Cygnus OB2 DANCe: A high-precision proper motion study of the Cygnus OB2 association
- Wright
DOIAbstract
We present a high-precision proper motion study of 873 X-ray and spectroscopically selected stars in the massive OB association Cygnus OB2 as part of the DANCe project. These were calculated from images spanning a 15 yr baseline and have typical precisions <1 mas yr-1. We calculate the velocity dispersion in the two axes to be sa(c)=13.0+0.8-0.7 and sd(c)=9.1+0.5-0.5?km?s-1, using a two-component, two-dimensional model that takes into account the uncertainties on the measurements. This gives a three-dimensional velocity dispersion of s3D = 17.8 ± 0.6?km?s-1 implying a virial mass significantly larger than the observed stellar mass, confirming that the association is gravitationally unbound. The association appears to be dynamically unevolve...
Add to ORKG