Evaluating the stability of atmospheric lines with HARPS
Evaluating the stability of atmospheric lines with HARPS
复制标题
使用 HARPS 评估大气线的稳定性
DOI：
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发表时间：
2010
期刊：
影响因子：
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通讯作者：
M. Mayor
中科院分区：
文献类型：
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作者：
P. Figueira;F. Pepe;C. Lovis;M. Mayor
上下文。当使用径向速度技术搜索太阳系外系统时，对高精度测量的需要意味着需要精确的波长校准。在红外领域，校准器的选择是一个特别重要的悬而未决的问题，该领域的精度和成就仍然不如光学领域。目标。我们研究了作为精确波长参考的大气谱线的长期稳定性，并分析了它们对不同大气和观测条件的敏感性。方法：研究方法。我们使用了HARPS的三颗明亮恒星TauCeti、μArae和eEri的档案数据，这些数据跨越了6年，包括在几个晚上进行的高阶测量。我们将这些数据与O2掩模互相关，并将径向速度和平分线的变化估计为1M/S的光子噪声水平。我们发现，这三个数据集的大地电力线在6年内稳定在10M/S(均方根)以下。我们还表明，径向速度变化可以用简单的大气模式来模拟，最终的精度为1-2m/S。尽管有大气现象，但6年来大气谱线的长期稳定度为10m/S。大气谱线可作为短时间尺度程序的波长参照物，不作任何改正，精度可达5m/S。如果使用所描述的简单大气模式对大气现象进行校正，则可以达到更高的精度，2m/S，这使得它即使在长时间尺度上也是一种非常有竞争力的方法。
Context. When searching for extrasolar systems using the radial velocity technique, the need for high-precision measurements implies that a precise wavelength calibration is required. The choice of the calibrator is a particularly important open question in the infra-red domain, where precision and achievements remain inferior to those in 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 archival data for three bright stars, TauCeti, μ Arae, and eEri, which span 6 years and include highcadence measurements performed over several nights. We cross-correlate this data with an O2 mask and evaluate both radial velocity and bisector variations to a photon noise level of 1m/s. Results. We find that the telluric lines in the three data-sets are stable down to 10m/s (rms) over the 6 years. We also show that the radial velocity variations can be modeled by simple atmospheric models, yielding a final precision of 1‐2m/s. Conclusions. The long-term stability of atmospheric lines was 10m/s over six years, in spite of atmospheric phenomena. Atmospheric lines can be used as awavelength reference for short timescale programs, yielding a precision of 5m/s without any correction. A higher precision, of 2m/s, can be reached if the atmospheric phenomena are corrected for using the simple atmospheric model described, making it a very competitive method even on long timescales.