Kinematic analysis of solar-neighborhood stars based on RAVE4 data

Abstract

We consider stars with radial velocities, proper motions, and distance estimates from the RAVE4 catalogue. Based on a sample of more than 145 000 stars at distances r < 0.5 kpc, we have found the following kinematic parameters: \({\left( {U,{\kern 1pt} V,{\kern 1pt} W} \right)_ \odot }\) = (9.12, 20.80, 7.66) ± (0.10, 0.10, 0.08) km s⁻¹, Ω₀ = 28.71 ± 0.63 km s⁻¹ kpc⁻¹, and Ω₀^’ = −4.28 ± 0.11 km s⁻¹ kpc⁻². This gives the linear rotation velocity V₀ = 230 ± 12 km s⁻¹ (for the adopted R₀ = 8.0 ± 0.4 kpc) and the Oort constants A = 17.12 ± 0.45 km s⁻¹ kpc⁻¹ and B = −11.60 ± 0.77 km s⁻¹ kpc⁻¹. The 2D velocity distributions in the UV, UW, and VW planes have been constructed using a local sample, r < 0.25 kpc, consisting of ~47 000 stars. A difference of the UV velocity distribution from the previously known ones constructed from a smaller amount of data has been revealed. It lies in the fact that our distribution has an extremely enhanced branch near the Wolf 630 peak. A previously unknown peak at (U, V) = (−96, −10) km s⁻¹ and a separate new feature in the Wolf 630 stream, with the coordinates of its center being (U, V) = (30, −40) km s⁻¹, have been detected.