Kinematics of high-velocity stars utilizing LAMOST and Gaia DR3 archives within 100 kpc

Abstract

The kinematic parameters identified from high-velocity stars situated within $\sim100$ kpc are examined and analyzed. We included three high-velocity programs comprising 591, 87, and 519 stars as a function of distances ranging from $0.10$ to nearly $109$ kpc. In this analysis, we will determine the spatial velocities $(U, V, W)$ in galactic coordinates along with their velocity dispersion $(\sigma_1, \sigma_2, \sigma_3)$, the convergent point $(A_o, D_o)$, and therefore, the solar motion $(S_\odot)$. In conclusion, we are calculating the first Oort constant: $A = 11.94 \pm 0.29 \text{ km s}^{-1} \text{ kpc}^{-1}$, and the second one: $B = -17.78 \pm 0.24 \text{ km s}^{-1} \text{ kpc}^{-1}$. The angular rotation rate is given by: $|A - B| = 25.07 \pm 5.01 \text{ km s}^{-1} \text{ kpc}^{-1}$, and the average rotational velocity: $V_o = 243.72 \pm 15.61 \text{ km s}^{-1}$.