双星和多星系统的星周尘埃碎片盘

Almost half of stars belong to binary or multiple systems in our Galaxy. Due to the successful operation of Kepler space telescope, the extrasolor planets have been detected in over 100 binaries and multiple stars. The circumbinary or circumstellar dust disks may be the cradles of planets, and certainly exist in the binary and multiple star systems. The dust grains in the disk absorb the starlight from the central star and then radiate this energy away in the infrared wavelengths. This project aims to the dust debris disks around the binary and multiple star systems. We construct the observed sample of the binary and multiple star systems with the radiations from the infrared to sub-millimeter wavelengths. By spectroscopically and photometrically observing binaries and multiple stars, we can accurately determine their physical parameters and evolutionary states. Considered these stellar parameters as the input ones, we construct the infrared radiation model for the dust disk in order to investigate the spatial distribution of the disk, the size distribution, composition, mass of dust grains, and study the dynamical evolution of disk. We finally can search for the correlations between the characteristics of the debris disk and its dust grains, and the properties of extrasolar planets in binaries and multiple stars (whether or not the existence of exoplanets). We think that this project is very important for us to know the characteristics of dust debris disks, the formation and evolution of planets, and the key role of debris disks and planets in the evolution in binaries and multiple stars.

银河系中几乎一半的恒星是双星或多星系统。由于Kepler卫星的成功运行，系外行星在100多颗双星或多星系统中被探测到。星周尘埃盘是行星的发源地，因此星周尘埃盘也会存在于双星和多星系统中，尘埃受星光加热亦会在红外波段辐射出去。本项目以双星和多星系统的星周尘埃碎片为研究对象，开展以下四方面的工作:(1)构建具有红外和毫米波辐射的双星和多星系统观测样本;(2)通过对这些样本星的光谱和测光观测，精确定出这些双星和多星系统的物理参数及其演化状态;(3)以这些恒星参数为输入参数，构建尘埃盘的红外辐射模型，研究其尘埃盘的空间分布，尘埃的尺寸、组份、质量及其动力学演化;(4)最终探索出尘埃碎片盘及其尘埃的特性与双星多星系统的系外行星特性（或是否存在系外行星）之间的关系。这对我们了解尘埃碎片盘的特性、行星形成和演化、以及尘埃盘和行星在双星和多星系统演化中的作用具有重要作用。

银河系中几乎一半的恒星是双星或多星系统。星周尘埃盘也会存在于双星和多星系统中，尘埃受星光加热也会在红外波段辐射出去。我们利用国内中小口径望远镜对十八颗样本星进行光谱和测光观测，确定了双星系统的物理参数（如质量、半径、有效温度和光度等）和演化状态。我们研究发现六颗双星（V2364 Cyg、EG Cas、 CT Tau、GU Mon 和 V701 Sco）存在红外超，其中V701 Sco在11.6微米、14.5微米和22.1微米的红外超可以明显表现出有尘埃盘红外辐射。基于轨道周期变化，发现八颗双星可能有系外伴星存在强烈的磁活动。在充分考虑尘埃的空间分布、尘埃的尺寸和组份等，我们构建绕双星尘埃盘的红外辐射模型。以Algol星食双星alpha CrB的红外辐射为例，我们对其进行模拟并得到尘埃盘的内半径在50AU，尘埃的峰值在240AU，尘埃的总质量为0.037个月球质量。最后我们讨论了尘埃的形成、系外伴星及他们对尘埃盘在双星多星系统演化中的作用。