Chronostar. II. Kinematic age and substructure of the Scorpius-Centaurus OB2 association
Abstract
The nearest region of massive star formation - the Scorpius-Centaurus OB2 association (Sco-Cen) - is a local laboratory ideally suited to the study of a wide range of astrophysical phenomena. Precision astrometry from the Gaia mission has expanded the census of this region by an order of magnitude. However, Sco-Cen's vastness and complex substructure make kinematic analysis of its traditional three regions, Upper Scorpius, Upper Centaurus-Lupus and Lower Centaurus-Crux, challenging. Here we use Chronostar, a Bayesian tool for kinematic age determination, to carry out a new kinematic decomposition of Sco-Cen using full 6-dimensional kinematic data. Our model identifies 8 kinematically distinct components consisting of 8,185 stars distributed in dense and diffuse groups, each with an independently-fit kinematic age; we verify that these kinematic estimates are consistent with isochronal ages. Both Upper Centaurus-Lupus and Lower Centaurus-Crux are split into two parts. The kinematic age of the component that includes PDS 70, one of the most well studied systems currently forming planets, is 153 Myr.
Keywords
Cite
@article{arxiv.2111.09897,
title = {Chronostar. II. Kinematic age and substructure of the Scorpius-Centaurus OB2 association},
author = {Maruša Žerjal and Michael J. Ireland and Timothy D. Crundall and Mark R. Krumholz and Adam D. Rains},
journal= {arXiv preprint arXiv:2111.09897},
year = {2022}
}
Comments
Submitted to MNRAS. 19 pages, 9 figures