DETECTION OF AN ATMOSPHERE AROUND THE SUPER-EARTH 55 CANCRI E
DETECTION OF AN ATMOSPHERE AROUND THE SUPER-EARTH 55 CANCRI E
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超级地球 55 CANCRI E 周围大气层的检测
DOI：
10.3847/0004-637x/820/2/99
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发表时间：
2015
期刊：
影响因子：
--
通讯作者：
ExoMol ExoLights
中科院分区：
文献类型：
--
作者：
A. Tsiaras;M. Rocchetto;I. Waldmann;O. Venot;R. Varley;G. Morello;M. Damiano;G. Tinetti;E. J. Barton;S. Yurchenko;J. Tennyson;ExoMol ExoLights
我们报告的分析两个新的光谱观测在近红外线的超级地球55 Cancri e，获得的WFC 3相机上的哈勃太空望远镜。巨蟹座55 e的轨道非常接近它的母星星，其表面的温度预计将远高于2000 K。由于巨蟹座55的亮度，观测是在扫描模式下获得的，采用了很长的扫描长度和很高的扫描速度。我们使用我们的专业管道，以考虑这些观测参数时，再加上仪器的几何失真引入的系统。我们以每次访问22 ppm的平均相对不确定性测量每个波长通道的过境深度，并发现偏离直线模型的调制，置信水平为6σ。这些结果表明，巨蟹座55 e被大气层包围，该大气层可能富含氢。我们的完全贝叶斯光谱检索代码，- 雷克斯，已经确定HCN是能够解释1.42和1.54 μm特征的最有可能的分子候选者。虽然需要在更宽的红外波长范围内进行额外的光谱观测来确认HCN的检测，但我们在这里讨论了这样一个结果的含义。我们的化学模型，与燃烧专家，表明相对较高的混合比的HCN可能是由一个高的C/O比。这一结果表明，这个超级地球是一个富含碳的环境，甚至比以前认为的更加奇特。
We report the analysis of two new spectroscopic observations in the near-infrared of the super-Earth 55 Cancri e, obtained with the WFC3 camera on board the Hubble Space Telescope. 55 Cancri e orbits so close to its parent star that temperatures much higher than 2000 K are expected on its surface. Given the brightness of 55 Cancri, the observations were obtained in scanning mode, adopting a very long scanning length and a very high scanning speed. We use our specialized pipeline to take into account systematics introduced by these observational parameters when coupled with the geometrical distortions of the instrument. We measure the transit depth per wavelength channel with an average relative uncertainty of 22 ppm per visit and find modulations that depart from a straight line model with a 6σ confidence level. These results suggest that 55 Cancri e is surrounded by an atmosphere, which is probably hydrogen-rich. Our fully Bayesian spectral retrieval code, ?> -REx, has identified HCN to be the most likely molecular candidate able to explain the features at 1.42 and 1.54 μm. While additional spectroscopic observations in a broader wavelength range in the infrared will be needed to confirm the HCN detection, we discuss here the implications of such a result. Our chemical model, developed with combustion specialists, indicates that relatively high mixing ratios of HCN may be caused by a high C/O ratio. This result suggests this super-Earth is a carbon-rich environment even more exotic than previously thought.
影响因子：
4.8
作者：
Barber, R. J.;Strange, J. K.;Tennyson, Jonathan
通讯作者：
Tennyson, Jonathan