论文标题
研究未进化的恒星Infra-Red Spectra的LTE离开
Study of the departures from LTE in the unevolved stars infra-red spectra
论文作者
论文摘要
我们提出了一项研究，研究了局部热力学平衡（LTE）在Na I，Mg I，Mg I，I，S I，K I，K I和SR II的红外线形成中，在光谱类型的未发展的恒星F，G，G，K和金属度周围是太阳金属周围的金属。这项研究的目的是识别这些物种的线条可以通过这些类型的恒星的红外光谱中的LTE近似安全处理。我们采用了一组40颗恒星，在3.5 m望远镜纳粹仪（TNG）上使用Giano光谱仪观察到，并先前由Caffau等人进行了研究。除SR II外，我们能够识别许多可以在所有上述物种中在LTE中处理的线。后一种物种只能使用J波段中的三条线进行研究，但所有这些物种都表现出与LTE的显着偏离。借助我们的小型但高质量的样本，我们可以以金属性来稳健地确定丰度比的趋势，从而从几个数量级的样本中证实了趋势，但在分辨率和S/N比方面质量较低。
We present a study of departures from Local Thermodynamic Equilibrium (LTE) in the formation of infra-red lines of Na I, Mg I, Al I, S I, K I and Sr II in unevolved stars of spectral types F,G,K and metallicities around the solar metallicity. The purpose of this investigation is to identify lines of these species that can be safely treated with the LTE approximation in the infra-red spectra of these types of stars. We employ a set of 40 stars observed with the GIANO spectrograph at the 3.5 m Telescopio Nazionale Galileo (TNG) and previously investigated by Caffau et al. We were able to identify many lines that can be treated in LTE for all the above-mentioned species, except for Sr II. The latter species can only be studied using three lines in the J-band, but all three of them display significant departures from LTE. With our small-size, but high-quality sample we can determine robustly the trends of the abundance ratios with metallicity, confirming the trends apparent from a sample that is larger by several orders of magnitude, but of lower quality in terms of resolution and S/N ratio.
