The solar Galactocentric distance and local kinematic parameters from Gaia DR3 using Bottlinger's equations

RESUMO

The solar Galactocentric distance, $R_0$, together with the local kinematic parameters of the Milky Way, provides fundamental constraints on the Galactic structure and rotation. Their accurate determination has become possible with the hight astrometric precision of Gaia DR3 catalogue. We determine the Galactocentric distance, the Solar peculiar motion components $(u_0,v_0,w_0)$, and the local angular velocity of Galactic rotation, $\omega_0$, using a self-consistent approach based on Bottlinger's equations within a nonlinear least-squares framework. Bottlinger's equations were applied to approximately 13 million luminous giant stars $(M_G<4)$ selected from Gaia DR3. The analysis was carried out for two subsamples: a thin disk dominated sample (|z|<0.5 kpc) and a mixed thin and thick disk sample (|z|<1.0 kpc). The kinematic parameters were estimated using a nonlinear generalized least-squares method. We obtained $R_0=8.165\pm0.024$kpc and a local angular velocity of Galactic rotation $\omega_0=28.477\pm0.002$ km/s/kpc for the thin disk dominated sample. The Solar peculiar motion components are $(u_0,v_0,w_0)=(9.261\pm0.006,16.593\pm0.008,7.686\pm0.008)$km/s. Including mixed thin and thick disk stars resulted in a systematic shift in $R_0$, yielding $R_0=8.333\pm0.022$kpc, while the Solar peculiar motion and local angular velocity remain consistent within uncertainties. The Galactic kinematic parameters derived are consistent with recent independent determinations. The Solar peculiar motion parameters and the local angular velocity remain stable for different vertical selections, the recovered Galactocentric distance exhibits a systematic dependence on the adopted stellar sample, indicating that the vertical structure of the tracer population should be taken into account when determining $R_0$.