恒星和恒星系统的星震学研究

For recent years, great progress in observation has led to detection of stellar oscillations for the stars over the whole H-R diagram. Study of stellar oscillation with both observation and theoretical research — asteroseismology — provides unique opportunity and robust tool to detect and study the internal structure of stars. We plan to make systematic time-series photometric and spectroscopic observations for a number of selected pulsating single stars and variable stars in open clusters with the major observational facilities of China including the two 2-meter class telescopes as well as several international observation networks. Combined with the data already obtained including the released data of the LAMOST survey and the data collected with CSTAR from Antarctica, we shall search for new variable stars, study the oscillation property of the target stars, select target stars for the SONG-China project. We shall also construct a series of numerical models with theoretical modeling codes, determine the best-fitted models by comparing the theoretically-calculated frequencies and the observationally-detected frequencies. Hence the stellar parameters of the target stars can be measured precisely and the internal structure of the stars will be detected. Furthermore, the physics process including overshooting and diffusion of elements inside the stars would be better constrained. Asteroseismology of multiple types of stars and stellar systems would help improving our knowledge on stellar internal structure and evolutionary law. This is also important scientifically in understanding the structures and evolutionary laws of the Galaxy and even extra-galaxies.

近年来观测方面的巨大进展导致在全赫罗图范围发现恒星振动现象。针对恒星振动的观测结合理论的研究—星震学—提供了探测和研究恒星内部结构的唯一机会和有力手段。本项目计划对一批脉动单星和疏散星团中脉动变星，依托两台2米级望远镜等国内主力天文观测设备，结合国际联测网，进行系统的时序测光和光谱观测，并利用LAMOST先导巡天发布的光谱数据和中国南极小望远镜时序测光数据等已有的观测资料，搜寻新的脉动变星，深入研究恒星振动性质，并为SONG项目中国计划的选源进行准备；利用已有程序构建目标星的理论模型，通过对照理论模型的本征振动频率和观测得到的振动频率，确定最佳模型，得出目标星的基本参数，研究恒星内部物理结构，进而研究恒星内部物质扩散和对流超射等物理过程。对一批不同类型恒星和恒星系统的星震学研究，将有利于增进对多类恒星内部结构和演化规律的了解。这对银河系乃至星系结构和演化规律的理解，都有重要的科学意义。

本项目开展了一批大振幅Delta Sct型变星、脉动白矮星、Gamma Dor/SPB型变星和疏散星团变星的星震学研究，并利用LAMOST和南极CSTAR、AST3等巡天项目取得的数据进行变星性质分析，同时，完成了主序变星和白矮变星的理论模型构建及其应用。通过这些研究工作，我们全面超额完成了任务书的研究内容，在拟研究的关键问题上取得了突破性进展，在恒星和恒星系统的星震学研究方面获得了一系列重要结果，发现了一批新的脉动变星，揭示了一批变星的脉动性质并确定了恒星参数，在星震学观测、数据处理及分析和理论模型构建等各方面完善了星震学研究平台。此外，我们利用国内中小口径光学望远镜、国际光学望远镜联测以及LAMOST和南极光学望远镜，取得了一大批变星的测光和光谱数据，对恒星星震学具有重要的科学价值。