# Parallaxes for star forming regions in the inner Perseus spiral arm

## TL;DR

This study measures precise parallaxes and proper motions of masers in high-mass star-forming regions to map their locations and motions within the Perseus spiral arm of the Milky Way.

## Contribution

It provides new high-precision distance and motion data for star-forming regions in the Perseus arm, enhancing Galactic structure models.

## Key findings

- Mapped the positions of star-forming regions in the Perseus arm.
- Identified clustering of regions between 30° and 50° Galactic longitude.
- Revealed a scarcity of such sources between 50° and 90° longitude.

## Abstract

We report trigonometric parallax and proper motion measurements of 6.7-GHz CH3OH and 22-GHz H2O masers in eight high-mass star-forming regions (HMSFRs) based on VLBA observations as part of the BeSSeL Survey. The distances of these HMSFRs combined with their Galactic coordinates, radial velocities, and proper motions, allow us to assign them to a segment of the Perseus arm with ~< 70 deg. These HMSFRs are clustered in Galactic longitude from ~30 deg to ~50, neighboring a dirth of such sources between longitudes ~50 deg to ~90 deg.