# Milky Way thin and thick disk kinematics with GAIA EDR3 and RAVE DR5

**Authors:** Katherine Vieira, Giovanni Carraro, Vladimir Korchagin, Artem Lutsenko, Terrence M. Girard, William van Altena  
**arXiv:** [2205.00590](https://arxiv.org/abs/2205.00590)  
**Date:** 2022-05-02  
**Summary page:** https://www.summarizepaper.com/en/paper/2205.00590v1/

## Key points

- Study by Katherine Vieira et al. analyzes Milky Way disk kinematics in solar neighborhood using GAIA DR3 data
- Focus on 278,228 red giant branch (RGB) stars within a cylindrical region around the Sun
- Two distinct kinematic components identified: thin disk and Thick disk
- Thin disk characterized by mean velocities of -1 km s$^{-1}$ in $V_R$, -239 km s$^{-1}$ in $V_{\phi}$, and 0 km s$^{-1}$ in $V_Z$
- Thin disk exhibits velocity dispersions of 31 km s$^{-1}$, 20 km s$^{-1}$, and 11 km s$^{-1}
- Thick disk shows mean velocities of +1 km s$^{-1}$ in $V_R$, -225 km s$^{-1}$ in $V_{\phi}$, and 0 km s$^{-1}$ in $V_Z
- Thick disk has larger velocity dispersions: 49 km s$^{-1}, 35 km s$^{-1}, and 22 km s$^{-1}
- Thick disk stars constitute about half of all stars up to heights of 500 parsecs above or below the galactic plane
- Presence of RGB stars with Thick disk kinematics suggests secular evolution processes shaping this component
- Detailed examination reveals asymmetries between Galactic hemispheres, providing insights into galactic dynamics and evolution

## Summary

In their study, Katherine Vieira, Giovanni Carraro, Vladimir Korchagin, Artem Lutsenko, Terrence M. Girard, and William van Altena present a comprehensive analysis of the kinematics of the Milky Way disk in the solar neighborhood using data from the GAIA DR3 catalog. <br>
 Focusing on a sample of 278,228 red giant branch (RGB) stars located within a cylindrical region centered at the Sun with a radius of 1 kiloparsec and a half-height of 0.5 kiloparsec, the researchers investigate the local kinematic properties of these stars to gain insights into the structure and dynamics of our galaxy. Their analysis reveals the presence of two distinct kinematic components within the stellar disk: the thin disk and the Thick disk. <br>
 The thin disk is characterized by mean velocities in radial ($V_R$), azimuthal ($V_{\phi}$), and vertical ($V_Z$) directions of approximately -1 km s$^{-1}$, -239 km s$^{-1}$, and 0 km s$^{-1}$ respectively. This component exhibits velocity dispersions ($\sigma_R$, $\sigma_{\phi}$, $\sigma_Z$) of 31 km s$^{-1}$, 20 km s$^{-1}$, and 11 km s$^{-1}$. On the other hand,<br>
the Thick disk displays mean velocities around +1 km s$^{-1}$ in $V_R$, -225 km s$^{-1}$ in $V_{\phi}$, and 0 km s$^{-1}$ in $V_Z$, accompanied by larger velocity dispersions of 49 km s$^{-1}$, 35 km s$^{-1}$, and 22 km s$^{-1}$. Notably, up to heights of 500 parsecs above or below the galactic plane, Thick disk stars constitute approximately half of all stars within this region. The significant presence of RGB stars exhibiting Thick disk kinematics suggests that <br>
 secular evolution processes may have played a crucial role in shaping this component of the Milky Way galaxy. By conducting a detailed examination of stellar kinematics in different Galactic hemispheres and identifying asymmetries between them, this study provides valuable insights into the complex dynamics and evolution of our galactic environment.