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arXiv 1903.09313astro-ph.GA
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用Gaia DR2星表数据研究年轻疏散星团中的银河系动力学

Kinematics of the Galaxy from a Sample of Young Open Star Clusters with Data from the Gaia DR2 Catalogue

V. V. Bobylev, A. T. Bajkova

摘要:

我们选择了一个样本的326个年轻的$(\log t<8)$疏散星团的自行车和距离计算的不同作者从盖亚DR 2数据。它们的视线速度的平均值也取自各种出版物。作为我们运动学分析的结果,我们发现了以下银河系自转角速度的参数:$Ω_0=29.34\pm0.31$ km s $^{-1}$ kpc $^{-1}$,$Ω'_0=-4.012\pm0.074$ km s $^{-1}$ kpc $^{-2}$,和$Ω''_0=0.779\pm0.062$ km s $^{-1}$ kpc $^{-3}$ .对于采用的太阳银心距离$R_0=8.0\pm0.15$ kpc,太阳邻域绕银河系中心的圆自转速度为$V_0=235\pm5$ km s $^{-1}$。螺旋密度波产生的切向和径向速度扰动的幅度分别为$f_θ=3.8\pm1.2$ km s $^{-1}$和$f_R=4.7\pm1.0$ km s $^{-1}$;对于所采用的四臂螺旋模式,扰动波长分别为$λ_θ=2.3\pm0.5$ kpc和$λ_R=2.2\pm0.5$ kpc。太阳在螺旋密度波中的相位接近于$-120\pm10^\circ.$

英文摘要:

We have selected a sample of 326 young $(\log t<8)$ open star clusters with the proper motions and distances calculated by various authors from Gaia DR2 data. The mean values of their line-of-sight velocities have also been taken from various publications. As a result of our kinematic analysis, we have found the following parameters of the angular velocity of Galactic rotation: $Ω_0=29.34\pm0.31$ km s$^{-1}$ kpc$^{-1}$, $Ω'_0=-4.012\pm0.074$ km s$^{-1}$ kpc$^{-2}$, and $Ω''_0=0.779\pm0.062$ km s$^{-1}$ kpc$^{-3}$. The circular rotation velocity of the solar neighborhood around the Galactic center is $V_0=235\pm5$ km s$^{-1}$ for the adopted Galactocentric distance of the Sun $R_0=8.0\pm0.15$ kpc. The amplitudes of the tangential and radial velocity perturbations produced by the spiral density wave are $f_θ=3.8\pm1.2$ km s$^{-1}$ and $f_R=4.7\pm1.0$ km s$^{-1}$, respectively; the perturbation wavelengths are $λ_θ=2.3\pm0.5$ kpc and $λ_R=2.2\pm0.5$ kpc for the adopted four-armed spiral pattern. The Sun's phase in the spiral density wave is close to $-120\pm10^\circ.$

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