标题： 评估HARPS大气线的稳定性 显示英文标题

标题： Evaluating the stability of atmospheric lines with HARPS

摘要： 上下文：在通过径向速度技术搜索太阳系外系统时，精确的波长校准对于高精度测量是必要的。在红外波段，校准器的选择是一个特别重要的问题，因为这里的精度和利用程度仍落后于光学波段的成就。目标：我们研究大气线作为精确波长参考的长期稳定性，并分析它们对不同大气和观测条件的敏感性。方法：我们使用HARPS档案数据对三颗明亮恒星Tau Ceti、Mu Arae和Epsilon Eri进行研究，数据跨度为6年，并包含多个夜晚的高采样率测量。我们将这些数据与O2掩模进行交叉相关，并评估径向速度和双截距变化，精确到光子噪声为1 m/s。结果：我们发现三个数据集中的地出线在6年内稳定到10 m/s（均方根）。我们还表明，径向速度变化可以通过简单的大气模型来解释，最终精度为1-2 m/s。结论：尽管存在大气现象，大气线的长期稳定性在六年中测量为10 m/s。大气线可以作为短期项目的时间尺度波长参考，提供5 m/s的“即插即用”精度。如果通过文中描述的简单大气模型对大气现象进行校正，可以达到2 m/s的更高精度，使其在长时间尺度上也成为一种非常有竞争力的方法。 显示英文摘要

摘要： Context: In the search for extrasolar systems by radial velocity technique, a precise wavelength calibration is necessary for high-precision measurements. The choice of the calibrator is a particularly important question in the infra-red domain, where the precision and exploits still fall behind the achievements of the optical. Aims: We investigate the long-term stability of atmospheric lines as a precise wavelength reference and analyze their sensitivity to different atmospheric and observing conditions. Methods: We use HARPS archive data on three bright stars, Tau Ceti, Mu Arae and Epsilon Eri, spanning 6 years and containing high-cadence measurements over several nights. We cross-correlate this data with an O2 mask and evaluate both radial velocity and bisector variations down to a photon noise of 1 m/s. Results: We find that the telluric lines in the three data-sets are stable down to 10 m/s (r.m.s.) over the 6 years. We also show that the radial velocity variations can be accounted for by simple atmospheric models, yielding a final precision of 1-2 m/s. Conclusions: The long-term stability of atmospheric lines was measured as being of 10 m/s over six years, in spite of atmospheric phenomena. Atmospheric lines can be used as a wavelength reference for short-time-scales programs, yielding a precision of 5 m/s "out-of-the box". A higher precision, down to 2 m/s can be reached if the atmospheric phenomena are corrected for by the simple atmospheric model described, making it a very competitive method even on long time-scales.