Heating of Dust Particles and Chondrule Formation Induced by Shock-Waves in Upper Layer of Protoplanetary Disks Generated by X-Ray Flares

研究了中心星星X射线耀斑产生的磁泡在中心星星周围原行星盘表面产生激波的现象。我们研究了冲击波的特性，以检查它们是否能加热盘中的尘埃颗粒，使其足以熔化，并根据冲击波加热模型形成球粒。特别是，我们着重讨论了以下三点：（1）这种现象是否可能发生，（2）如果发生，它们可能给盘中的物质带来什么样的影响，（3）我们是否可以通过天文和气象观测来知道这种现象的存在。为了解决这些问题，我们进行了磁流体动力学（MHD）数值模拟、辐射传输数值模拟和解析研究等工作，我们的MHD模拟揭示了与X射线耀斑相关的磁泡可以形成激波。其中一些冲击波 ...更多信息 不适合球粒的形成和尘埃颗粒的结晶。也就是说，（a）在距离中心恒星小于3 Au的圆盘区域中的尘埃颗粒可以被足够加热，（B）在距离中心恒星约5 Au的区域中的尘埃颗粒不太可能被冲击波加热，因为气泡由于准直而无法到达该区域。另一方面，由于详细的模拟，我们现在可以讨论尘埃颗粒被加热形成球粒和/或精确结晶的地方。我们可以讨论加热和结晶的尘埃颗粒可能被合并在彗星中的可能性。这一讨论意味着，由于激波加热只能发生在5 Au以内的区域，因此观测到的彗星中的结晶尘埃粒子应该是从太阳系内部区域转移过来的。少

We studied the phenomen that a magnetic bubble caused by X-Ray flare of the central star generates the shock waves at the surface of protoplanetary disks around the central star. And we looked at the characteristics of shock waves to examine if they can heat dust particles in the disk enough to melt them and form chondrules based on the shock-wave heating model for chondrule formation. Especially, we focused on following three points : (1) if such an phenomen may take place, (2) if it occurs what kind of effects they may bring to materials in the disk, and (3) if we can know the presence of the phenomen by making observation astronomically and meteoritically. To approach these problems, we have conducted Magneto-Hydrodynamics (MHD) numerical simulations, radiative transfer numerical simulations, analytic investigations, and so forth.Our MHD simulations have revealed that shock waves can be formed by the magnetic bubbles associated with X-Ray flares. And some of those shock waves turned … More out to be appropriate for chondrule formation and crystallization of dust particles. Namely, (a) dust particles in the disk region closer than 3 AU from the central star can be heated enough, and (b) it is unlikely that dust particle in a region further than about 5 AU are heated by the shock waves because the bubble would not reach that region due to the collimation.On the other hand, thanks to the detailed simulations, we can now discuss places where dust particles are heated to form chondrules and/or crystallize precisely. And we can discuss the possibility that heated and crystallized dust particles may be incorporated in comets. This discussion implies that crystallized dust particles in observed comets should be transferred from the inner region of the solar system, because the shock wave heating can only take place in a region closer than 5 AU.Some possible transfer mechanisms of dust particles have been proposed so far, but we need to investigate those mechanisms in detail in the future. Less