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

在过去的十年里，在阿帕奇点天文台进行的一项名为APOGEE的调查收集了银河系数千颗恒星的光谱。这一遗留数据集有多种用途。来自旧金山弗朗西斯科州立大学和加州大学圣克鲁斯分校的一个研究小组现在将利用这些数据来寻找一种被称为“贫金属”的非常古老的星星。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。它们之所以重要，是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我们的银河系刚刚形成时的情况。该团队预计将在APOGEE数据中找到来自银河系各地的300多颗贫金属恒星。他们将使用Lick和Keck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。收集的数据将由来自弗朗西斯科州立大学和加州大学圣克鲁斯分校（一所西班牙裔服务机构）的学生使用。两个主要的推广方案，行星地球天文学家和La Noche Plus，也将继续进行。前者教育公众了解气候变化，而后者则将拉丁裔占主导地位的高中的家庭带到利克天文台进行观测。该项目还将制作新的教育视频，对在阿帕奇点天文台银河演化实验（APOGEE）巡天中观测到的300多颗贫金属星星候选者进行寻找、分析和后续观测。该小组将利用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。贫金属恒星的化学成分反映了核合成和星系组装的最早阶段。近红外APOGEE数据使研究小组能够探测银河系中光学无法到达的区域，例如凸起。描述银河系不同区域贫金属恒星的数量和性质对于了解银河系的组装历史至关重要。该奖项反映了NSF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.