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: 1614527
• 负责人: Emily Rice
• 金额: $ 56.57万
• 依托单位: CUNY College of Staten Island
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-09-01 至 2021-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1614527&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.

冷的褐矮星跨越了温度更高的恒星和温度低得多的气体巨行星之间的差距。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型矮星是褐矮星的一个子集，是这些天体中最冷、人口最多的一组。因此，它们可能是大型系外行星冷大气的良好类似物。然而，我们并不了解它们的大气特性。研究人员将研究那些较冷的亚恒星物体，包括T矮星和具有行星质量的同伴，以及介于两者之间的过渡物体。他们将了解这些物体的大气、重力、尘埃和云的特性，并利用这些信息开发模型来描述这些亚恒星物体的特性。这项研究通过增加我们对行星和恒星之间过渡的这些物体的知识，有助于我们对行星形成的理解，从而为国家利益服务。来自纽约市立大学的本科生将从事这项研究。公共宣传活动，如Astronomy on Tap计划和Hayden Planetarium演示，将接触到不同的公众观众。褐矮星天体，其中T型矮星是最冷的人口稠密的光谱类别，是有希望的类似物的冷大气的系外行星，但其大气性质的多样性还没有得到很好的理解。主要研究人员和团队将对冷的亚恒星物体进行全面研究，包括L-T过渡物体，T矮星，Y矮星和行星质量的同伴。该团队将获得物理和大气特性;识别和校准次级参数的光谱诊断，如重力，金属丰度和这些亚恒星物体的尘埃/云特性;并提供来自模型拟合的详细反馈;从而为系外行星大气研究奠定基础。该团队拥有数据和分析工具来管理基准对象，生成模板光谱，并识别光谱异常值;创建光谱能量分布;计算辐射热光度;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;并管理基准和异常对象的公共汇编。主要研究人员是褐矮星光谱的经验分析，褐矮星的光度和运动学分析以及冷模型大气合成光谱分析的专家。来自纽约市立大学各学院的本科生将参加与这项研究有关的项目。公共宣传活动，如天文学自来水计划，STARtorial科学时尚博客，海登天文馆介绍，和AstroBetter网站，将达到和互动与不同的公众观众。