Modeling photometric variations due to a global inhomogeneity on an obliquely rotating star: Application to light curves of white dwarfs
Modeling photometric variations due to a global inhomogeneity on an obliquely rotating star: Application to light curves of white dwarfs
复制标题
对倾斜旋转恒星上的全局不均匀性引起的光度变化进行建模：在白矮星光变曲线中的应用
DOI：
10.1093/pasj/psac093
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发表时间：
2022
影响因子：
2.3
通讯作者：
Kashiyama Kazumi
中科院分区：
文献类型：
--
作者：
Suto Yasushi;Sasaki Shin;Aizawa Masataka;Fujisawa Kotaro;Kashiyama Kazumi
我们发展了一个计算具有轴对称非均匀表面的星星斜旋转引起的光度变化的一般框架。我们采用两种简单的表面不均匀性模型计算了白色矮星的光变曲线。根据表面模型和观测者的位置，所得到的光变曲线显示出与一小部分白色矮星所观察到的纯正弦曲线的偏离。作为一个具体的例子，我们将我们的模型拟合到观测到的快速旋转的白色矮星ZTF J190132.9+145808.7（旋转周期为419 s）的相位折叠光变曲线。我们发现，引起光度变化的光斑大小和角度分别为Δθs = 60°和θ s = 60°或90°，这意味着白色矮星表面磁场分布受到一个有趣的约束。
We develop a general framework to compute photometric variations induced by the oblique rotation of a star with an axisymmetric inhomogeneous surface. We apply the framework to compute light curves of white dwarfs adopting two simple models of their surface inhomogeneity. Depending on the surface model and the location of the observer, the resulting light curve exhibits a departure from a purely sinusoidal curve that is observed for a fraction of white dwarfs. As a specific example, we fit our model to the observed phase-folded light curve of a fast-spinning white dwarf ZTF J190132.9+145808.7 (with a rotation period of 419 s). We find that the size and obliquity angle of the spot responsible for the photometric variation are Δθs≈ 60° and θ⋆≈ 60° or 90°, respectively, implying an interesting constraint on the surface distribution of the magnetic field on white dwarfs.