Demographics of the Youngest Protostars and their Disks

最年轻的原恒星及其圆盘的人口统计

• 批准号: 2001830
• 负责人: Patrick Sheehan
• 金额: $ 30万
• 依托单位: Sheehan Patrick D
• 依托单位国家: 美国
• 项目类别: Fellowship Award
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-07-01 至 2022-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2001830&HistoricalAwards=false
• 关键词: Demographics; Youngest; Protostars; their; Disks

Patrick Sheehan is awarded an NSF Astronomy and Astrophysics Postdoctoral Fellowship to conduct a program of research and education at Northwestern University. He will study the structures and properties of disks, which are formed when clouds of gas and dust in space collapse to form protostars. Observational evidence suggests that planets and their precursors are formed very early during the onset of star formation, and the results from this project will allow astronomers to understand just how soon planet formation begins. Along with this research, Sheehan will conduct a summer educational program designed to provide experience in programming, data analysis, and astronomical research to high school students.Recent observations of substructures in protoplanetary disks surrounding nearly every 1-5 Myr-old pre-main sequence star suggest that these disks may already have undergone a significant amount of planet or planetesimal formation. To understand the initial conditions before significant dust processing or planet formation has occurred, this project will investigate the structures of younger disks ( 1 Myr old) and their central protostars using observations done at very high angular resolution from centimeter to submillimeter wavelengths. The observations will include every known protostellar disk in the Taurus star-forming region, enabling Sheehan to place constraints on the structure of gas and dust and on the growth of early dust grains. Sheehan will also use high-resolution imaging to study a known population of young disks in the Orion star-forming region with substructures possibly related to early planet formation. Finally, he will directly measure the dynamical masses of young protostars to place these disks within the context of their stars and place robust constraints on pre-main sequence evolutionary tracks. This project will generate the largest sample of directly measured protostellar masses, and the measurements will provide information on how disk mass depends on protostellar mass. The resulting comprehensive picture will advance our understanding of the potential for planet formation in disks, as well as the precise location of the forming planets.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.

帕特里克希恩被授予NSF天文学和天体物理学博士后奖学金，在西北大学进行研究和教育计划。 他将研究圆盘的结构和性质，圆盘是当太空中的气体和尘埃云坍缩形成原恒星时形成的。 观测证据表明，行星及其前身在星星形成的初期就形成了，这个项目的结果将使天文学家了解行星形成的开始时间。 沿着这项研究，希恩将进行一个暑期教育计划，旨在提供编程，数据分析和天文学研究的经验，以高中学生。最近的观察，在原行星盘的子结构周围几乎每一个1-5万年前的主序星星表明，这些磁盘可能已经经历了大量的行星或星子的形成。为了了解在重要的尘埃加工或行星形成之前的初始条件，该项目将使用从厘米到亚毫米波长的非常高的角分辨率进行的观测来研究较年轻的盘（100万年）及其中心原恒星的结构。这些观测将包括金牛座恒星形成区的每一个已知的原恒星盘，使希恩能够对气体和尘埃的结构以及早期尘埃颗粒的生长进行限制。Sheehan还将使用高分辨率成像来研究猎户座恒星形成区域中已知的年轻圆盘群，其子结构可能与早期行星形成有关。最后，他将直接测量年轻原恒星的动力学质量，将这些圆盘置于恒星的背景下，并对主序前演化轨道进行严格的限制。 该项目将产生直接测量的原恒星质量的最大样本，测量结果将提供关于盘质量如何取决于原恒星质量的信息。由此产生的全面的图片将促进我们对行星盘形成的潜力的理解，以及形成行星的精确位置。这个奖项反映了NSF的法定使命，并已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标准进行评估的支持。

项目成果

The VLA/ALMA Nascent Disk and Multiplicity (VANDAM) Survey of Orion Protostars. III. Substructures in Protostellar Disks

• DOI: 10.3847/1538-4357/abbad5
• 发表时间: 2020-10
• 期刊: The Astrophysical Journal
• 作者: P. Sheehan;J. Tobin;S. Federman;S. Megeath;L. Looney

The VLA/ALMA Nascent Disk and Multiplicity (VANDAM) Survey of Orion Protostars. VI. Insights from Radiative Transfer Modeling

• DOI: 10.3847/1538-4357/ac574d
• 发表时间: 2022-02
• 期刊: The Astrophysical Journal
• 作者: P. Sheehan;J. Tobin;L. Looney;S. Megeath

A VLA View of the Flared, Asymmetric Disk around the Class 0 Protostar L1527 IRS

• DOI: 10.3847/1538-4357/ac7a3b
• 发表时间: 2022-06
• 期刊: The Astrophysical Journal
• 作者: P. Sheehan;J. Tobin;Zhi-Yun Li;M. V. ’. van ’t Hoff;J. Jørgensen;W. Kwon;L. Looney;N. Ohashi;S. Takakuwa;Jonathan P. Williams;Yusuke Aso;S. Gavino;I. Gregorio-Monsalvo;I. Han;C. Lee;A. Plunkett;Rajeeb Sharma;Y. Aikawa;S. Lai;Jeong-Eun Lee;Zheyu Lin;K. Saigo;K. Tomida;Hsi-Wei Yen