发表机构
Programme of Astronomy and Space Sciences, Institute of Graduate Studies in Science, Istanbul University; Department of Astronomy and Space Sciences, Faculty of Science, Istanbul University; Homer L. Dodge Department of Physics and Astronomy, University of Oklahoma（伊斯坦布尔大学; 伊斯坦布尔大学; 俄克拉荷马大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
该研究利用SDSS DR19和Gaia DR3数据分析5837颗DA型白矮星，明确其以薄盘为主，推导银盘结构参数，证实白矮星可作为银河系演化的示踪物。
AI 中文摘要
我们对5837颗具有SDSS DR19光谱数据和Gaia DR3天体测量数据的DA型白矮星开展了全面的运动学与动力学分析。利用互补的空间分布、运动学性质和轨道参数，我们发现该样本绝大多数由薄盘恒星构成，厚盘和银晕的贡献仅占很小比例。速度弥散和轨道偏心率从薄盘到银晕系统性增大，反映出银族天体的温度逐渐升高。4829颗白矮星的总恒星年龄数据揭示出清晰的年龄-速度弥散关系，其幂律指数为0.06-0.17，证实白矮星保留了银盘长期动力学加热的历史。我们推导得出薄盘的标高为123-229秒差距，径向标长为3.2-3.5千秒差距；厚盘的标高为865秒差距，约占本地恒星密度的6-7%。重建的诞生半径表明，导星半径的变化是当前附近白矮星径向重新分布的重要组成部分，不过径向迁移和轨道模糊效应对位移的相对贡献无法通过这些位移测量唯一区分。这些结果确立了白矮星作为银河系运动学、动力学和结构演化的强大示踪物的地位。
英文摘要
We present a comprehensive kinematic and dynamical analysis of 5,837 DA white dwarfs with SDSS DR19 spectroscopy and Gaia DR3 astrometry. Using complementary spatial distributions, kinematic properties, and orbital parameters, we show that the sample is overwhelmingly dominated by the thin disk, with only minor contributions from the thick disk and the halo. Velocity dispersions and orbital eccentricities increase systematically from the thin disk to the halo, reflecting progressively hotter Galactic populations. Total stellar ages available for 4,829 white dwarfs reveal a clear age-velocity dispersion relation with power-law indices of 0.06-0.17, confirming that white dwarfs preserve the secular dynamical heating history of the Galactic disk. We derive a thin-disk scale-height of 123-229 pc and radial scale-length of 3.2-3.5 kpc, while the thick disk has a scale height of 865 pc and contributes approximately 6-7 % of the local stellar density. Reconstructed birth radii indicate that changes in the guiding radii represent an important component of the present-day radial redistribution of nearby white dwarfs, although the relative contributions of radial migration and orbital blurring cannot be uniquely separated from these displacement measures. These results establish white dwarfs as powerful tracers of the kinematic, dynamical, and structural evolution of the Milky Way.
Comments24 pages, including 11 figures and 7 tables, accepted for publication in The Astronomical Journal
