V型小行星基础物理性质观测研究

V-type asteroids are usually connected with the asteroid (4) Vesta. The studies on their distribution, formation and evolution can provide us with the important clues on the evolution of asteroids. The questions on whether some V-type asteroids originated from other parent bodies than (4) Vesta and on how the V-type near-earth asteroids had evolved have become the hotspot on the researches of small Solar System bodies. For the V-type asteroids, it is significantly important to answer these questions by the studies of their fundamental physical properties such as rotation properties, size, shape, internal structure and surface material properties. However, these fundamental physical properties are poorly restricted, due to the limited number of V-type asteroids which have been studied and observed. In this project, using the small- and medium-sized ground-based optical telescopes, the rotation periods, shapes, spin vectors and photometric phase curves of these selected V-type asteroids are obtained by their lightcurves in the photometric observations, and the number of research sample is expanded. By the analysis on the spin states of the Vesta asteroid family members and studies on the photometric phase curves of the V-type asteroids, the understandings on the evolution of V-type asteroids are deepened. In our project, the direct detections of YORP effect will be carried out firstly for the V-type near-earth asteroids, in order to increase the number of detected objects and provide more observational evidence for the influence of YORP effect on the evolution of asteroids.

V型小行星常与第四号小行星灶神星（Vesta）联系在一起。V型小行星的分布、形成与演化研究为我们理解小行星演化提供了重要线索。而某些V型小行星是否源自于灶神星以外的其他母体、V型近地小行星经历过怎样的演化历程等问题都已成为当前太阳系小天体研究热点。V型小行星基础物理性质（诸如自转特性、大小、形状、内部结构、表面物质性质等）研究对于解答这些疑问具有重要意义，但目前相关观测与研究还十分匮乏。在本项目中，我们将主要利用中小型光学望远镜，对V型小行星进行测光观测，通过光变曲线的分析，获得其自转周期、形状、自转轴指向以及测光相位曲线等基础物理性质，扩大V型小行星基础物理性质研究样本；讨论Vesta小行星族成员是否处于Slivan状态；系统地对V型小行星测光相位曲线进行研究。本项目还将首次对由YORP效应所引起的V型近地小行星自转特性变化进行探测，为YORP效应对于小行星演化影响提供更多观测证据。

太阳系小天体的物理、化学性质蕴藏了太阳系早期环境信息，是揭示太阳系形成与演化的关键“钥匙”。特别是对于大部分V型小天体而言，它们常与古铜钙长无球粒-钙长辉长-奥长古铜无球粒陨星（HED meteorite）以及居于内主带区域中的Vesta小行星族群联系在一起，从而能为内太阳的演化历程提供重要的线索。我们利用中小口径望远镜，重点对Vesta小行星族群成员以及其周边区域小天体开展多色测光观测；并对V型小行星自转特性进行了分析研究；以及讨论了YORP效应探测和扩展了对内主带其他区域中小天体自转状态的研究。