Imaging Convective Patterns On AGB Stars

对 AGB 恒星上的对流模式进行成像

• 批准号: 1814777
• 负责人: Fabien Baron
• 金额: $ 25.1万
• 依托单位: Georgia State University Research Foundation, Inc.
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-09-15 至 2022-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1814777&HistoricalAwards=false
• 关键词: Imaging; Convective; Patterns; AGB; Stars

Even in the absence of distortions caused by our atmosphere, our ability to the resolve spatial structure of distant objects is limited by the diameter of telescope mirrors. Optical Interferometers, such as Georgia State University's Center for High Angular Resolution Astronomy (CHARA), get around this limitation by combining the signals received by smaller telescopes placed a long distance apart. We are now able to measure the sizes and shapes of bright stars, and we are beginning to be able to image their surfaces. This team will study the brightness variations on the surface of giant stars, which is caused by convection just beneath the surfaces. In turn, this will enable a better understanding of how the "winds" from these stars replenishes and enriches the interstellar medium, from which future generations of stars (and planets) are formed. This project will be used to train Georgia State University's undergraduate students in astronomy, optics, and computer science. The goal of this proposal is to image the surfaces of a group of chemically-diverse asymptotic giant branch (AGB) stars via long baseline near-IR interferometry using CHARA. The investigators will monitor the lifetime, size, and variability of the AGB convection patterns over the three-year duration of the project. Their maps of the surface effective temperatures will then be compared to predictions made by state-of-the-art 3D radiative-hydrodynamics models to determine regions of high mass-loss and to determine how that mass is distributed back into the interstellar medium via stellar winds. Imaging different types of AGBs with sub-milliarcsecond resolution will help quantify the roles of convection, pulsation, multiplicity and magnetism in the variability and mass-loss processes. The PI will also conduct workshops designed to help broaden the community of astronomers capable of obtaining and analyzing interferometric observations. They will also develop open source codes to produce images of a wide variety of stars from interferometric data.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.

即使在没有大气造成的扭曲的情况下，我们解决遥远物体的空间结构的能力也受到望远镜镜的直径的限制。 光学干涉仪，例如佐治亚州立大学的高角度分辨率天文学中心（CHARA），通过组合较小望远镜收到的信号，从而绕开了这一限制。 现在，我们能够测量明亮恒星的尺寸和形状，并且我们开始能够对其表面进行成像。 该团队将研究巨星表面的亮度变化，这是由对流在表面下方引起的。 反过来，这将使他们能够更好地了解这些恒星的“风”如何补充并丰富星际介质，从而形成后代的恒星（和行星）。该项目将用于培训佐治亚州立大学的本科生在天文学，光学和计算机科学方面。该提案的目的是通过使用CHARA的长基线近IIR干涉测量法对一组化学多样的渐近巨型分支（AGB）恒星进行成像。 调查人员将监视项目三年期间AGB对流模式的寿命，大小和变异性。 然后，它们的表面有效温度的地图将与最先进的3D辐射流动力学模型做出的预测进行比较，以确定高质量损失的区域，并确定如何通过恒星风将质量分布回星际介质。 用亚米利亚克秒分辨率对不同类型的AGB进行成像，将有助于量化对流，脉动，多样性和磁性在变异性和质量损失过程中的作用。 PI还将举办旨在扩大能够获得和分析干涉观察的天文学家社区的研讨会。 他们还将开发开源代码，以从干涉数据中产生各种恒星的图像。该奖项反映了NSF的法定任务，并使用基金会的知识分子优点和更广泛的影响审查标准，被认为值得通过评估来获得支持。

项目成果

A long-term study of the magnetic field and activity in the M giant RZ Ari: Magnetism and planet engulfment in a fairly evolved star?

对 M 巨星 RZ Ari 的磁场和活动的长期研究：相当演化的恒星中的磁性和行星吞噬？

• DOI: 10.1051/0004-6361/202346949
• 发表时间: 2024
• 期刊: Astronomy & Astrophysics
• 影响因子: 6.5
• 作者: Konstantinova-Antova, R.;Georgiev, S.;Lèbre, A.;Palacios, A.;Morin, J.;Bogdanovski, R.;Abbott, C.;Baron, F.;Aurière, M.;Drake, N. A.
• 通讯作者: Drake, N. A.

The Great Dimming of the Hypergiant Star RW Cephei: CHARA Array Images and Spectral Analysis

• DOI: 10.3847/1538-3881/ace59d
• 发表时间: 2023-07
• 期刊: The Astronomical Journal
• 作者: N. Anugu;F. Baron;D. Gies;C. Lanthermann;G. Schaefer;K. A. Shepard;T. Brummelaar;J. Monnier;S. Kraus;J. L. Bouquin;C. Davies;J. Ennis;T. Gardner;A. Labdon;R. Roettenbacher;B. Setterholm;W. Vollmann;C. Sigismondi

Long Term Evolution of Surface Features on the Red Supergiant AZ Cyg

• DOI: 10.3847/1538-4357/ac0c7e
• 发表时间: 2021-06
• 期刊: The Astrophysical Journal
• 作者: R. Norris;F. Baron;J. Monnier;C. Paladini;M. Anderson;A. O. Martinez;G. Schaefer;X. Che;A. Ch

Dynamical Surface Imaging of λ Andromedae

λ仙女座的动态表面成像

• DOI: 10.3847/1538-4357/ac06a5
• 发表时间: 2021
• 期刊: The Astrophysical Journal
• 作者: Martinez, Arturo O.;Baron, Fabien R.;Monnier, John D.;Roettenbacher, Rachael M.;Parks, J. Robert
• 通讯作者: Parks, J. Robert