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文章简要叙述了有关大质量恒星形成的理论以及相关观测证据。目前大质量恒星形成的理论主要有两种,即吸积说和并合说.吸积说认为,大质量星可能与小质量星形成于相似的过程;并合说主张大质量星可能是由小质量年轻星碰撞合并而成.解决这两种理论争论的关键在于在大质量星附近能否观测到吸积盘的存在,最新的观测表明大质量星更有可能是通过吸积增加自身的质量,但最终解决这一问题可能还需要更多的观测证据。文章还提出了一些本领域尚未解决的问题,为感兴趣的研究者提供参考。 相似文献
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We study the non-thermal photon emission from shell-type supernova remnants (SNRs) in the frame of a two-zone model. In this model, the sites of acceleration, escape and subsequent radiation of particles (both electron and proton) are divided into acceleration and escape zones, respectively. The particle distributions consist of two components, one is produced inside the acceleration zone, the other in the escape zone. We apply this model to two young and one old shell-type SNRs and show that the observed multi-waveband photon spectra for the three SNRs can be explained well in this model and high-energy γ-rays from these SNRs may have hadronic origins. 相似文献
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The electron capture timescale may be shorter than hydrodynamic timescale in inner iron core of core-collapse supernova according to a recent new idea. Based on the new idea, this paper carries out a numerical simulation on supernova explosion for the progenitor model Ws15M. The numerical result shows that the size of proto-neutron star has a significant change (decrease about 20%), which may affects the propagation of the shock wave and the final explosion energy. 相似文献
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精细导星星库是空间大口径望远镜开展导星过程的必要组成部分,是用来确定空间望远镜视轴绝对指向的关键依据。基础星表的挑选、导星星库的容量、划分方式和天区搜索速度对于实现精细导星功能和性能指标都极为重要。在视场约为0.08 deg2精度要求高的条件下,选用UCAC4星表作为基础星表,提出混合分区星等过滤算法进行导星筛选,为了实现星表的快速搜索,对导星星表的存取方式进行了详细分析,构建了一个由约400万颗10 mv~16 mv导星组成的精细导星星库,并进行星库均匀性和搜索速度分析。仿真结果表明,基于UCAC4星表构建的16 mv精细导星星库全局均匀性达到0.44,导星搜索时间0.05 s,视场中星数适中,能被高效识别的概率达到75.51%,可作为精细导星星图识别的基准,支撑未来大口径空间望远镜的观测。 相似文献
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