Lifting the veil on Wolf-Rayet rotation using wind structure: Multi-wavelength and Spectropolarimetric Approaches

利用风结构揭开沃尔夫拉叶旋转的面纱：多波长和分光偏振方法

• 批准号: 2009412
• 负责人: Richard Ignace
• 金额: $ 30.28万
• 依托单位: East Tennessee State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-08-01 至 2024-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2009412&HistoricalAwards=false
• 关键词: Lifting; veil; Wolf; Rayet; rotation

When a Wolf-Rayet (WR) star goes supernova, its core collapses to form either a black hole or a neutron star. The outcome depends on how fast the WR star was spinning, but this is difficult to measure for WR stars, which are shrouded by their own wind. However, distortions in the wind can form corotating interaction regions (CIRs), which act as clocks and enable the spin period to be determined. Ignace and his team will monitor WR stars to look for CIRs. They will determine the spin period and further interpret these observations using their theoretical models to help us understand how wind features are formed. Undergraduate students will be recruited for a summer research program. Ignace and his team will develop a planetarium show for the general public and local high schools. The show on “space weather” will include a segment on how CIR’s in the Solar wind can enhance geomagnetic storms. The team will enhance an existing Monte Carlo radiative transfer code to characterize how rotational effects can modulate the wind and form CIRs. The comparison of the models to observations with the Echelle SpectroPolarimetric Device for the Observation of Stars on the Canada France Hawaii Telescope will result in a robust picture of the complex structures in WR winds. For the first time, the team will be able to relate electron scattering polarization in thick winds with a model for axisymmetric WR winds, as a function of stellar rotation relative to critical break-up. Modeling both varying and non-varying contributions to polarization is important for measuring periods and constraining mass-loss rates. To complete the picture, the team will model the influence of CIRs on variable IR/radio continuum flux. Polarization probes structures in the inner wind; the long-wavelength continuum probes the asymptotic flow.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.

当沃尔夫-拉叶（WR）星星变成超新星时，它的核心坍缩形成黑洞或中子星星。结果取决于WR星星旋转的速度，但这对于WR恒星来说很难测量，因为它们被自己的风所笼罩。然而，风的扭曲可以形成共转相互作用区（CIR），它起着时钟的作用，使自旋周期得以确定。伊尼亚斯和他的团队将监测WR星以寻找CIR。他们将确定旋转周期，并使用他们的理论模型进一步解释这些观测结果，以帮助我们了解风的特征是如何形成的。本科生将被招募参加夏季研究项目。伊尼亚斯和他的团队将为公众和当地高中开发一个天文馆表演。关于“太空天气”的节目将包括一个关于太阳风中的CIR如何增强地磁风暴的部分。该团队将增强现有的蒙特卡罗辐射传输代码，以表征旋转效应如何调制风并形成CIR。将模型与加拿大-法国夏威夷望远镜上用于观测恒星的埃歇尔分光偏振装置的观测结果进行比较，将得到WR风中复杂结构的可靠图像。这是第一次，该团队将能够将厚风中的电子散射极化与轴对称WR风模型联系起来，作为恒星旋转相对于临界分裂的函数。对偏振的变化和不变贡献进行建模对于测量周期和约束质量损失率是重要的。为了完成这幅图，该团队将模拟CIR对可变IR/无线电连续通量的影响。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值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

Radio Spectral Energy Distributions for Single Massive Star Winds with Free–Free and Synchrotron Emission

具有自由和同步加速器发射的单个大质量星风的无线电频谱能量分布

• DOI: 10.3847/1538-4357/ac6c90
• 发表时间: 2022
• 期刊: The Astrophysical Journal
• 作者: Erba, Christiana;Ignace, Richard
• 通讯作者: Ignace, Richard

Spectroscopic and evolutionary analyses of the binary system AzV 14 outline paths toward the WR stage at low metallicity

双星系统 AzV 14 的光谱和演化分析概述了低金属丰度下通往 WR 阶段的路径

• DOI: 10.1051/0004-6361/202345881
• 发表时间: 2023
• 期刊: Astronomy & Astrophysics
• 影响因子: 6.5
• 作者: Pauli, D.;Oskinova, L. M.;Hamann, W.-R.;Bowman, D. M.;Todt, H.;Shenar, T.;Sander, A. A.;Erba, C.;Gómez-González, V. M.;Kehrig, C.
• 通讯作者: Kehrig, C.

New Mass Estimates for Massive Binary Systems: A Probabilistic Approach Using Polarimetric Radiative Transfer

• DOI: 10.3847/1538-4357/ac589e
• 发表时间: 2022-02
• 期刊: The Astrophysical Journal
• 作者: A. Fullard;J. O’Brien;W. E. Kerzendorf;M. Shrestha;J. Hoffman;R. Ignace;Patrick van der Smagt

A scaling relationship for non-thermal radio emission from ordered magnetospheres: from the top of the main sequence to planets

• DOI: 10.1093/mnras/stab2168
• 发表时间: 2021-07
• 作者: P. Leto;C. Trigilio;J. Krtička;L. Fossati;R. Ignace;M. Shultz;C. Buemi;L. Cerrigone;G. Umana-G.