Constraining the Evolutionary Pathways for White Dwarfs: Crystallization, Cooling Anomalies, and Mergers

限制白矮星的进化途径：结晶、冷却异常和合并

• 批准号: 2205736
• 负责人: Mukremin Kilic
• 金额: $ 36.86万
• 依托单位: University of Oklahoma Norman Campus
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-09-01 至 2025-08-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2205736&HistoricalAwards=false
• 关键词: Constraining; Evolutionary; Pathways; White; Dwarfs

White dwarfs (WD) are the final evolutionary state of stars like the sun: the star’s nuclear fuel is depleted and the core shrinks under its own gravity. A WD is very hot when it first forms but will gradually cool and crystallize over billions of years because it has no source of energy. WDs provide essential tools for understanding a variety of phenomena including type Ia supernovae and their use as cosmological distance indicators, single and binary star evolution, and the star formation history of the Galaxy. A team from the University of Oklahoma will focus on important questions pertaining to the physics of WD cooling and evolution. This project will achieve significant broader impact through two educational goals: 1- The Principal Investigator (PI) will continue his work at the University of Oklahoma Physics Department Lunar Sooner Outreach group, providing interactive demonstrations, lectures, question and answer panels, and stargazing events to scout groups and K-12 students, including the Cheyenne and Arapaho tribal students and 2- this project will provide research opportunities for graduate and undergraduate students, including members of under-represented groups.Using data from the Gaia satellite and the Sloan Digital Sky Survey (SDSS) the investigators will carry out a new spectroscopic survey of WDs in the SDSS footprint and within 100pc down to a temperature of 5000K. A previous survey by the same team obtained spectroscopy of white dwarfs hotter than 6000K: the extension to cooler temperatures is essential for resolving the current challenges in the cooling physics of WDs. The new survey will enable the team to obtain WD masses and luminosities for this cooler sample, including the so-called “ultracool” WDs. Comparing the luminosities and masses of the new cool sample to evolutionary models of WD cooling will allow the team to probe important physics such as crystallization, phase separation, and convective coupling for all WD masses for the first time. In addition, they will use wide WD binaries and “massive” WDs to test evolutionary models and WD merger rates. These are some of the most fundamental questions for our understanding of WD evolution.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.

白矮星（WD）是像太阳这样的恒星的最终进化状态：恒星的核燃料耗尽，核心在自身引力下收缩。WD刚形成时非常热，但由于没有能量来源，它会在数十亿年的时间里逐渐冷却并结晶。WDs为理解各种现象提供了必要的工具，包括Ia型超新星及其作为宇宙距离指示器、单星和双星演化以及银河系的恒星形成历史。来自俄克拉何马大学的一个团队将专注于与WD冷却和进化物理有关的重要问题。该项目将通过以下两个教育目标实现更广泛的重大影响：1-首席研究员（PI）将继续他在俄克拉何马大学物理系月球早期推广小组的工作，为童子军团体和K-12学生（包括夏延族和阿拉帕霍族学生）提供互动演示、讲座、问答小组和观星活动。2-该项目将为研究生和本科生（包括代表性不足的群体成员）提供研究机会。利用来自盖亚卫星和斯隆数字巡天（SDSS）的数据，研究人员将对SDSS足迹内的WDs进行新的光谱调查，并在100%内降低到5000K的温度。同一小组之前的一次调查获得了温度高于6000K的白矮星的光谱：将温度扩展到更低的温度对于解决当前WDs冷却物理中的挑战至关重要。新的调查将使团队能够获得这种较冷样品的WD质量和亮度，包括所谓的“超冷”WD。将新冷却样品的亮度和质量与WD冷却的进化模型进行比较，将使团队能够首次探测所有WD质量的重要物理特性，如结晶、相分离和对流耦合。此外，他们将使用宽WD二进制文件和“大规模”WD来测试进化模型和WD合并率。这些是我们理解WD进化的一些最基本的问题。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。

项目成果

The merger fraction of ultramassive white dwarfs

超大质量白矮星的合并部分

• DOI: 10.1093/mnras/stac3182
• 发表时间: 2022
• 期刊: Monthly Notices of the Royal Astronomical Society
• 影响因子: 4.8
• 作者: Kilic, Mukremin;Moss, Adam G.;Kosakowski, Alekzander;Bergeron, P.;Conly, Annamarie A.;Brown, Warren R.;Toonen, Silvia;Williams, Kurtis A.;Dufour, P.
• 通讯作者: Dufour, P.

General relativistic pulsations of ultra-massive ZZ Ceti stars

超大质量 ZZ 鲸鱼座恒星的广义相对论脉动

• DOI: 10.1093/mnras/stad2248
• 发表时间: 2023
• 期刊: Monthly Notices of the Royal Astronomical Society
• 影响因子: 4.8
• 作者: Córsico, Alejandro H.;Boston, S. Reece;Althaus, Leandro G.;Kilic, Mukremin;Kepler, S. O.;Camisassa, María E.;Torres, Santiago
• 通讯作者: Torres, Santiago

WD J004917.14−252556.81: the most massive pulsating white dwarf

WD J004917.14â252556.81：最大质量的脉动白矮星

• DOI: 10.1093/mnras/stad1113
• 发表时间: 2023
• 期刊: Monthly Notices of the Royal Astronomical Society
• 影响因子: 4.8
• 作者: Kilic, Mukremin;Córsico, Alejandro H.;Moss, Adam G.;Jewett, Gracyn;De Gerónimo, Francisco C.;Althaus, Leandro G.
• 通讯作者: Althaus, Leandro G.

The ubiquity of carbon dredge-up in hydrogen-deficient white dwarfs as revealed by GALEX

GALEX 揭示了缺氢白矮星中碳清除的普遍性

• DOI: 10.1093/mnrasl/slad105
• 发表时间: 2023
• 期刊: Monthly Notices of the Royal Astronomical Society: Letters
• 作者: Blouin, Simon;Kilic, Mukremin;Bédard, Antoine;Tremblay, Pier-Emmanuel
• 通讯作者: Tremblay, Pier-Emmanuel

The ELM Survey South. II. Two Dozen New Low-mass White Dwarf Binaries

• DOI: 10.3847/1538-4357/acd187
• 发表时间: 2023-05
• 期刊: The Astrophysical Journal
• 作者: A. Kosakowski;Warren R. Brown;M. Kilic;T. Kupfer;Antoine B'edard;A. Gianninas;M. Agueros;Manuel Barrientos