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arXiv 1707.09148astro-ph.SR
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SPB / $\mathbfβ$ Cep混合磁致伸缩器HD 43317的磁性表征

Magnetic characterization of the SPB/$\mathbfβ$ Cep hybrid pulsator HD 43317

B. Buysschaert, C. Neiner, M. Briquet, C. Aerts

摘要:

大质量恒星表面的大规模磁场不仅影响恒星的最外层,而且对内部深处也有影响,只有通过星震学才能观测到。我们进行了详细的描述的偶极磁场在B3.5V星HD 43317,SPB/ $β$ Cep混合闪烁器的表面,通过研究档案和新的Narval光谱偏振旋转调制磁场。此外,我们采用了基于网格的方法来比较塞曼签名与模型配置文件。通过研究由同向旋转表面丰度不均匀性引起的Narval和HARPS光谱中He线的旋转调制,我们将旋转周期更新为$0.897673\pm0.000004$ d。旋转轴和观测者视线之间的倾斜角仍然不明确,因为斯托克斯V的变化水平很低,恒星脉动模式导致强度分布变形。旋转轴和磁轴之间的夹角被限制为$β\in [67,90]^{\circ}$,偶极磁场的强度为1 kG到1.5kG的量级。恒星表面的这个磁场足够强,足以保证均匀旋转的辐射包络线,从而减少对流核心过冲,这在未来的正演地震建模中应该是可见的。

英文摘要:

Large-scale magnetic fields at the surface of massive stars do not only influence the outer-most layers of the star, but also have consequences for the deep interior, only observationally accessible through asteroseismology. We performed a detailed characterization of the dipolar magnetic field at the surface of the B3.5V star HD 43317, a SPB/$β$ Cep hybrid pulsator, by studying the rotationally modulated magnetic field of archival and new Narval spectropolarimetry. Additionally, we employed a grid-based approach to compare the Zeeman signatures with model profiles. By studying the rotational modulation of the He lines in both the Narval and HARPS spectroscopy caused by co-rotating surface abundance inhomogeneities, we updated the rotation period to $0.897673\pm0.000004$d. The inclination angle between the rotation axis and the observer's line of sight remains ill-defined, because of the low level of variability in Stokes V and deformations in the intensity profiles by stellar pulsation modes. The obliquity angle between the rotation and magnetic axes is constrained to $β\in [67,90]^{\circ}$, and the strength of the dipolar magnetic field is of the order of 1kG to 1.5kG. This magnetic field at the stellar surface is sufficiently strong to warrant a uniformly rotating radiative envelope, causing less convective core overshooting, which should be visible in future forward seismic modeling.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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