RUI: Understanding Close White Dwarf Binaries Using Planetary Nebula Central Stars

RUI：利用行星状星云中央恒星了解近距离白矮星双星

• 批准号: 2107768
• 负责人: Todd Hillwig
• 金额: $ 21.74万
• 依托单位: Valparaiso University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-09-01 至 2024-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2107768&HistoricalAwards=false
• 关键词: RUI; Understanding; Close; White; Dwarf

Between one third to one half of all stars are found in binary systems, and many in their late evolutionary stages will become close white dwarf (WD) binary stars, a short-lived stage consisting of either two closely spaced WDs or a WD-main sequence pair. These objects play an important role in many astrophysical contexts, including the “common envelope” (CE) phase in binary star evolution, non-spherical planetary nebulae (PNe) formation, cataclysmic variables (e.g., novae), as well as alternate pathways to type Ia supernovae (SNe), the latter serving as a key cosmological distance indicator. Insights into the formation and evolution of these systems depends on expanding the list of known examples, particularly those making up the central stars in planetary nebulae (CSPNe), which is the primary goal of a research program at Valparaiso University. This work will also support direct participation by undergraduate research students and further develop astronomy labs utilizing the Southeastern Association for Research in Astronomy (SARA) Observatory.Photometric and spectroscopic observing campaigns will be undertaken with the specific goal of doubling (from 90 to 160) the existing set of known close binary CSPNe. More detailed follow-up observations of the newly discovered binary CSPNe (as well as known examples) will be used with binary modeling to provide detailed system parameters such as each star’s mass, radius, and temperature. The newly increased set of known parameters will then be used to better understand the formation of double white dwarf (DWD) binaries and white dwarf binaries with a main sequence (MS) companion. The research team is working on Monte Carlo analysis and binary evolution calculations for DWD systems. That work will be expanded and updated as the observed sample size increases. The researchers will also use the results to test existing Monte Carlo, population evolution, and CE computations and the results will be available for other researchers to use as future constraints to their modeling. The results will also provide independent measures of DWD merger rates, SN Ia rates, and the SN Ia delay time distribution (DTD).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.

三分之一到二分之一的恒星存在于双星系统中，许多在演化后期将成为紧密的白矮星 (WD) 双星，这是一个短暂的阶段，由两个间隔很近的白矮星或一对白矮星主序对组成。这些天体在许多天体物理背景中发挥着重要作用，包括双星演化中的“共同包络”（CE）阶段、非球形行星状星云（PNe）形成、灾难性变量（例如新星）以及通往Ia型超新星（SNe）的替代途径，后者是关键的宇宙学距离指标。对这些系统形成和演化的深入了解取决于扩大已知例子的范围，特别是那些构成行星状星云（CSPNe）中心恒星的例子，这是瓦尔帕莱索大学研究项目的主要目标。这项工作还将支持本科生研究生的直接参与，并利用东南天文学研究协会 (SARA) 天文台进一步开发天文学实验室。将开展光度和光谱观测活动，其具体目标是将现有已知的近双星 CSPNe 数量增加一倍（从 90 到 160）。对新发现的双星 CSPNe（以及已知的例子）的更详细的后续观测将与双星建模一起使用，以提供详细的系统参数，例如每颗恒星的质量、半径和温度。新增加的一组已知参数将用于更好地了解双白矮星（DWD）双星和具有主序带（MS）伴星的白矮星双星的形成。研究团队正在致力于DWD系统的蒙特卡洛分析和二元演化计算。随着观察到的样本量的增加，这项工作将得到扩展和更新。研究人员还将使用这些结果来测试现有的蒙特卡罗、种群进化和 CE 计算，并且结果将可供其他研究人员用作未来建模的约束。结果还将提供 DWD 合并率、SN Ia 率和 SN Ia 延迟时间分布 (DTD) 的独立衡量标准。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力优点和更广泛的影响审查标准进行评估，被认为值得支持。