论文标题
根据Gaia Dr2数据，关于恒星在pleiades中的运动
On the Motion of Stars in the Pleiades according to Gaia DR2 Data
论文作者
论文摘要
我们使用GAIA DR2数据来估计pleiades的参数。 With the data on stars with m_G<=18 mag, we constructed the density maps and profile, luminosity and mass functions, determined the cluster radius, 10.9+/-0.3 deg (26.3+/-0.7 pc), and the radius of its core, 2.62 deg (6.24 pc), and obtained estimates for the number of stars in the cluster, 1542+/-121, and their mass, 855+/-104 solar 大量的。在R_S <1 pc的三维空间和R_S 〜1.4-5 PC中，在距离群集中心距离群集中心的恒星分布在R_S距离R_S上分布。我们确定了群集v_c = 0.56 +/- 0.07 km/s的核心的平均“旋转速度”在距其中心的距离d <= 4.6 pc的距离D时。群集核心在距其中心d〜5.5 pc的距离的旋转速度接近零：v_c = 0.1 +/- 0.3 km/s。群集在距其中心d〜7.1 pc的“逆行”旋转的速度为v_c = 0.48 +/- 0.20 km/s。距离D到群集中心距离d的天空平面中簇核心恒星速度的模量的模量依赖性包含周期性振荡。群集核心星的速度分散体的平均增加随R_S的增加而增加，R_S的速度分散量和径向密度波和天空平面中速度场的振荡波一样，表明常规场中簇的非平稳性。簇芯中的牛仔裤波长减小，考虑到银河系重力场后，牛仔裤不稳定性下核心恒星的速度分散增加。 PLEIADES簇中的重力不稳定区域位于R_S间隔= 2.2-5.7 PC中，并包含所考虑样品中恒星总数的39.4-60.5％。
We used Gaia DR2 data in order to estimate parameters of the Pleiades. With the data on stars with m_G<=18 mag, we constructed the density maps and profile, luminosity and mass functions, determined the cluster radius, 10.9+/-0.3 deg (26.3+/-0.7 pc), and the radius of its core, 2.62 deg (6.24 pc), and obtained estimates for the number of stars in the cluster, 1542+/-121, and their mass, 855+/-104 solar mass. Distribution of stars with m_G<16 mag at distances r_s from the cluster center in three-dimensional space of r_s<1 pc and at r_s~1.4-5 pc contains radial density waves. We determined the average `prograde' rotation velocity of the core of the cluster v_c=0.56+/-0.07 km/s at distances d in the sky plane d<=4.6 pc from its center. The rotation velocity of the cluster core at a distance of d~5.5 pc from its center is close to zero: v_c=0.1+/-0.3 km/s. The velocity of the `retrograde' rotation of the cluster at a distance of d~7.1 pc from its center is v_c=0.48+/-0.20 km/s. The dependences of moduli of the tangential and radial components of the cluster core star velocities in the sky plane on the distance d to the cluster center contain the periodic oscillations. The velocity dispersions of the cluster core stars increase on average with an increase in r_s, which, like the radial density waves and the waves of oscillations of the velocity field in the sky plane, indicates the non-stationarity of the cluster in the regular field. The Jeans wavelength in the cluster core decreases, and the velocity dispersion of the core stars under the Jeans instability increases after taking into account the Galactic gravitational field. The region of gravitational instability in the Pleiades cluster is located in the interval r_s=2.2-5.7 pc and contains 39.4-60.5% of the total number of stars in the considered samples.
