# Vertical Distribution and Kinematics of Planetary Nebulae in the Milky Way

## TL;DR

This study analyzes the distribution and movement of planetary nebulae in the Milky Way, estimating their total number, vertical scale height, and confirming the need to adjust distance scales for accuracy.

## Contribution

It provides a complete sample of PNe within 2 kpc, estimates the total PNe in the Galaxy, and refines the distance scale and vertical distribution parameters.

## Key findings

- Total PNe in Galaxy: approximately 17,000
- Vertical scale height of thin disk: about 197 pc
- Distance scale reduction of ~20% improves consistency

## Abstract

Based on published data, we have produced a sample of planetary nebulae (PNe) that is complete within 2 kpc of the Sun. We have estimated the total number of PNe in the Galaxy from this sample to be 17000+/-3000 and determined the vertical scale height of the thin disk based on an exponential density distribution to be 197+/-10 pc. The next sample includes PNe from the Stanghellini-Haywood catalog with minor additions. For this purpose, we have used about 200 PNe with Peimbert's types I, II, and III. In this case, we have obtained a considerably higher value of the vertical scale height that increases noticeably with sample radius. We have experimentally found that it is necessary to reduce the distance scale of this catalog approximately by 20%. Then, for example, for PNe with heliocentric distances less than 4 kpc the vertical scale height is 256+/-12 kpc. A kinematic analysis has confirmed the necessity of such a reduction of the distance scale.