Kinematics Of Solar Neighborhood Stars

After the Hipparcos satellite was launched in 1989, it has opened a gate for as-trometry. High-precision positions, proper motions and distances brought us possi-bilities in the study of Galactic structure and evolution. The launch of the second astrometric satellite Gaia early in this year, would further push the astrometry into the "micro-arcsec era". At that time, much more high-precision trigonometric parallaxes are going to be obtained as well as radial velocities and spectra. The alternation of the two generations of telescopes demands that we must focus on collecting what have been done and prepare for the upcoming. This paper consists of four main sections: First of all, we begin by briefly introducing some basic astrometric concepts. Then we demonstrate two part of works that has been done:1. Build a star catalogue 2. Cal-culate Galactic constants and study Galactic evolution. In the last section, we envision the possible achievements that Gaia will bring.The first chapter introduces several common measurements, including definition and observing methods. It provides a reference when the choice between different data sources or revisions of data are needed. Meanwhile, a few recent comprehensive catalogues and kinematical analysis are also included.The second chapter is mainly about building a catalogue with astrophysical data — The Astrometric catalogue associated with Astrophysical Data (hereafter denoted as ACAD). This paper targets on collecting the F and G type stars. It contains astrometric data, photometric data and age (metallicity) data. Considering the accuracy and con-sistency in the data from different sources,8 catalogues were selected to construct the final catalogue — ACAD. There are 27,553 stars in ACAD. All the stars have three-dimensional positions, space velocities (three-dimensional velocities) and at least one type of astrophysical data (age or metallicity).The third chapter calculates the solar motion and Oort constants in different age (metallicity) bins using the Lindblad-Oort Model with the age and metallicity data from ACAD. In this way, the evolution of kinematical parameters with time and the co-relation between kinematical parameters and metallicity gradient were investigated directly without the pre-conditions, which are needed if the analysis is based on col-ors and velocity dispersions. The results show that the random motions are becoming stronger with time, which means the disk is heated continuously. The component of the solar motion in the direction of Galactic rotation (S2) has a linear increase with respect to age. It may be a consequence of the scattering processes which were con-sidered as one of the main mechanism of disk heating. By extrapolating, S2 for the galactic dynamical cold disk was estimated to be 7.95 km s-1. It fits with the results from previous work, however, still gets influenced by spiral structure, which means S2 might be underestimated. Si,S2 also increase linearly with respect to metallicity, which proves that radial migration is one of the main causes of metallicity gradient in solar neighborhood. Meanwhile, we believe stellar migration has a stronger influence in the radial direction than in the direction of Galactic rotation. The Local Standard of Rest (LSR) calculated from stars of different ages or metallicities does not systemati-cally affect the estimated value of the rotational velocity of the Sun around the galactic centre.Chapter 4 discusses the conclusions, gives an outline of the next version of A-CAD and introduce the possibilities Gaia will bring us. Before the Gaia data formally released, there are decades for us to collect and organize the high-precision data. An-alyzing the collected data will not only expand our knowledge of the Galaxy, but also be used as a comparison.