de Paris, CNRS, 98 bis bld Arago, F-75014 Paris, France. lecaveli@iap.fr
Nature
|August 17, 2001
概括
这项研究研究了β Pictoris系统中的分子 (H2). 远紫外线观测显示H2柱密度非常低,这挑战了之前的红外发现,并表明H2不在直视线上.
科学领域:
- 天文学和天体物理学
- 行星科学 行星科学
- 天体化学是天体化学.
背景情况:
- 分子 (H2) 是恒星和行星形成区域的主要组成部分,但其直接检测具有挑战性.
- 以其碎片盘和推断的气态盘而闻名的β Pictoris系统已经显示了红外H2发射.
- 之前的研究表明,贝塔皮克托里斯盘中存在显著的气体成分,从红外观测中推断出H2.
研究的目的:
- 用远紫外光谱学研究贝塔皮克托里斯盘中分子 (H2) 的存在和丰富性.
- 为了调和红外推断H2与直接观测约束之间的差异.
- 为了确定磁盘中观察到的一氧化碳 (CO) 的来源.
主要方法:
- 获取和分析beta Pictoris恒星的远紫外线 (FUV) 光谱.
- 在FUV光谱中寻找暗示分子 (H2) 的吸收线.
- 测量一氧化碳 (CO) 吸收线,以确定CO/H2比率.
主要成果:
- 在β Pictoris的远紫外光谱中没有检测到分子 (H2) 吸收线.
- 确定了H2柱密度的一个严格的上限:N(H2) ≤10^18cm^-2.
- 测量了高的CO/H2比率 (> 6 x 10^-4) ,表明CO没有光解离.
结论:
- 在FUV中没有检测到H2,这表明它不在与恒星直接视线的磁盘中存在.
- 观察到的二氧化碳必须源于行星体的蒸发,否则它将在200年内被摧毁.
- 这项研究强调了多波长观测对于准确描述系外行星盘组成的重要性.
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