Neutral Metals in the Atmosphere of HD 149026b
Neutral Metals in the Atmosphere of HD 149026b
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DOI：
10.3847/1538-3881/abdb25
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发表时间：
2021-01
期刊：
影响因子：
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通讯作者：
M. Ishizuka;H. Kawahara;S. K. Nugroho;Y. Kawashima;T. Hirano;M. Tamura
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文献类型：
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作者：
M. Ishizuka;H. Kawahara;S. K. Nugroho;Y. Kawashima;T. Hirano;M. Tamura
高色散光谱学的最新进展揭示了日面温度大于2000 K的高温超导体（UHJ）大气中存在蒸发的重金属和离子。利用斯巴鲁望远镜获得的高分辨率透射光谱的档案数据，我们在HD 149026 b中寻找中性金属，这是一个比UHJ更冷的热木星。通过去除恒星吸收和大地吸收，利用互相关技术，我们在大气中探测到了一个σ为4.4的中性钛和一个σ为2.8的中性铁的边缘信号。这是第一次在系外行星大气中探测到中性钛。在该温度范围内，钛倾向于形成氧化钛（TiO）。我们没有探测到TiO的任何信号，这表明大气中的C/O比高于太阳值。在温度低于UHJ的热彗星大气中探测到金属元素，将有助于了解热彗星的大气结构和形成历史。
Recent progress in high-dispersion spectroscopy has revealed the presence of vaporized heavy metals and ions in the atmosphere of hot Jupiters whose dayside temperature is larger than 2000 K, categorized as ultrahot Jupiters (UHJs). Using the archival data of high-resolution transmission spectroscopy obtained with the Subaru telescope, we searched for neutral metals in HD 149026b, a hot Jupiter cooler than UHJs. By removing stellar and telluric absorption and using a cross-correlation technique, we report a tentative detection of neutral titanium with 4.4σ and a marginal signal of neutral iron with 2.8σ in the atmosphere. This is the first detection of neutral titanium in an exoplanetary atmosphere. In this temperature range, titanium tends to form titanium oxide (TiO). The fact that we did not detect any signal from TiO suggests that the C/O ratio in the atmosphere is higher than the solar value. The detection of metals in the atmosphere of hot Jupiters cooler than UHJs will be useful for understanding the atmospheric structure and formation history of hot Jupiters.