AI 中文总结
该研究利用大双筒望远镜的PEPSI光谱仪，对32颗含褐矮星的FGK恒星进行光谱调查，在BACCHUS框架内用光谱合成法确定11种元素的恒星参数和丰度，分析相关比值差异及影响，评估钇镁恒星钟适用性，为JWST时代褐矮星观测提供支持。
AI 中文摘要
我们展示了对32颗拥有褐矮星的FGK恒星进行光谱调查的结果，使用了大双筒望远镜上的PEPSI光谱仪获得的高分辨率光学光谱（分辨率分别为130,000和50,000）。此次调查的主要目标是确定这些系统中11种元素（碳、氧、镁、硅、钙、铝、钛、铁、钇、硫和氮）精确的恒星参数和丰度。我们在BACCHUS框架内采用光谱合成来推导精确的恒星属性和元素丰度比。对于平均信噪比大于200的数据，有效温度的典型误差为42K，铁元素与氢元素丰度比的典型误差约为0.03 dex。我们观察到主要拥有宽轨道褐矮星的褐矮星宿主恒星样本中，碳氧比与太阳碳氧比存在显著差异。利用既定的理论化学框架，我们讨论了观测到的镁硅比和钙铝比对褐矮星伴星云层属性的影响。最后，我们评估了钇镁恒星钟对我们样本的适用性，并讨论了结果的更广泛意义。这项工作为宿主恒星提供了及时且统一的丰度分析，支持了詹姆斯·韦伯太空望远镜时代对褐矮星的扩展波长观测。
英文摘要
We present results from a spectroscopic survey of 32 FGK stars hosting brown dwarfs, using high-resolution optical spectra (R = 130,000 and 50,000) obtained with the PEPSI spectrograph on the Large Binocular Telescope. The primary goal of this survey is to determine precise stellar parameters and abundances for 11 elements (C, O, Mg, Si, Ca, Al, Ti, Fe, Y, S, and N) in these systems. We employ spectral synthesis within the BACCHUS framework to derive precise stellar properties and elemental abundance ratios. For our average S/N $>$ 200 data, we achieve a typical error of 42 K in T$_\mathrm{eff}$ and $\sim$0.03 dex for [Fe/H]. We observe a significant dispersion from a solar C/O ratio among the sample of brown dwarf host stars that host primarily wide-orbit brown dwarfs. Using established theoretical chemical frameworks, we discuss the implications of the observed Mg/Si and Ca/Al ratios for cloud properties in the brown dwarf companions. Finally, we evaluate the applicability of the [Y/Mg] stellar clock for our sample and discuss the broader implications of our results. This work provides a timely and uniform abundance analysis of host stars, supporting extended wavelength brown dwarf observations in the era of JWST.
CommentsAccepted to ApJ; fixed small typo in title
