Monte Carlo Stellar Evolution Models and Isochrones

蒙特卡罗恒星演化模型和等时线

• 批准号: 2007174
• 负责人: Brian Chaboyer
• 金额: $ 38.35万
• 依托单位: Dartmouth College
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-09-01 至 2024-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2007174&HistoricalAwards=false
• 关键词: Monte; Carlo; Stellar; Evolution; Models

From determining the radius of exoplanet hosting stars, the ages of individual stars, to the age of distant protogalaxies, the use of stellar evolution models is ubiquitous in astrophysics. Stellar models require the use of a variety of physical parameters (such as nuclear reaction rates and opacities) and make a variety of assumptions (such as the nature of convection). The Principal Investigator and his students at Dartmouth College will use the best data available to test and improve stellar models. Their Monte Carlo approach will provide an estimate of the uncertainties associated with stellar modeling. The proposed research will form the core of student's PhD thesis. Through Dartmouth’s Women in Science Project, first year undergraduate women, jointly mentored by the PI and the graduate student, will be employed to assist in the project. The PI has developed an astronomy foreign studies program, which takes Dartmouth students to South Africa for an intensive 10-week introduction to astronomy and a rich introduction to South African culture, history, and scientific research.This project will test and improve stellar models by comparing the predicted colors and absolute magnitudes of the stellar models to relatively local stars which have accurate parallax distances obtained by the Gaia satellite in its most recent data release (DR3). It is important to have an understanding of the uncertainties associated with stellar models and isochrones. Instead of generating a single set of stellar models and isochrones which are based upon the best estimates for the various input parameters to stellar evolution models, a Monte Carlo approach will be used. For each physical stellar parameter (mass and chemical composition), a suite of a 1000 stellar evolution models will be generated by randomly sampling the uncertainties in the various input parameters (opacity, nuclear reaction rates, etc.) used to generate the models. This suite of stellar evolution models will be used to generate a suite of isochrones, and from these the user will be able to extract not just the best estimate for a given quantity (such as the radius, luminosity or age of a star), but also their associated 68% and 95% confidence limits. These uncertainty estimates can be incorporated into subsequent analysis by those who use the stellar models and isochrones to ensure that the uncertainty in derived quantities (such as age) reflect not just observational uncertainties, but also uncertainties associated with the theoretical models.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.

从确定系外行星恒星的半径，单个恒星的年龄，到遥远的原星系的年龄，恒星演化模型的使用在天体物理学中无处不在。恒星模型需要使用各种物理参数（如核反应速率和不透明度），并做出各种假设（如对流的性质）。首席研究员和他在达特茅斯学院的学生将使用最好的数据来测试和改进恒星模型。他们的蒙特卡罗方法将提供与恒星建模相关的不确定性的估计。这项研究将成为学生博士论文的核心。通过达特茅斯的妇女参与科学项目，由PI和研究生共同指导的一年级本科女生将被雇用来协助该项目。PI开发了一个天文学外国研究项目，该项目将达特茅斯的学生带到南非进行为期10周的天文学密集介绍，并对南非的文化，历史，该项目将通过将恒星模型的预测颜色和绝对星等与盖亚获得的具有精确视差距离的相对本地恒星进行比较，来测试和改进恒星模型卫星在其最新数据发布（DR3）。 理解与恒星模型和等时线有关的不确定性是很重要的。而不是产生一个单一的恒星模型和等时线，这是基于对恒星演化模型的各种输入参数的最佳估计，蒙特卡罗方法将被使用。对于每一个恒星物理参数（质量和化学成分），将通过对各种输入参数（不透明度、核反应速率等）的不确定性进行随机抽样，生成一套1000个恒星演化模型。用于生成模型。 这套恒星演化模型将用于生成一套等时线，用户将能够从中提取不仅是给定数量（如星星的半径，光度或年龄）的最佳估计，而且还可以提取其相关的68%和95%置信限。 这些不确定性估计可以被那些使用恒星模型和等时线的人纳入随后的分析中，以确保导出量的不确定性（如年龄）不仅反映了观测的不确定性，该奖项反映了NSF的法定使命，并被认为是值得通过使用基金会的智力价值和更广泛的影响审查进行评估来支持的的搜索.

项目成果

The Absolute Age of M92

M92的绝对年龄

• DOI: 10.3847/1538-3881/acd9b1
• 发表时间: 2023
• 期刊: The Astronomical Journal
• 作者: Ying, Jiaqi;Chaboyer, Brian;Boudreaux, Emily M.;Slaughter, Catherine;Boylan-Kolchin, Michael;Weisz, Daniel
• 通讯作者: Weisz, Daniel