具有超强磁场的富氦星CPD -62 2124的旋转调制变率和脉动
Rotationally modulated variability and pulsations of the He-rich star CPD -62 2124 with an extraordinarily strong magnetic field
摘要：
最近在CPD-62 2124中探测到一个强度为5.2kG的纵向磁场，其主序寿命分数约为60%。处于高级演化状态的强磁性早B型化学奇特星对于理解在全球磁场存在下角动量和自旋下降时间尺度的演化具有特殊意义。我们利用17 FORS 2低分辨率光谱偏振观测和844 ASAS 3光度测量的旋转周期，脉动，和磁场几何形状的恒星的测定。我们计算周期图和应用现象学模型的光度，光谱和spectropolarimetric的变化。我们发现，所有研究的量，特别是等效宽度，平均纵向磁场<B_z>，在V过滤器的通量，变化与同一周期P = 2.628 d，这被确定为旋转周期。观测到的变化完全可以用一颗刚性旋转的主序星来解释，这颗恒星的化学元素分布不均匀，光度计的斑点，以及一个稳定的，接近偶极的磁场，极场强度约为21 kG，冻结在恒星体内。CPD-62 2124的磁场相对于旋转轴倾斜β =28+-7度，而旋转轴朝向视线的倾斜度仅为i=20+-5度。在所获得的FORS 2光谱中，我们检测到短期的线轮廓变化，表明存在β造父神型脉动。到目前为止，还没有其他这种类型的脉动恒星拥有如此强大的磁场。
英文摘要：
A longitudinal magnetic field with a strength of 5.2kG was recently detected in CPD -62 2124, which has a fractional main-sequence lifetime of about 60%. Strongly magnetic early-B type chemically peculiar stars in an advanced evolutionary state are of special interest to understand the evolution of the angular momentum and spin-down timescales in the presence of a global magnetic field. We exploited 17 FORS2 low-resolution spectropolarimetric observations and 844 ASAS3 photometric measurements for the determination of the rotation period, pulsations, and the magnetic field geometry of the star. We calculated periodograms and applied phenomenological models of photometric, spectral and spectropolarimetric variability. We found that all quantities studied, specifically equivalent widths, the mean longitudinal magnetic field <B_z>, and the flux in the V filter, vary with the same period P = 2.628d, which was identified as the rotation period. The observed variations can be fully explained by a rigidly rotating main-sequence star with an uneven distribution of chemical elements, photometric spots, and a stable, nearly dipolar magnetic field with a polar field strength of about 21kG, frozen into the body of the star. The magnetic field of CPD -62 2124 is tilted to the rotation axis by beta=28+-7deg, while the inclination of the rotation axis towards the line of sight is only i=20+-5deg. In the acquired FORS2 spectra, we detect short-term line profile variations indicating the presence of beta Cephei type pulsations. As of today, no other pulsating star of this type is known to possess such a strong magnetic field.
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。
