The spiral structure in the Solar neighborhood

TL;DR

This paper reviews recent observational progress in mapping the Solar neighborhood's spiral structure, combining data from various tracers to delineate arm segments and identify substructures like spurs.

Contribution

It provides an updated depiction of nearby spiral arms using a large dataset with improved distance accuracy, including analysis of substructures such as spurs.

Findings

Five spiral arm segments are traced and characterized.

Updated parameters for the nearby spiral arms are provided.

Substructures like spurs or feathers are identified and discussed.

Abstract

The spiral structure in the Solar neighborhood is an important issue in astronomy. In the past few years, there is significant progress in observation. The distances for a large number of good spiral tracers, i.e. giant molecular clouds, high-mass star-formation region masers, HII regions, O-type stars and young open clusters, have been accurately estimated, making it possible to depict the detailed properties of nearby spiral arms. In this work, we first give an overview about the research status for the Galaxy's spiral structure based on different types of tracers. Then the objects with distance uncertainties better than 15\% and $<$0.5 kpc are collected and combined together to depict the spiral structure in the Solar neighborhood. Five segments related with the Perseus, Local, Sagittarius-Carina, Scutum-Centaurus and Norma Arms are traced. With the large dataset, the parameters of the nearby arm segments are fitted and updated. Besides the dominant spiral arms, some substructures probably related to arm spurs or feathers are also noticed and discussed.