# The age-kinematical features in the Milky Way outer disk

## TL;DR

This study analyzes the vertical kinematics of the Milky Way's outer disk using red clump stars, revealing age-dependent warp features likely caused by infalling misaligned gas.

## Contribution

It provides the first detailed measurement of age-dependent vertical motions in the Galactic warp using a large stellar sample.

## Key findings

- Younger stars show larger vertical bulk motions than older stars.
- The warp is mainly contributed by younger stars.
- Results support a warp formation scenario from infalling misaligned gas.

## Abstract

We derive the mean velocity components at various Galactocentric radii from 8 to 14 kpc using about 40,000 red clump stars observed in the LAMOST survey. We find that the vertical bulk motion for younger red clump stars are significantly larger than that for the older red clump stars. This is likely the kinematical feature of the Galactic warp around its line-of-node, which is located close to the Galactic anti-center region. It is evident that the warp are mainly contributed by the younger stars rather than the older stars. The age variation in the vertical kinematics favors a formation scenario where the Galactic warp is originated from infalling misaligned gas.