Kinematics of the Galaxy from a Sample of Young Open Star Clusters with Data from the Gaia DR2 Catalogue. (arXiv:1903.09313v1 [astro-ph.GA])
<a href="http://arxiv.org/find/astro-ph/1/au:+Bobylev_V/0/1/0/all/0/1">V.V. Bobylev</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bajkova_A/0/1/0/all/0/1">A.T. Bajkova</a>
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: $Omega_0=29.34pm0.31$ km s$^{-1}$ kpc$^{-1}$, $Omega'_0=-4.012pm0.074$ km s$^{-1}$ kpc$^{-2}$, and $Omega''_0=0.779pm0.062$ km s$^{-1}$ kpc$^{-3}$. The circular rotation velocity of the solar neighborhood around the Galactic center is $V_0=235pm5$ km s$^{-1}$ for the adopted Galactocentric distance of the Sun $R_0=8.0pm0.15$ kpc. The amplitudes of the tangential and radial velocity perturbations produced by the spiral density wave are $f_theta=3.8pm1.2$ km s$^{-1}$ and $f_R=4.7pm1.0$ km s$^{-1}$, respectively; the perturbation wavelengths are $lambda_theta=2.3pm0.5$ kpc and $lambda_R=2.2pm0.5$ kpc for the adopted four-armed spiral pattern. The Sun's phase in the spiral density wave is close to $-120pm10^circ.$
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:
$Omega_0=29.34pm0.31$ km s$^{-1}$ kpc$^{-1}$, $Omega’_0=-4.012pm0.074$ km
s$^{-1}$ kpc$^{-2}$, and $Omega”_0=0.779pm0.062$ km s$^{-1}$ kpc$^{-3}$. The
circular rotation velocity of the solar neighborhood around the Galactic center
is $V_0=235pm5$ km s$^{-1}$ for the adopted Galactocentric distance of the Sun
$R_0=8.0pm0.15$ kpc. The amplitudes of the tangential and radial velocity
perturbations produced by the spiral density wave are $f_theta=3.8pm1.2$ km
s$^{-1}$ and $f_R=4.7pm1.0$ km s$^{-1}$, respectively; the perturbation
wavelengths are $lambda_theta=2.3pm0.5$ kpc and $lambda_R=2.2pm0.5$ kpc
for the adopted four-armed spiral pattern. The Sun’s phase in the spiral
density wave is close to $-120pm10^circ.$
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