3D Rotation of the Open Cluster NGC 2516

TL;DR

This study combines Gaia data and spectroscopic measurements to determine the three-dimensional rotation of the open cluster NGC 2516, revealing its rotation axis and velocity, and comparing it with other clusters to explore rotational properties.

Contribution

The paper presents the first detailed 3D rotation measurement of NGC 2516 using combined astrometric and spectroscopic data, and analyzes its rotation axis and velocity in relation to other clusters.

Findings

Median rotational velocity of 0.12 km/s

Rotation axis inclined at 74 degrees to the galactic plane

Rotation rate inconsistent with age and mass dependence

Abstract

We have combined Gaia astrometry with Gaia-ESO Survey radial velocities to measure the 3D rotation of the open cluster NGC 2516. We compiled a sample of 430 members with astrometry and spectroscopy and use these to determine a distance to the cluster of 406.3 +/- 0.8 pc, which we then use to infer the 3D positions and velocities of all stars in the cluster using a Bayesian model. We identify the axis of maximum cluster rotation and measure a median rotational velocity of 0.12 +/- 0.02 km/s. We find the axis of maximum cluster rotation to be 74 +/- 17 degrees to the plane of our galaxy. We compare this rotation rate to measurements of cluster rotation in other open clusters and find that it is inconsistent with the expected dependences on cluster age and mass.