Different studies of the global pitch angle of the Milky Way's spiral arms

TL;DR

This study consolidates various measurements of the Milky Way's spiral arm pitch angles, using multiple statistical methods to determine a consistent mean value of approximately -13.1 degrees.

Contribution

It provides a comprehensive meta-analysis of existing data to establish a reliable global pitch angle for the Milky Way's spiral arms.

Findings

Mean global pitch angle is -13.1 degrees

Statistical methods yield consistent results

Wide previous distribution of individual measurements

Abstract

There are many published values for the pitch angle of individual spiral arms, and their wide distribution (from -3 to -28 degrees) begs for various attempts for a single value. Each of the four statistical methods used here yields a mean pitch angle in a small range, between -12 and -14 degrees (table 7, figure 2). The final result of our meta-analysis yields a mean global pitch angle in the Milky Way's spiral arms of -13.1 degrees, plus or minus 0.6 degree.