AI 中文总结
该研究利用甚大望远镜的阿马宗斯光谱仪，通过模拟检测流程和新的贝叶斯CCF框架，评估对凌日系宜居行星生物特征气体的可探测性，给出不同气体探测所需凌日次数下限，还提及替代方法为生物特征搜索提供补充途径。
AI 中文摘要
对太阳系外生命的探索正处于转折点，从理论预测转向由下一代天文台进行观测。甚大望远镜（ELT）将搭载阿马宗斯高色散阶梯光谱仪（ANDES），专为可见到近红外高分辨率光谱优化。我们提出一个模拟检测流程，评估利用ANDES对凌日系宜居带岩石行星进行高分辨率透射光谱观测时二氧化碳、水以及生物特征气体氧气和甲烷的可探测性。假设为无云的现代类地大气，基于ANDES曝光时间计算器的噪声估计，根据最新的视场受限模式初步仪器设计对透射光谱进行建模。我们引入一个新颖的贝叶斯互相关函数（CCF）框架，纳入分子特定核和新的自回归模型以考虑CCF中的相关性。将我们的框架应用于18颗已知的潜在宜居凌日系系外行星，估计决定性探测（log₁₀B≥2.0）所需的凌日次数。发现水是最易探测的物种，对于TRAPPIST - 1行星在10 - 19次凌日可能探测到，对于LHS 1140 b在30次凌日可能探测到。二氧化碳、甲烷和氧气更难探测，所需凌日次数大约是水的1.5、3和4倍。这些估计是下限，假设了有利的观测条件、完美的去趋势处理和无系统误差，但仍意味着需要大规模观测活动。替代方法，如对附近非凌日系行星的反射光高色散日冕仪观测，可能为生物特征搜索提供有前景的补充途径。
英文摘要
The search for life beyond the Solar System is at a turning point, transitioning from theoretical predictions to observations enabled by next-generation observatories. The Extremely Large Telescope (ELT) will host the ArmazoNes high Dispersion Echelle Spectrograph (ANDES), optimized for visible-to-near-infrared high-resolution spectroscopy. We present a simulation--detection pipeline and evaluate the detectability of CO$_2$, H$_2$O, and the biosignature gases O$_2$ and CH$_4$ in high-resolution transmission spectroscopy of transiting habitable-zone rocky planets with ANDES. Assuming cloud-free, modern Earth-like atmospheres, we model transmission spectra using noise estimates from the ANDES Exposure Time Calculator, based on the latest preliminary instrument design in seeing-limited mode. We introduce a novel Bayesian cross-correlation function (CCF) framework that incorporates molecule-specific kernels and a new autoregressive model to account for correlations in the CCF. We apply our framework to 18 known potentially habitable transiting exoplanets and estimate the number of transits required for a decisive detection ($\log_{10} B \ge 2.0$). We find that H$_2$O is the most accessible species, with potential detections in 10-19 transits for the TRAPPIST-1 planets and 30 transits for LHS 1140 b. CO$_2$, CH$_4$, and O$_2$ are more difficult to detect, requiring approximately 1.5, 3, and 4 times as many transits as H$_2$O. These estimates are lower limits that assume favorable observing conditions, perfect detrending, and the absence of systematics, yet still imply large observing campaigns. Alternative approaches, such as reflected-light high-dispersion coronagraphy of nearby nontransiting planets, may offer a promising complementary route for biosignature searches.
Comments31 pages, 8 figures. Accepted by AAS journals
