Testing the Detectability of Extraterrestrial O2 with the Extremely Large Telescopes Using Real Data with Real Noise
Testing the Detectability of Extraterrestrial O2 with the Extremely Large Telescopes Using Real Data with Real Noise
复制标题
使用真实数据和真实噪声测试超大望远镜对外星氧气的可探测性
DOI：
10.3847/2041-8213/aafa1f
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发表时间：
2019
期刊：
影响因子：
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通讯作者：
I. Snellen
中科院分区：
文献类型：
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作者：
Dilovan B. Serindag;I. Snellen
未来的极大望远镜（ELT）预计将成为使用高色散光谱探测太阳系外行星大气层的强大工具，有可能探测到在附近的晚型恒星过境的类地行星中的分子氧。到目前为止，模拟集中在使用合成噪声分布的氧气光学7600 Å A波段上。在这封信中，我们建立在以前的工作，预测分子氧在附近的可探测性，温带行星使用档案，时间序列数据Proxima Centauri从高色散紫外线和视觉Echelle光谱仪（UVES）ESO的超大望远镜（VLT）。最明亮的凌日M矮星预计比Proxima暗25倍，这一因素类似于VLT和未来ELT之间的聚光能力差异。通过向UVES数据中注入合成氧透射信号，可以在存在具有真实的噪声特性的真实的数据的情况下研究可探测性。校正的Proxima光谱的相对较低的吞吐量（0.4%），以假定的20%的吞吐量为高色散光谱仪在欧洲ELT，我们发现，分子氧签名的地球孪生过境附近（d 7 pc）M5 V星星可以检测到在20-50过境（共70-175小时的观测时间）。这一估计，使用更现实的模拟，接近以前的预测。增加仪器吞吐量的新概念可以进一步减少需要进行此类观察的时间跨度。
The future extremely large telescopes (ELTs) are expected to be powerful tools to probe the atmospheres of extrasolar planets using high-dispersion spectroscopy, with the potential to detect molecular oxygen in Earth-like planets transiting nearby late-type stars. So far, simulations have concentrated on the optical 7600 Å A-band of oxygen using synthetic noise distributions. In this Letter, we build upon previous work to predict the detectability of molecular oxygen in nearby, temperate planets by using archival, time-series data of Proxima Centauri from the high-dispersion Ultraviolet and Visual Echelle Spectrograph (UVES) on ESO’s Very Large Telescope (VLT). The brightest transiting M-dwarfs are expected to be about 25 times fainter than Proxima, a factor that is similar to the difference in light-gathering power between the VLT and the future ELTs. By injecting synthetic oxygen transmission signals into the UVES data, the detectability can be studied in the presence of real data with real noise properties. Correcting for the relatively low throughput (∼4%) of the Proxima spectra to an assumed 20% throughput for a high-dispersion spectrograph on the European ELT, we find that the molecular oxygen signature of an Earth-twin transiting a nearby (d ≈ 7 pc) M5V star can be detected in 20–50 transits (a total of 70–175 hr of observing time). This estimate, using more realistic simulations, is close to previous predictions. Novel concepts that increase the instrumental throughput can further reduce the time span over which such observations need to be taken.