论文标题
振荡模式上的K2光度法可变性：新型脉动热B细分恒星EPIC 220422705
K2 photometry on oscillation mode variability: the new pulsating hot B subdwarf star EPIC 220422705
论文作者
论文摘要
我们介绍了热B细分史诗中振荡模式变异性的分析，这是一种从$ \ sim78 $〜天{\ em k} 2光度法中发现的新脉动器。高质量的光曲线可检测66个显着的独立频率，我们从中确定了9个不完整的电势三胞胎和3个五五联体。这些{\ sl g-}和{\ sl p-}的多重集分别在核心和表面上给出$ \ sim $ 36和29天的旋转周期，有可能暗示稍微差异的旋转。我们得出了分别为偶极子和四倍模式的序列的268.5 \，s和159.4 \，s的周期间距。我们表征了22个频率的幅度和频率调制（AM和FM）的精确模式，该频率具有足够高的幅度。其中许多表现出AM和FM的固有和周期性模式，并在最佳拟合和\ texttt {MCMC}测试中得出的几个月时间表。在排除其他机制后，非线性谐振模式相互作用可能是对此类AM和FMS的自然解释。我们的结果是从{\ em K} 2光度法和恒星振荡的非线性扰动理论之间构建桥梁的第一步。
We present an analysis of oscillation mode variability in the hot B subdwarf star EPIC~220422705, a new pulsator discovered from $\sim78$~days of {\em K}2 photometry. The high-quality light curves provide a detection of 66 significant independent frequencies, from which we identified 9 incomplete potential triplets and 3 quintuplets. Those {\sl g-} and {\sl p-}multiplets give rotation periods of $\sim$ 36 and 29 days in the core and at the surface, respectively, potentially suggesting a slightly differential rotation. We derived a period spacing of 268.5\,s and 159.4\,s for the sequence of dipole and quadruple modes, respectively. We characterized the precise patterns of amplitude and frequency modulations (AM and FM) of 22 frequencies with high enough amplitude for our science. Many of them exhibit intrinsic and periodic patterns of AM and FM, with periods on a timescale of months as derived by the best fitting and \texttt{MCMC} test. The nonlinear resonant mode interactions could be a natural interpretation for such AMs and FMs after other mechanisms are ruled out. Our results are the first step to build a bridge between mode variability from {\em K}2 photometry and nonlinear perturbation theory of stellar oscillation.
