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arXiv 1003.0541astro-ph.EPastro-ph.IM
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用HARPS评估大气线的稳定性

Evaluating the stability of atmospheric lines with HARPS

P. Figueira, F. Pepe, C. Lovis, M. Mayor

摘要:

内容:在利用视向速度技术寻找太阳系外星系的过程中,为了获得高精度的测量结果,必须进行精确的波长定标。定标器的选择在红外领域是一个特别重要的问题,在红外领域的精度和利用率仍然落后于光学的成就。目的:我们调查的长期稳定性的大气线作为一个精确的波长参考,并分析其灵敏度不同的大气和观测条件。研究方法:我们使用HARPS存档数据的三个明亮的恒星,鲸鱼座τ,Mu Arae和Eppolitan Eri,跨越6年,并包含高节奏的测量超过几个晚上。我们将这些数据与O2掩模相互关联,并评估径向速度和平分线变化,直至1 m/s的光子噪声。结果:三组数据中的大地电磁线在10 m/s(r.m.s.)以下是稳定的。在过去的6年里。我们还表明,径向速度的变化可以占简单的大气模型,最终精度为1-2米/秒。结论:尽管存在大气现象,但大气线的长期稳定性被测量为六年以上的10 m/s。大气线可用作短时间尺度程序的波长参考,产生5 m/s的“开箱即用”精度。如果通过所描述的简单大气模型对大气现象进行校正,则可以达到更高的精度(低至2 m/s),即使在长时间尺度上,它也是一种非常有竞争力的方法。

英文摘要:

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.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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