Exploring the Impact of Substellar Objects on Late Stellar Evolution

最近，行星和棕矮星(介于行星和恒星之间的中等大小的物体)被发现在非常古老的恒星周围被发现，这些恒星已经喷出了大部分物质，留下了一颗被称为亚矮星B(SDB)的小热星。在抛射物质之前，SDB恒星是大型红巨星。因此，当这颗红巨星膨胀时，它们的行星和棕矮星一定已经被吞没了。PI计划使用小型望远镜来搜索更多的SDB恒星，并确定它们是否有伴星或棕矮星。他将确定恒星及其伴星的质量，并将新的数据集与恒星在寿命接近尾声时如何变化的理论进行比较。他将建立一个综合的研究和教育项目，首先教大学生用机器人望远镜观察。然后，学生们将教授高中教师和学生使用望远镜发现和分析SDB恒星。这将增强学生对STEM研究的兴趣和积极参与。在大量后公共信封SDB双星中找到伴星质量将为涉及红巨星吞没伴星相互作用的模型提供第一次稳健的测试。这项工作产生的质量下限将有助于约束与潮汐效应和角动量守恒有关的模型参数。轨道周期、偏心率和分量质量的确定将为热亚矮星的形成模型提供约束，并提高对恒星演化这一阶段的理解。PI通过与其他天文学家的合作，获得了EvryScope数据、天网和SOAR/Goodman望远镜。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Recently, planets and brown dwarfs (objects intermediate in size between planets and stars) have been discovered around very old stars that have ejected most of their material, leaving a small hot star known as a "subdwarf B" (sdB). Prior to ejecting material, the sdB stars were large red giant stars. Thus, their planets and brown dwarfs must have been engulfed as the red giant star expanded. The PI plans to use small telescopes to search for more of these sdB stars and determine whether they have companion planets or brown dwarfs. He will determine the masses of the stars and their companions, and compare the new data set with theories for how stars change near the end of their lifetimes. He will establish an integrated research and education program that will, first, teach university students to observe with robotic telescopes. The students will then teach high school teachers and students to use the telescopes to discover and analyze sdB stars. This will strengthen the students' interest and active participation in STEM research.Finding the companion masses in a large number of post-common envelope sdB binaries will provide the first robust tests of models involving red giant-engulfed companion interactions. The lower mass limits resulting from this work will help constrain model parameters relating to tidal effects and angular momentum conservation. Determination of orbital periods, eccentricities, and component masses will provide constraints on hot subdwarf formation models and improve understanding of this stage of stellar evolution. The PI, through collaborations with other astronomers, has access to Evryscope data, SKYNET, and the SOAR/Goodman telescopes.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.