The Homogeneous Study of Transiting Systems (HoSTS) - II. The influence of the line list on stellar parameters
The Homogeneous Study of Transiting Systems (HoSTS) - II. The influence of the line list on stellar parameters
复制标题
传输系统的同质研究 (HoSTS) - II。
DOI：
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发表时间：
2017
期刊：
影响因子：
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通讯作者：
Y. G. M. Chew
中科院分区：
文献类型：
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作者：
A. Doyle;B. Smalley;F. Faedi;D. Pollacco;Y. G. M. Chew
使用高分辨率、高信噪比的恒星光谱是通过光谱学确定最准确和最精确的恒星大气参数所必需的。这对于确定系外行星的基本参数尤其重要，这些参数直接取决于恒星的性质。然而，在分析这些光谱时可以采用不同的技术，这将影响结果。这些措施包括进行相对于太阳值的丰度分析，以消除原子数据中的不确定性，以及将表面重力(Logg)固定为外部值，例如来自星震学的值。所用线条的选择也会影响结果。在这篇文章中，我们研究了一组FGK星的微分分析和对数g的确定，这些星已经有了从外部方法已知的精确的基本参数。我们发现，与实验室线表相比，差分线表给出的参数稍微更准确一些，但是实验室线表仍然给出了稳健的参数。我们还发现，固定对数g并不能改善光谱参数。我们研究了谱线选择对恒星参数的影响，发现所用谱线的选择对参数有很大的影响。特别是，移除某些低激发势线可以使TJeff改变高达50K。对于未来的主办方论文，我们将使用太阳微湍流值为1公里/S的差分线表，我们不会将对数g固定为外部值。
The use of high resolution, high signal-to-noise stellar spectra is essential in order to determine the most accurate and precise stellar atmospheric parameters via spectroscopy. This is particularly important for determining the fundamental parameters of exoplanets, which directly depend on the stellar properties. However, different techniques can be implemented when analysing these spectra which will influence the results. These include performing an abundance analysis relative to the solar values in order to negate uncertainties in atomic data, and fixing the surface gravity (log g) to an external value such as those from asteroseismology. The choice of lines used will also influence the results. In this paper, we investigate differential analysis and fixing log g for a set of FGK stars that already have accurate fundamental parameters known from external methods. We find that a differential line list gives slightly more accurate parameters compared to a laboratory line list, however the laboratory line list still gives robust parameters. We also find that fixing the log g does not improve the spectroscopic parameters. We investigate the effects of line selection on the stellar parameters and find that the choice of lines used can have a significant effect on the parameters. In particular, removal of certain low excitation potential lines can change the Teff by up to 50 K. For future HoSTS papers we will use the differential line list with a solar microturbulence value of 1 km/s, and we will not fix the log g to an external value.