Understanding Substellar Atmospheres: Constraining Physical Properties and Testing Models for Brown Dwarfs and Exoplanets

了解次恒星大气：约束褐矮星和系外行星的物理特性并测试模型

• 批准号: 2107516
• 负责人: Emily Rice
• 金额: $ 56.57万
• 依托单位: MACAULAY HONORS COLLEGE FOUNDATION
• 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: 2021-02-01 至 2022-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2107516&HistoricalAwards=false
• 关键词: Understanding; Substellar; Atmospheres; Constraining; Physical

The cool brown dwarf objects span the gap between stars with hotter temperatures and gas giant planets with much cooler temperatures. Scientists study these brown dwarf objects to understand how both planets and stars formed. The T dwarfs, a subset of the brown dwarfs, are the coolest well-populated group of these objects. Thus, they could be good analogs for the cool atmospheres of large exoplanets. However, we do not understand their atmospheric properties. The investigators will study those cooler substellar objects including T dwarfs and companions having planetary masses, and in-between transition objects. They will learn about the atmospheres, gravity, dust and cloud properties of these objects, and use this information to develop models to describe the properties of these substellar objects. This research serves the national interest by increasing our knowledge of these objects that are transitional between planets and stars, contributing to our understanding of planet formation. Undergraduate students from the CUNY colleges will work on this research. Public outreach events as different as the Astronomy on Tap program and Hayden Planetarium presentations will reach a diverse public audience.Brown dwarf objects, of which T dwarfs are the coolest well-populated spectral class, are promising analogs for the cool atmospheres of exoplanets, but the diversity of their atmospheric properties is not yet well understood. The principal investigators and team will conduct a comprehensive study of cool, substellar objects, including L-T transition objects, T dwarfs, Y dwarfs, and planetary-mass companions. The team will derive the physical and atmospheric properties; identify and calibrate spectral diagnostics of secondary parameters like gravity, metallicity, and dust/cloud properties of these substellar objects; and provide detailed feedback from model fits; thus establishing a foundation for exoplanet atmosphere studies. The team has the data and analysis tools in hand to curate benchmark objects, generate template spectra, and identify spectral outliers; create spectral energy distributions; calculate bolometric luminosities; fit synthetic spectra from atmospheric models to low, medium, and high resolution spectra; constrain age, radius, and mass using kinematics and evolutionary models; and curate a public compilation of benchmark and outlier objects. The principal investigators are experts in empirical analysis of brown dwarf spectra, photometric and kinematic analysis of brown dwarfs, and analysis with synthetic spectra from cool model atmospheres. Undergraduate students from the student population of the CUNY colleges will be incorporated in projects related to this research. Public outreach events such as the Astronomy on Tap program, STARtorial science fashion blog, Hayden Planetarium presentations, and the AstroBetter website, will reach and interact with a diverse public audience.

这些凉爽的棕矮星横跨在温度较高的恒星和温度较低的气态巨行星之间。科学家们研究这些褐矮星，以了解行星和恒星是如何形成的。T矮星是棕矮星的一个子集，是这些天体中最酷、人口最多的一组。因此，它们可以很好地类比大型系外行星的冷大气。然而，我们并不了解它们的大气性质。研究人员将研究那些较冷的星下天体，包括T矮星和具有行星质量的伴星，以及过渡天体之间的天体。他们将了解这些天体的大气、重力、尘埃和云层属性，并利用这些信息开发模型来描述这些恒星下天体的属性。这项研究通过增加我们对这些行星和恒星之间过渡天体的知识来服务于国家利益，有助于我们对行星形成的理解。纽约州立大学的本科生将参与这项研究。各种不同的公众推广活动，如Tap上的天文学计划和海登天文馆的演讲，都将接触到不同的公众。棕矮星是最酷的、人口最多的光谱类别，是系外行星凉爽大气的类似物，但它们的大气属性的多样性还没有被很好地理解。主要研究人员和团队将对冷的恒星下天体进行全面的研究，包括L-T过渡天体、T矮星、Y矮星和行星质量伴星。该团队将得出物理和大气特性；识别和校准这些恒星下天体的重力、金属丰度和尘埃/云特性等次级参数的光谱诊断；并从模型拟合中提供详细的反馈；从而为系外行星大气研究奠定基础。该团队手头有数据和分析工具，可以精选基准对象、生成模板光谱和识别光谱异常值；创建光谱能量分布；计算测辐射光度；将大气模型的合成光谱拟合到低、中、高分辨率光谱；使用运动学和进化模型约束年龄、半径和质量；以及编制基准和异常值天体的公开汇编。主要研究人员是棕矮星光谱的经验分析、棕矮星的光度和运动学分析以及凉爽模式大气合成光谱分析方面的专家。来自纽约州立大学学院的本科生将被纳入与这项研究相关的项目。公众推广活动，如天文学on Tap计划、STAR指南科学时尚博客、海登天文馆演示文稿和AstroBetter网站，将接触到不同的公众受众并与之互动。