权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

The Gaia Satellite, White Dwarf Stars, and the Age of the Galaxy

盖亚卫星、白矮星和银河时代

基本信息

批准号：
1715718
负责人：
Ted von Hippel
金额：
$ 21.58万
依托单位：
Embry-Riddle Aeronautical University
依托单位国家：
美国
项目类别：
Continuing Grant
财政年份：
2017
资助国家：
美国
起止时间：
2017-07-01 至 2022-06-30
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1715718&HistoricalAwards=false
关键词：
Gaia Satellite White Dwarf Stars

项目摘要

The Milky Way is pictured as containing four major populations of stars known as the thin disk, thick disk, bulge, and halo. All these populations formed more than 8 billion years ago and must be younger than about 13.7 billion years old, the age of the Universe. For perspective, the Sun is about 4.5 billion years old. Yet, the ages of each of these Galactic populations is uncertain to one or two billion years. Without better knowledge of the ages of these populations, astronomers cannot answer fundamental questions about the formation of the Galaxy. To progress on these questions, astronomers need to improve how they determine the ages of stars. The investigators developed a new technique that more precisely determines the ages of stars than any prior technique. This technique takes advantage of data from the Gaia satellite and advanced Bayesian statistics.The project will train physics, mathematics, and software engineering students at Embry Riddle Aeronautical University in modern statistical and analysis methods. The students will gain valuable experience working with researchers and students abroad. The team includes the statistics group at Imperial College in London, England, and the Gaia research group at the Max Planck Institute in Heidelberg, Germany. The project is committed to including the full participation of women and underrepresented minorities. Therefore, the project will improve Science, Technology, Engineering, and Mathematics (STEM) education in the United States. It will also contribute to a diverse and globally competitive STEM workforce.Many types of stars are presently used as age proxies, yet among them white dwarf stars hold the most promise. A white dwarf's luminosity directly encodes its age, but this relies on accurately measuring its distance. The Gaia satellite is currently measuring the most accurate and precise trigonometric parallax distances ever obtained. Among the ~1.7 billion stars that Gaia is observing, there will be ~15,000 white dwarfs within 100 pc with typical distance uncertainties 1%. This compares to only two white dwarfs with distances presently known this accurately. The proposers will combine these Gaia data with optical and near-infrared photometry from ground-based surveys. They will analyze these data with their well-tested modeling technique, which relies on Bayesian statistics and state-of-the-art model ingredients. These unprecedented data and new modeling technique will allow the proposers to (1) derive ages for thousands of white dwarfs with typical age precisions of 1 to 5%, and then subsequently determine (2) the star formation history in the disk, (3) the onset and cessation of star formation in the thick disk, and (4) the mean age and age dispersion of the halo.

银河系被描绘成包含四个主要恒星群，分别是薄盘、厚盘、凸起和光晕。所有这些人口都形成于80亿多年前，一定比宇宙的年龄137亿年更早。从视角来看，太阳大约有45亿岁。然而，这些银河系人口中的每个人的年龄都不确定到一两亿年。如果不能更好地了解这些人群的年龄，天文学家就无法回答有关银河系形成的基本问题。为了在这些问题上取得进展，天文学家需要改进他们确定恒星年龄的方法。研究人员开发了一种新技术，比以前的任何技术都能更准确地确定恒星的年龄。这项技术利用了盖亚卫星的数据和高级贝叶斯统计学。该项目将对恩布里里德尔航空大学的物理、数学和软件工程专业的学生进行现代统计和分析方法的培训。这些学生将获得与国外研究人员和学生合作的宝贵经验。该团队包括英国伦敦帝国理工学院的统计小组和德国海德堡马克斯·普朗克研究所的盖亚研究小组。该项目致力于让妇女和代表性不足的少数群体充分参与。因此，该项目将改善美国的科学、技术、工程和数学(STEM)教育。它还将有助于建立一支多样化的、具有全球竞争力的STEM工作队伍。目前许多类型的恒星被用作年龄代替者，但其中白矮星最有希望。白矮星的光度直接决定了它的年龄，但这依赖于准确测量它的距离。盖亚卫星目前正在测量迄今获得的最精确和最精确的三角视差距离。在盖亚正在观测的大约17亿颗恒星中，将有大约15,000颗白矮星在100个pC内，典型的距离不确定度为1%。相比之下，目前只有两颗白矮星的距离是准确的。提出者将把这些Gaia数据与地面测量的光学和近红外测光技术结合起来。他们将使用经过良好测试的建模技术来分析这些数据，该技术依赖于贝叶斯统计和最先进的模型成分。这些史无前例的数据和新的模拟技术将使提出者能够(1)以1-5%的典型年龄精度获得数千颗白矮星的年龄，然后确定(2)盘中的恒星形成历史，(3)厚盘中恒星形成的开始和停止，以及(4)晕的平均年龄和年龄分散。

项目成果

期刊论文数量（11）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Precise Ages of Field Stars from White Dwarf Companions in Gaia DR2

DOI：
10.3847/1538-4365/abe468
发表时间：
2020-12
期刊：
The Astrophysical Journal Supplement Series
影响因子：
0
作者：
Dan Qiu;H. Tian;Xi-dong Wang;Jiachen Nie;T. Hippel;Gaochao Liu;M. Fouesneau;H. Rix
通讯作者：
Dan Qiu;H. Tian;Xi-dong Wang;Jiachen Nie;T. Hippel;Gaochao Liu;M. Fouesneau;H. Rix

Precise Ages of Field Stars from White Dwarf Companions

DOI：
10.3847/1538-4357/aaee74
发表时间：
2018-02
期刊：
The Astrophysical Journal
影响因子：
0
作者：
M. Fouesneau;H. Rix;T. von Hippel;D. Hogg;H. Tian
通讯作者：
M. Fouesneau;H. Rix;T. von Hippel;D. Hogg;H. Tian

A hierarchical model for the ages of Galactic halo white dwarfs

银晕白矮星年龄的分层模型

DOI：
10.1093/mnras/stx765
发表时间：
2017
期刊：
Monthly Notices of the Royal Astronomical Society
影响因子：
4.8
作者：
Si, Shijing;van Dyk, David A.;von Hippel, Ted;Robinson, Elliot;Webster, Aaron;Stenning, David
通讯作者：
Stenning, David

A Monte Carlo Method for Evaluating Empirical Gyrochronology Models and Its Application to Wide Binary Benchmarks

DOI：
10.3847/1538-4357/ac6035
发表时间：
2021-05
期刊：
The Astrophysical Journal
影响因子：
0
作者：
T. Otani;T. Hippel;D. Buzasi;T. Oswalt;Alexander Stone-Martinez;Patrice Majewski Embry-Riddle Aeronautical University-Patrice-Majewski-Embry-Riddl
通讯作者：
T. Otani;T. Hippel;D. Buzasi;T. Oswalt;Alexander Stone-Martinez;Patrice Majewski Embry-Riddle Aeronautical University-Patrice-Majewski-Embry-Riddl

Bayesian hierarchical modelling of initial–final mass relations acrossstar clusters