K型相接双星次型现象的观测研究

Contact binaries are wonderful targets for the research of the interaction, as well as mass and energy transfer between component stars. One important character of them is that they have subclasses designated A-type and W-type, etc.. Samples with different subclasses show quite different statistical features, which implies that A- and W- types may have intrinsic and essential distinction. The study of these subclasses contributes to the foundation for the exploration of the major problem, such as the inner structure of contact binaries, and their formation and evolution. Contact binaries with K-type spectra are such a category. They have the latest spectra and smallest masses (contact binaries with M-type spectra need further confirmation). Their subclass distribution is very special that W-type is the dominant subclass in the known samples. This project focuses on the research of the intrinsic physical mechanism of this special subclass phenomenon, and the essential distinction between the different subclasses. The project is also to provide clues for some phenomena of contact binaries, such as the orbital period cut-off, and thus to solve some major problems of contact binaries. The applicant of this project has been doing the observation and research of K-type close binaries during his studying for PhD. Meanwhile, the team members are familiar with the data process and the analysis method related. The small and medium size telescopes of our country will guarantee our observation. All these conditions will facilitate the project and ensure the realization of the goal of science.

相接双星是研究子星相互作用及物质能量转移的极好对象，其重要的特征之一是存在A次型和W次型等不同次型的分类。不同次型样本的统计特征有明显的不同，反映出A次型和W次型可能具有内在和本质的区别，对次型的分析和研究是探索相接双星内部结构及其形成和演化等重大问题的基础。具有K型光谱型的相接双星是相接双星中光谱型最晚、子星质量最小的一类（光谱型为M型的还有待进一步确证）。它的次型分布比较特别，W次型在已发现的样本中占主导。本项目将研究这种特别的次型现象形成的内在物理机制以及不同次型的内在和本质的区别，为研究相接双星的周期截止等现象提供线索，为解决相接双星的一些重大问题提供依据。本项目的申请人博士阶段从事K型密近双星的观测和研究，同时项目组成员熟悉数据处理以及相关的一些分析研究方法，另外国内的中小口径望远镜为我们的观测提供了保障，这些因素为项目的顺利开展和实现科学目标提供了保证。

相接双星是密近双星中子星作用最密切的一类，是研究子星物质和能量交流的极好对象。晚型相接双星通常具有A和W两种次型，反映了相接双星系统不同的物理和结构信息。对次型的分析和研究有助于探索相接双星的内部结构及其形成和演化等重要问题。项目组成员根据文献调研选取的合适的K型样本目标，利用不同望远镜观测获取的测光和光谱资料，并对数据进行分析计算，获得了多个样本的物理参数和轨道参数。结果显示，与早期调查结果相仿，K型双星的实测样本均显示为W次型，即质量大的主星温度要比质量小的次型温度要低。这一不符合常规恒星物理理论的结果表明，K型相接双星的次型现象真实存在，反映了小质量子星的特殊性质，而不仅仅是主星高黑子覆盖的结果。相关结果正在撰写和投稿中。存在的问题是有部分文献报道发现有A次型的K星相接双星，原因可能要么是我们的样本选取不够全面，要么可能文献作者的参数计算不够准确。因此我们的结论需要进一步的确证。通过本课题的研究我们额外积累了不少样本的测光和光谱资料，对于后续相关课题的研究具有重要意义。我们在数据分析中编写积累了很多程序工具，对于将来的研究也大于裨益。