Radio Studies of Planetary Nebulae: Probing Radiation-driven Molecular Chemistry

行星状星云的射电研究：探测辐射驱动的分子化学

• 批准号: 2206033
• 负责人: Joel Kastner
• 金额: $ 33.94万
• 依托单位: Rochester Institute of Tech
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-08-15 至 2025-07-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2206033&HistoricalAwards=false
• 关键词: Radio; Studies; Planetary; Nebulae; Probing

Stars generate their energy through fusion of hydrogen to helium in their cores. When a star's hydrogen supply runs out, the star expands dramatically to become a "red giant". Red giants generate elements (like carbon and oxygen) that are essential for life as we know it. The outer layers of a red giant, which are only weakly bound to the star's core by gravity, are easily driven away from the star by its intense radiation. Intense ultraviolet radiation from the star's hot core then can turn the ejected red giant gas into a giant, glowing plasma cloud that astronomers call a "planetary nebula". Some planetary nebulae also contain a rich mixture of chemicals, in molecular form, that may resemble the atmosphere of the young Earth. Each planetary nebula thereby gives us a snapshot of the process by which stars enrich the Universe in the building blocks of life. The investigator will use radio telescope observations of planetary nebulae to determine the mixture of molecular gases that are released into interstellar space. The results will advance the field of astronomy by deepening human understanding of how the essential elements of life arrived on Earth and might arrive on planets orbiting other stars. To support education and diversity in the sciences, the investigator will also develop a summer short course for middle and high school students to explain, among other things, how astronomers determine the compositions of interstellar gases, and will generate exhibits about planetary nebulae for use in planetariums around the world.The extremes of physical conditions within molecule-rich planetary nebulae make these geometrically simple objects particularly fertile ground for research. Images of these regions aid in improving astronomers' understanding of radiation-driven chemistry in (UV) photon-dominated regions (PDRs) and X-ray-dominated regions (XDRs). The investigator plans a comprehensive campaign of observations and modeling of key tracers of irradiated molecular gas for a sample comprising the nearest and best-studied molecule-rich planetary nebulae (PNe). The investigator will fully exploit the broad frequency coverage and wide-field mapping capabilities of single-dish and interferometric (sub)mm-wave radio astronomy facilities, including the Atacama Large Millimeter Array (ALMA). The investigator will make use of "off-the-shelf" modeling codes to interpret the observational results in terms of molecular gas distributions, temperatures, densities, and compositions within the target PNe. The results will have broad applicability, given that the PDRs and XDRs in the PNe, that are the focus of this study, are representative of a diverse array of astrophysical environments, from star-forming cores within molecular clouds to molecular tori surrounding active galactic nuclei.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.

恒星通过将核心中的氢聚变为氦来产生能量。当一颗恒星的氢气供应耗尽时，这颗恒星就会戏剧性地膨胀，成为一颗“红巨星”。红巨星产生我们所知的生命所必需的元素(如碳和氧)。红巨星的外层在引力的作用下只与恒星的核心有微弱的结合，很容易被恒星的强烈辐射驱离。来自恒星热核的强烈紫外线辐射可以将喷出的红色巨型气体转变为巨大的、发光的等离子云，天文学家将其称为“行星星云”。一些行星状星云还含有丰富的分子形式的化学混合物，可能类似于年轻地球的大气。因此，每个行星状星云都为我们提供了恒星丰富宇宙生命的过程的快照。研究人员将使用射电望远镜对行星星云的观测来确定释放到星际空间的分子气体的混合物。这一结果将通过加深人类对生命要素如何到达地球以及可能到达绕其他恒星运行的行星的理解，从而推动天文学领域的发展。为了支持科学教育和多样性，研究人员还将为初中生和高中生开发一个暑期短期课程，解释天文学家如何确定星际气体的组成，并将制作关于行星星云的展品，供世界各地的天文馆使用。富含分子的行星星云内极端的物理条件使这些几何形状简单的物体特别适合研究。这些区域的图像有助于提高天文学家对(UV)光子主导区域(PDR)和X射线主导区域(XDR)中辐射驱动的化学的理解。研究人员计划对辐射分子气体的关键示踪物进行全面的观测和建模，以获得最近和研究最充分的富含分子的行星星云(PNE)。调查员将充分利用单盘和干涉(亚)毫米波射电天文设施的宽频率覆盖和宽视场测绘能力，包括阿塔卡马大毫米阵列(ALMA)。研究人员将利用“现成”的建模代码，根据目标PNE内的分子气体分布、温度、密度和组成来解释观测结果。这些结果将具有广泛的适用性，因为PNE中的PDR和XDR是本研究的重点，代表了一系列不同的天体物理环境，从分子云中的恒星形成核心到活动星系核周围的分子环。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

Mapping NGC 7027 in New Light: CO + and HCO + Emission Reveal Its Photon- and X-Ray-dominated Regions

以新视角绘制 NGC 7027：CO 和 HCO 发射揭示其光子和 X 射线主导区域

• DOI: 10.3847/1538-4357/aca405
• 发表时间: 2022
• 期刊: The Astrophysical Journal
• 作者: Bublitz, Jesse;Kastner, Joel H.;Hily-Blant, Pierre;Forveille, Thierry;Santander-García, Miguel;Alcolea, Javier;Bujarrabal, Valentin;Wilner, David J.;Montez, Jr., Rodolfo;Aleman, Isabel
• 通讯作者: Aleman, Isabel

The messy death of a multiple star system and the resulting planetary nebula as observed by JWST

• DOI: 10.1038/s41550-022-01845-2
• 发表时间: 2022-12
• 期刊: Nature Astronomy
• 影响因子: 14.1
• 作者: O. De Marco;Muhammad Akashi;S. Akras;J. Alcolea;I. Aleman;P. Amram;B. Balick;E. De Beck;E. Blackman;H. Boffin;P. Boumis;J. Bublitz;B. Bucciarelli;V. Bujarrabal;J. Cami;N. Chornay;Y. Chu;R. Corradi;A. Frank;D. A. García-Hernández;J. García-Rojas;G. García-Segura;V. Gómez-Llanos;D. Gonçalves;M. Guerrero;David Jones;A. Karakas;J. Kastner;S. Kwok;F. Lykou;A. Manchado;M. Matsuura;I. McDonald;B. Miszalski;S. Mohamed;A. Monreal-Ibero;H. Monteiro;R. Montez;P. Baez;C. Morisset;J. Nordhaus;C. L. Mendes de Oliveira;Z. Osborn;M. Otsuka;Q. Parker;E. Peeters;B. Quint;G. Quintana-Lacaci;M. Redman;A. Ruiter;L. Sabin;R. Sahai;C. Contreras;M. Santander-García;I. Seitenzahl;N. Soker;A. Speck;L. Stanghellini;W. Steffen;J. Toalá;T. Ueta;G. C. Van de Steene;H. Van Winckel;P. Ventura;E. Villaver;W. Vlemmings;J. Walsh;R. Wesson;A. Zijlstra