Seeing above the clouds with high-resolution spectroscopy
Seeing above the clouds with high-resolution spectroscopy
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用高分辨率光谱仪观察云层之上
DOI：
10.1093/mnras/staa2424
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发表时间：
2020
影响因子：
4.8
通讯作者：
R. K. Webb
中科院分区：
文献类型：
--
作者：
S. Gandhi;M. Brogi;R. K. Webb
在过去的十年中，地面高分辨率多普勒光谱仪（HRS）已经在过境和非过境的热彗星中探测到了许多物种，并且非常适合于温暖的海王星和超级地球的大气特征。这些较冷和较小的系外行星中有许多在低分辨率近红外观测中显示出多云的大气，这使得对化学物种的限制变得困难。我们研究了HRS如何改善这些考虑到其灵敏度的光谱线核心，探测更高的海拔以上的云。我们模拟了暖海王星GJ~3470~B的透射光谱，并用CARMENES、GIANO和SPIRou摄谱仪测定了H$_2$O的可探测性。我们还模拟了另一个温暖的海王星GJ~436~B在云顶压力和H$_2$O丰度范围内的光谱网格。我们表明，H$_2$O是可检测的两颗行星与适度的观测时间和高H$_2$O丰度高云甲板简并与HRS被打破。然而，有意义的限制丰度和云顶压力，只有在高金属丰度的情况下是可能的。我们还证明了从GJ~436~B的多云模式中探测CH $_4 $和NH $_3 $是可能的。最后，我们展示了如何地球的透射光谱的存在下，阻碍了检测H$_2$O的最多云的情况下，大地吸收重叠的最强的H$_2$O功能。HRS对分子种类的可能限制可用于成分分析，并在未来研究此类行星的化学多样性。
In the last decade ground based high resolution Doppler spectroscopy (HRS) has detected numerous species in transiting and non-transiting hot Jupiters, and is ideally placed for atmospheric characterisation of warm Neptunes and super Earths. Many of these cooler and smaller exoplanets have shown cloudy atmospheres from low resolution near infrared observations, making constraints on chemical species difficult. We investigate how HRS can improve on these given its sensitivity to spectral line cores which probe higher altitudes above the clouds. We model transmission spectra for the warm Neptune GJ~3470~b and determine the detectability of H$_2$O with the CARMENES, GIANO and SPIRou spectrographs. We also model a grid of spectra for another warm Neptune, GJ~436~b, over a range of cloud-top pressure and H$_2$O abundance. We show H$_2$O is detectable for both planets with modest observational time and that the high H$_2$O abundance-high cloud deck degeneracy is broken with HRS. However, meaningful constraints on abundance and cloud-top pressure are only possible in the high metallicity scenario. We also show that detections of CH$_4$ and NH$_3$ are possible from cloudy models of GJ~436~b. Lastly, we show how the presence of the Earth's transmission spectrum hinders the detection of H$_2$O for the most cloudy scenarios given that telluric absorption overlaps with the strongest H$_2$O features. The constraints possible with HRS on the molecular species can be used for compositional analysis and to study the chemical diversity of such planets in the future.
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影响因子：
4.8
作者：
Arazi Pinhas;N. Madhusudhan;S. Gandhi;R. MacDonald
通讯作者：
Arazi Pinhas;N. Madhusudhan;S. Gandhi;R. MacDonald
使用 ELT 进行高分辨率光谱和高对比度成像：在 Proxima b 中寻找 O2
影响因子：
4.8
作者：
Hawker G
通讯作者：
Hawker G
影响因子：
4.8
作者：
S. Cabot;N. Madhusudhan;George A Hawker;S. Gandhi
通讯作者：
S. Cabot;N. Madhusudhan;George A Hawker;S. Gandhi
HyDRA-H：同时混合检索系外行星发射光谱
DOI：
10.3847/1538-3881/ab4efc
发表时间：
2019
期刊：
The Astronomical Journal
影响因子：
--
作者：
Gandhi S
通讯作者：
Gandhi S