WoU-MMA: The White Dwarf Mass Distribution and the Gravitational Wave Foreground from Double White Dwarfs

WoU-MMA：白矮星质量分布和双白矮星的引力波前景

• 批准号: 1906379
• 负责人: Mukremin Kilic
• 金额: $ 39.96万
• 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: 2019
• 资助国家: 美国
• 起止时间: 2019-09-01 至 2023-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1906379&HistoricalAwards=false
• 关键词: WoU; MMA; White; Dwarf; Mass

White dwarf (WD) stars are extremely compact objects that are the remnants of stars of similar mass to the Sun, which have exhausted their nuclear fuel, but shine for billions of years from their residual heat. A research collaboration between the University of Oklahoma and the Smithsonian Astrophysical Observatory will study the population statistics of WDs, with an emphasis on extremely low-mass (ELM) double WDs, orbiting each other with periods as short as a few minutes. These studies are very important for astrophysics, since double or binary WDs are expected to be major sources of gravitational waves (GW) detected by future space-based GW observatories such as the planned LISA mission. They are also expected to eventually merge, leading to a stellar explosion or supernova (SN), of Type Ia, an important type of supernova that is used to measure the expansion rate of the universe. The investigators will use data from the Gaia space mission to identify candidate ELM WDs, and then use ground based telescopes to confirm the candidates and determine their characteristics. They will also study the entire population of WDs of all masses within about 300 light years of Earth. This project will provide research opportunities for graduate and undergraduate students, including members of under-represented groups. In conjunction with their research, the principal investigator and his students will provide interactive demonstrations, lectures, question and answer panels, and stargazing events to scout groups, middle and high school students, and K-12 students from Cheyenne-Arapaho and other tribes across Oklahoma, through the Lunar Sooners outreach group. Using parallaxes from the Gaia mission, ELM white dwarfs can be readily identified, since they are over-luminous compared to average mass WDs. These WDs are the signposts of ultra-compact binary systems with periods as short as 12 minutes. Finding such binaries is important for near-term population synthesis studies, for characterizing the expected GW foreground in the mHz frequency range from double WDs, and for significantly increasing the number of LISA verification sources. Well-measured WD binaries will be among the best Electromagnetic plus GW laboratories for understanding the formation of compact objects, dynamical interactions and tides in binaries, and energetic phenomena like Type Ia SNe. The Gaia 100 pc WD sample is essentially complete but contains an unexpected bifurcation in the color/absolute magnitude sequence that is mostly explained by the atmospheric composition. However, the distribution of hydrogen atmosphere WDs requires a population of massive (around 0.8-1 solar mass) WDs, which may be linked to merging WD binaries. This project will obtain an unbiased WD mass distribution and constrain the frequency of massive WDs. This project advances the goals of the NSF Windows on the Universe Big Idea.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）是极其致密的天体，是质量与太阳相似的恒星的残余物，这些恒星已经耗尽了核燃料，但仍因其余热而发光数十亿年。 俄克拉荷马大学和史密森天体物理观测站之间的一项研究合作将研究 WD 的总体统计数据，重点是极低质量 (ELM) 双 WD，它们彼此绕轨道运行的周期短至几分钟。 这些研究对于天体物理学非常重要，因为双或双星WD预计将成为未来天基引力波天文台（例如计划中的LISA任务）探测到的引力波（GW）的主要来源。 预计它们最终也会合并，导致 Ia 型恒星爆炸或超新星 (SN)，Ia 型超新星是一种重要的超新星类型，用于测量宇宙的膨胀率。 研究人员将使用盖亚太空任务的数据来识别候选 ELM WD，然后使用地面望远镜来确认候选者并确定其特征。 他们还将研究距地球约 300 光年范围内所有质量的 WD 的全部种群。 该项目将为研究生和本科生提供研究机会，包括代表性不足的群体的成员。 结合他们的研究，首席研究员和他的学生将通过 Lunar Sooners 外展小组，为来自夏安-阿拉帕霍和俄克拉荷马州其他部落的童子军团体、初中生和高中生以及 K-12 学生提供互动演示、讲座、问答小组和观星活动。利用盖亚任务的视差，可以很容易地识别 ELM 白矮星，因为与平均质量的 WD 相比，它们的亮度过高。这些 WD 是周期短至 12 分钟的超紧凑双星系统的路标。找到这样的双星对于近期群体综合研究、表征双 WD 在 mHz 频率范围内的预期引力波前景以及显着增加 LISA 验证源的数量非常重要。 精心测量的 WD 双星将成为最好的电磁加引力波实验室之一，用于了解致密天体的形成、双星中的动力相互作用和潮汐，以及 Ia 型超新星等高能现象。 Gaia 100 pc WD 样本基本上是完整的，但在颜色/绝对星等序列中包含意外的分歧，这主要是由大气成分解释的。然而，氢大气WD的分布需要大量（大约0.8-1个太阳质量）WD，这可能与WD双星的合并有关。该项目将获得无偏的 WD 质量分布并限制大量 WD 的频率。 该项目推进了 NSF 宇宙之窗大创意的目标。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力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

On the Nature of Ultracool White Dwarfs: Not so Cool after All

• DOI: 10.3847/1538-4357/ac76c7
• 发表时间: 2022-06
• 期刊: The Astrophysical Journal
• 作者: P. Bergeron;M. Kilic;S. Blouin;A. B'edard;S. Leggett;Warren R. Brown

Multiband light-curve analysis of the 40.5-min period eclipsing double-degenerate binary SDSS J082239.54+304857.19

• DOI: 10.1093/mnras/staa3571
• 发表时间: 2020-11
• 期刊: Monthly Notices of the Royal Astronomical Society
• 影响因子: 4.8
• 作者: A. Kosakowski;M. Kilic;Warren R. Brown

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

The ELM Survey. VIII. Ninety-eight Double White Dwarf Binaries

• DOI: 10.3847/1538-4357/ab63cd
• 发表时间: 2020-01
• 期刊: The Astrophysical Journal
• 作者: Warren R. Brown;M. Kilic;A. Kosakowski;J. Andrews;C. Heinke;M. Agueros;F. Camilo;A. Gianninas