论文标题
由于脉冲驱动的冲击,齿状射击的相位调节X射线排放
Phase-modulated X-ray Emission from Cepheids due to Pulsation-Driven Shocks
论文作者
论文摘要
头孢虫是脉动变量恒星,在接近其最小半径相的UV波长下具有周期性色球响应。最近,在\ emph {maximum}半径阶段的观测值中捕获了X射线变量签名。这种X射线排放令人惊讶,尚不理解。在这项工作中,我们使用现代天体物理代码冥王星来研究脉动对头孢虫X射线发射的影响。我们运行许多具有多种初始和边界条件的流体动力数值模拟,以探索冲击能力产生观察到的相位依赖性X射线行为的能力。最后,我们使用X射线源(SOXS)软件包的模拟观测值来为每个模拟情况创建合成光谱,并将我们的模拟与可观察结果联系起来。我们表明,在某些条件下,我们可以在头孢虫处最大半径时在0.4--0.8阶段重现观察到的X射线通量。 Our results span a wide range of mass-loss rates, $2\times10^{-13}$--$3\times10^{-8}$ $M_\odot$ yr$^{-1}$, and peak X-ray luminosities, $5\times10^{-17}$--$1.4\times10^{-12}$ erg cm$^{-2}$ s $^{ - 1} $。我们得出的结论是,cepheids表现出\ textit {两个组件发射},(a)电击波负责相关变量发射(0.2-0.6),并且(b)单独的静态机制是其余阶段的主要发射机制。
Cepheids are pulsating variable stars with a periodic chromospheric response at UV wavelengths close to their minimum radius phase. Recently, an X-ray variable signature was captured in observations during the \emph{maximum} radius phase. This X-ray emission came as a surprise and is not understood. In this work, we use the modern astrophysical code, PLUTO, to investigate the effects of pulsations on Cepheid X-ray emission. We run a number of hydrodynamic numerical simulations with a variety of initial and boundary conditions in order to explore the capability of shocks to produce the observed phase-dependent X-ray behavior. Finally we use the Simulated Observations of X-ray Sources (SOXS) package to create synthetic spectra for each simulation case and link our simulations to observables. We show that, for certain conditions, we can reproduce observed X-ray fluxes at phases 0.4--0.8 when the Cepheid is at maximum radius. Our results span a wide range of mass-loss rates, $2\times10^{-13}$--$3\times10^{-8}$ $M_\odot$ yr$^{-1}$, and peak X-ray luminosities, $5\times10^{-17}$--$1.4\times10^{-12}$ erg cm$^{-2}$ s$^{-1}$. We conclude that Cepheids exhibit \textit{two component emission} with (a) shock waves being responsible for the phase dependent variable emission (phases 0.2 - 0.6), and (b) a separate quiescent mechanism being the dominant emission mechanism for the remaining phases.