论文标题
分析具有旋转调制的八个磁性化学奇特恒星
Analysis of eight magnetic chemically peculiar stars with rotational modulation
论文作者
论文摘要
自2018年底以来，过境系外行星调查卫星（TESS）已为天文学群落提供了出色的光度法。我们已经使用苔丝数据研究了具有测得的大规模磁场（MCP恒星）的化学奇特恒星样品的光曲线中的旋转调制。通常，MCP恒星显示出大气中元素的不均匀分布，从而导致光谱（线轮廓）和光度法（光曲线）变化与旋转时期相称。我们在对其进行后处理后分析了50个扇区的八个扇区数据，以最大程度地减少系统的仪器趋势。对光曲线的分析使我们能够确定所有八个目标的旋转周期。对于每个恒星，我们提供了一个相图，该相图使用从光曲线和磁盘平均纵向磁场的可用测量值$ \ langle b _ {\ rm z} \ rangle $计算得出的相图。在大多数情况下，分阶段的光曲线和$ \ langle b _ {\ rm z} \ rangle $测量显示出一致的可变性。使用我们的旋转周期以及源自拟合的Balmer线配置文件的全局恒星参数，以及Geneva和Strömgren-Crawford光度法，我们确定了赤道旋转速度，并计算了相应的关键旋转旋转分数$ V _ {\ rm eq}/v _ {\ rm eq}/v _ {\ rm eq}/v _ {\ rm rm crit} $。我们从样本中表明，临界旋转分数随着恒星年龄的增长而减小，速度与较大的MCP恒星群中观察到的磁制动一致。
Since the end of 2018, the Transiting Exoplanet Survey Satellite (TESS) has provided stellar photometry to the astronomical community. We have used TESS data to study rotational modulation in the light curves of a sample of chemically peculiar stars with measured large-scale magnetic fields (mCP stars). In general, mCP stars show inhomogeneous distributions of elements in their atmospheres that lead to spectroscopic (line profile) and photometric (light curve) variations commensurate with the rotational period. We analyzed the available TESS data from 50 sectors for eight targets after post-processing them in order to minimize systematic instrumental trends. Analysis of the light curves allowed us to determine rotational periods for all eight of our targets. For each star, we provide a phase diagram calculated using the derived period from the light curves and from the available measurements of the disk-averaged longitudinal magnetic field $\langle B_{\rm z}\rangle$. In most cases, the phased light curve and $\langle B_{\rm z}\rangle$ measurements show consistent variability. Using our rotation periods, and global stellar parameters derived from fitting Balmer line profiles, and from Geneva and Strömgren-Crawford photometry, we determined the equatorial rotational velocities and calculated the respective critical rotational fractions $v_{\rm eq}/v_{\rm crit}$. We have shown from our sample that the critical rotational fraction decreases with stellar age, at a rate consistent with the magnetic braking observed in the larger population of mCP stars.
