AI 中文总结
研究富金属白矮星，通过对磁DZ白矮星WD1532+129进行光度、光谱等观测，发现其约289天的极长自转周期，可能源于角动量损失和缓慢旋转前身星，还揭示其表面金属分布及磁引导不均匀性是这类白矮星的共同特性。
AI 中文摘要
显示大气金属富集的白矮星为系外行星物质的整体组成提供了直接窗口，并对岩石系外行星系统的构成要素提供了一些最直接的限制。最近的研究表明，磁场可能会影响这种物质的吸积方式，可能会沿着磁力线引导碎片并将其保留在磁极附近，而不是使其在恒星表面均匀重新分布。我们报告了在磁DZ白矮星WD1532+129中发现的光度、光谱和偏振光谱变化，揭示了约289天的自转周期，这是迄今对任何简并恒星直接测量到的最长周期。观测到的周期可能是由导致白矮星阶段的演化过程中的角动量损失和一个异常缓慢旋转的前身星（可能是一颗磁Ap星）共同作用的结果。这颗白矮星表现出表面丰度不均匀，金属集中在两个磁极附近，观测到的调制与与磁几何结构对齐的局部富金属区域一致。WD1532+129是20秒差距内四个已知磁DZ白矮星中第三个显示出极区金属增强证据的，表明磁引导不均匀性是富金属磁白矮星的共同特性。
英文摘要
White dwarfs that show atmospheric metal enrichment offer a direct window into the bulk composition of exoplanetary material and provide some of the most direct constraints on the building blocks of rocky exoplanetary systems. Recent work has suggested that magnetic fields may influence how this material is accreted, potentially channelling debris along field lines and retaining it near magnetic poles rather than allowing it to be redistributed uniformly across the stellar surface. Here we report the discovery of photometric, spectroscopic, and spectropolarimetric variability in the magnetic DZ white dwarf WD1532+129, revealing a rotation period of about 289 days, by far the longest yet directly measured for any degenerate star. The observed period may result from the combined effect of angular-momentum loss during the evolution leading to the white dwarf stage and an unusually slowly rotating progenitor, perhaps a magnetic Ap star. The white dwarf exhibits surface abundance inhomogeneities, with metals concentrated near both magnetic poles, and the observed modulation is consistent with localised metal-rich regions aligned with the magnetic geometry. WD1532+129 is the third of the four known magnetic DZ white dwarfs within 20 pc to show evidence for polar metal enhancement, indicating that magnetically guided inhomogeneities are a common property of magnetic metal-enriched white dwarfs.
CommentsAccepted by A&A
