RUI: Collaborative Research: Characterizing Metal-Poor Stars in the APOGEE Survey

在过去的十年里，在阿帕奇角天文台（apachepoint Observatory）进行的一项调查收集了银河系中数千颗恒星的光谱。这个遗留数据集有很多用途。来自旧金山州立大学和加州大学圣克鲁兹分校的一个研究小组现在将利用这些数据寻找一种被称为“缺金属”的非常古老的恒星。这些非常小的恒星主要由氢和氦组成，几乎不包含更大的原子。它们很重要，因为它们形成于银河系——实际上是宇宙——非常年轻的时候。因此，这些恒星可以用来研究刚形成的银河系。该团队希望在远地点观测数据中发现300多颗来自全银河系的贫金属恒星。他们将使用利克和凯克望远镜重新观察这些恒星，以了解更多关于恒星本身和银河系历史的信息。收集到的数据将被旧金山州立大学和加州大学圣克鲁斯分校（一所为西班牙裔服务的机构）的学生使用。两个主要的外展项目，行星地球的天文学家和La Noche Plus，也将继续进行。前者教育公众关于气候变化的知识，而后者则把拉美裔高中的家庭带到利克天文台进行观察。还将开发新的教育视频。该项目将发现、分析并对阿帕奇角天文台银河演化实验（APOGEE）调查中观测到的300多颗缺金属候选恒星进行后续观测。该小组将通过在利克和凯克的后续观测来确定恒星参数和各种元素的丰度。缺乏金属的恒星的化学成分反映了核合成和星系聚集的最早阶段。近红外远地点观测数据使研究小组能够探测银河系中光学无法探测到的区域，比如凸起。描述银河系不同区域的贫金属恒星的数量和性质对于了解银河系的聚集历史是必不可少的。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

A survey being conducted at the Apache Point Observatory known as APOGEE has, over the last decade, collected thousands of spectra of stars in the Milky Way. This legacy data set is used for many purposes. A team from San Francisco State University and the University of California Santa-Cruz will now use the data to look for a type of very old star known as “metal poor”. These very small stars are mostly made of hydrogen and helium, and contain almost no larger atoms. They are important because they formed when the Milky Way – and indeed the universe – was very young. These stars can therefore be used to study our galaxy just after it was formed. The team expects to find over 300 metal-poor stars from all over the Milky Way in the APOGEE data. They will re-observe these stars using the Lick and Keck telescopes to learn more about the stars themselves and the history of the Milky Way. The data collected will be used by students from both San Francisco State University and the University of California at Santa Cruz, a Hispanic-Serving Institution. Two major outreach programs, Astronomers for Planet Earth and La Noche Plus, will also be pursued. The former educates the public on climate change, while the latter brings families from Latinx-dominated high schools to Lick Observatory for observing sessions. New educational videos will also be developed.The project will find, analyze, and conduct follow-up observations of over 300 metal-poor star candidates that have been observed in the Apache Point Observatory Galactic Evolution Experiment (APOGEE) survey. The team will determine stellar parameters and abundances of various elements using follow-up observations at Lick and Keck. The chemical compositions of metal-poor stars reflect the earliest stages of nucleosynthesis and galaxy assembly. The near-infrared APOGEE data allow the team to probe regions in the Milky Way that are not as accessible in the optical, such as the bulge. Characterizations of the numbers and properties of metal-poor stars in different regions of the galaxy are essential for understanding the assembly history of the Milky Way.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.