慢脉动B型星KIC 8324482的星震学研究

Asteroseismic Analysis of the Slowly Pulsating B Star KIC 8324482

慢脉动B型(Slowly Pulsating B-type, SPB)星的脉动频率很难被地面观测设备所观测到,直到近些年空间观测技术的快速发展才使其得以实现. SPB星的研究尚处于起步阶段,恒星内部还存在许多问题等待解决.而星震学恰巧是一个用于探索恒星内部结构和相关的物理过程的有力工具.因此,星震学方法可以用来探测SPB星的内部结构和物理过程.通过用模型网格的方法对KIC 8324482这颗SPB星进行初步的星震学诊断,并通过计算其震荡数据(周期与周期间隔)的卡方值来筛选最佳拟合模型,确定了这颗星的一些基本物理参数,并发现了SPB星周期间隔的振荡频率和振幅与其对流核收缩留下的元素丰度梯度轮廓的关系.除了对流超射以外,扩散混合也是解释该恒星周期间隔分布结构的必要条件.

It is very difficult to resolve the oscillation frequencies of slowly pulsating B-type(SPB)stars by the ground-based observations.Therefore,the research of SPB stars is still at the early stage.And there are many questions of the stellar interiors.Asteroseismology is a powerful tool for probing stellar interiors and constraining the relative physical processes.Our goal is to probe the internal structure and physical process of SPB stars by using the method of astroseismology.In this paper,we make an asteroseismic analysis of the SPB star KIC 8324482 by calculating model grids.We select the best-fitting model by using the chi-squared method when doing model fittings in this work.Finally,we determine some fundamental parameters of this star.And our analytical result shows that KIC 8324482 must be a late-type SPB star with a central hydrogen mass fraction Xc=0:475?0:495.Besides,we find the frequency and amplitude of the oscillation pattern in the period spacings determined by the outline of the element abundances.In addition,the inclusion of diffusive mixing to core overshooting is essential to explain the structure in the observed period spacing pattern of this star.