AI 中文总结
研究HR 1614移动星团，通过对其成员星光谱测定化学丰度比，结合轨道频率分析，发现该星团是共振扰动盘特征，其恒星来自不同母星群，为移动星团起源研究提供新证据。
AI 中文摘要
移动星团是盘状恒星的集合，在速度和作用空间中聚集。对其起源有多种解释。本文研究对象是古老的HR 1614星团，过去已表明它不是解体星团。利用MIKE/麦哲伦望远镜对六颗成员星的高分辨率、高信噪比光谱，测定24种元素的化学丰度比。样本铁丰度在+0.13到+0.38 dex之间，多数丰度比与富金属银河系盘状恒星相符。除硫和钙外，各元素有显著丰度散射。等时线年龄显示星团年龄跨度大。轨道频率分析表明样本星落在共转薄共振上。结果支持HR 1614移动星团是共振扰动盘特征，聚集了内银河系不同母星群恒星的观点。
英文摘要
Moving groups (MGs) are ensembles of disk stars that clump in velocity and action space. A multitude of explanations as to their origin has been attempted, from dissolved star clusters to resonances with the Galactic bar, or other non-axisymmetric perturbations. The object of this work, the old HR 1614 group, has in the past already been shown to not be a disrupted cluster in terms of its broad age and metallicity distribution. Thus its stars have more likely been trapped by the Milky Way bar at corotation. Here, we present a new study that aims to chemically and dynamically characterize this group in the context of such a resonance. To this end, we used MIKE/Magellan high-resolution, high signal-to-noise spectra of six member stars of the HR 1614 MG to determine the chemical abundance ratios for 24 elements, several for the first time in those stars. The Fe-abundances of our sample range from +0.13 to +0.38 dex and the majority of abundance ratios is fully in line with those of metal-rich Milky Way disk stars, with few exceptions. In particular, the group's eponym, HR 1614, is enhanced in essentially all abundances and coincides with the higher-[X/Fe] trends of the Milky Way's thick disk. All elements (but S and Ca) show significant intrinsic abundance scatter that argue against this MG having formed in a contained environment such as a dissolved cluster. Isochrone ages, tailored to the measured metallicities support earlier findings of a broad age mix in this group, ranging from 1 Gyr to as old as 8 Gyr. We performed an orbital frequency analysis in a Galactic potential that includes a rotating bar. Indeed, our sample stars fall onto thin resonances on corotation. Hence, our results support the idea that the HR 1614 MG is a resonantly perturbed disk feature, mustering a melange of stars from different parent populations in the inner Galaxy.
Comments19 pages, 14 figures (incl. appendices); acccepted for publication in Astronomy & Astrophysics
