Kinematic Analysis of Solar-Neighborhood Stars Based on RAVE4 Data

TL;DR

This study analyzes the kinematic properties of nearby stars using RAVE4 data, revealing new features in their velocity distributions and refining key Galactic rotation parameters.

Contribution

It provides updated kinematic parameters for solar neighborhood stars and uncovers previously unknown velocity distribution features.

Findings

Refined solar neighborhood kinematic parameters.

Detected new peaks in the velocity distribution.

Revealed an enhanced branch near the Wolf 630 peak.

Abstract

We consider stars with radial velocities, proper motions, and distance estimates from the RAVE4 catalogue. Based on a sample of more than 145000 stars at distances $r<0.5$~kpc, we have found the following kinematic parameters: (U,V,W)_\odot=(9.12, 20.80, 7.66)\pm(0.10, 0.10, 0.08) km s^{-1}, \Omega_0=28.71\pm0.63 km s^{-1} kpc^{-1}, and \Omega'_0=-4.28\pm0.11 km s^{-1} kpc^{-2}. This gives the linear rotation velocity V_0=230\pm12 km s^{-1} (for the adopted R_0= 8.0\pm0.4 kpc) and the Oort constants A=17.12\pm0.45 km s^{-1} kpc^{-1} and B=-11.60\pm0.77 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 \sim 47000 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.