Infrared Transmission Spectra for Extrasolar Giant Planets
Infrared Transmission Spectra for Extrasolar Giant Planets
复制标题
太阳系外巨行星的红外传输光谱
DOI：
10.1086/510716
复制
发表时间：
2006
期刊：
影响因子：
--
通讯作者：
Y. Yung
中科院分区：
文献类型：
--
作者：
G. Tinetti;M. Liang;A. Vidal;D. Ehrenreich;A. Lecavelier des Etangs;Y. Yung
在目前已知的经过母星的热彗星中，HD 189733 b和HD 209458 b是最好的候选者，因为它们的行星密度、轨道参数、母星星距离和亮度都有综合特征。在这里，我们模拟这两颗行星的透射光谱在他们的主要过境在和平号，我们目前的光谱的大气热性质，分子丰度和C/O比的变化的敏感性研究。我们的模型预测，在MIR热蒸发器上吸收的主要物种是水蒸气和一氧化碳，它们的相对丰度由C/O比决定。由于与分子丰度相比，温度分布在热彗星的透射光谱中起着次要作用，因此未来在这些物体的MIR中进行的主要过境观测可能会提供对太阳系外巨行星大气化学的深入了解。我们在这里发现，在无云大气中由水蒸气和一氧化碳引起的吸收特征足够深，可以被现在和未来一代的天基天文台观测到，如斯皮策太空望远镜和詹姆斯韦伯太空望远镜。我们根据这些望远镜的能力讨论我们的结果。
Among the hot Jupiters known to date that transit their parent stars, the two best candidates to be observed with transmission spectroscopy in the mid-infrared (MIR) are HD 189733b and HD 209458b, due to their combined characteristics of planetary density, orbital parameters, and parent star distance and brightness. Here we simulate transmission spectra of these two planets during their primary transit in the MIR, and we present sensitivity studies of the spectra to the changes of atmospheric thermal properties, molecular abundances, and C/O ratios. Our model predicts that the dominant species absorbing in the MIR on hot Jupiters are water vapor and carbon monoxide, and their relative abundances are determined by the C/O ratio. Since the temperature profile plays a secondary role in the transmission spectra of hot Jupiters compared to molecular abundances, future primary transit observations in the MIR of those objects might offer insight on extrasolar giant planet atmospheric chemistry. We find here that the absorption features caused by water vapor and carbon monoxide in a cloud-free atmosphere are deep enough to be observable by the present and future generation of space-based observatories, such as Spitzer Space Telescope and James Webb Space Telescope. We discuss our results in light of the capabilities of these telescopes.