AI 中文总结
研究旨在解决系外行星大气甲烷光学光谱数据限制问题，通过观测泰坦光学光谱生成高分辨率甲烷谱线表，构建模板用于高分辨率互相关光谱研究，首次在泰坦和木星大气中检测到甲烷，为系外行星甲烷探测奠定基础。
AI 中文摘要
系外行星大气特征的确定严重依赖分子光谱数据。尽管努力获取用于系外行星大气化学特征描述的综合光谱库，但仍存在巨大差距，尤其是对于大分子和高光谱分辨率下的高频区域。甲烷的光学光谱就是一个关键例子。甲烷是系外行星大气特征描述的关键物种及可能的生物特征，但此前在光学波长下获取高分辨率谱线表极具挑战。为解决这一光谱数据限制，我们用VLT - ESPRESSO以迄今最高光谱分辨率观测了以甲烷吸收为主的泰坦光学光谱，生成了一个经验性的低温高分辨率（R约190000）光学波长甲烷谱线表，并利用它构建了适用于高分辨率互相关光谱研究的模板，首次在泰坦和木星大气中通过光学高分辨率光谱对甲烷进行了高分辨率互相关光谱检测。这项工作为通过当前和未来地基高分辨率光学光谱仪利用高分辨率互相关光谱在系外行星大气中寻找甲烷奠定了基础。
英文摘要
Exoplanet atmosphere characterization heavily relies on molecular spectroscopic data. Despite efforts to obtain comprehensive spectral libraries for the chemical characterization of exoplanet atmospheres, large gaps remain, particularly for larger molecules and higher frequencies at high spectral resolution. One key example is the methane (CH4) optical spectrum. CH4, the simplest hydrocarbon, is a crucial species for exoplanet atmosphere characterization and a possible biosignature. However, until now, high-resolution linelists at optical wavelengths for CH4 have been very challenging to obtain either experimentally or computationally, leaving the high resolution spectrum of CH4 uncharacterised across most of the visible spectrum. This restricts exploration of CH4 absorption in the optical regime, as upcoming instruments such as ELT-ANDES and VLT-RISTRETTO will start probing the atmospheres of ever smaller exoplanets in optical wavelengths. To address this spectroscopic data limitation, we observed Titan's optical spectrum, dominated by CH4 absorption, at the highest spectral resolution to date with VLT-ESPRESSO. From it, we produced an empirical, low-temperature high-resolution (R ~ 190000) linelist of CH4 in optical wavelengths which we present here, with thousands of previously unidentified lines. We employ this CH4 linelist (RRS-2026) to build a template suitable for high resolution cross-correlation spectroscopy (HRCCS) studies, a first for CH4 in optical wavelengths. With this new linelist, we performed the first HRCCS detection of CH4 in the atmospheres of Titan and Jupiter using optical high resolution spectra. This work sets the stage for the search for CH4 in exoplanet atmospheres through HRCCS with current and future ground-based high-resolution optical spectrographs, showcasing how Solar System observations provide useful products for exoplanet research.
CommentsAccepted for publication in the Astrophysical Journal Supplement Series
