2018/02/20 by Konstantin V. Getman, Michael A. Kuhn, Eric D. Feigelson +4 · 2 citations
Chemistry · Physics and Astronomy · #Astronomy #Astrophysics #Astrophysics and Star Formation Studies #Cluster (spacecraft) #Molecular Spectroscopy and Structure #Molecular cloud #Physics #Population #RADIUS #Star cluster #Star formation #Stars #Stellar, planetary, and galactic studies #Young stellar object #astro-ph.GA #astro-ph.SR
paper · pdf · doi:10.1093/mnras/sty473
Accepted for publication in MNRAS (on February 19, 2018); 30 pages, 14 figures, and 8 tables
openalex publication_date 2018/02/20 · arxiv created 2018/04/13 · arxiv updated 2018/05/02 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
The SFiNCs (Star Formation in Nearby Clouds) project is an X-ray/infrared study of the young stellar populations in 22 star forming regions with distances <=1 kpc designed to extend our earlier MYStIX survey of more distant clusters. Our central goal is to give empirical constraints on cluster formation mechanisms. Using parametric mixture models applied homogeneously to the catalog of SFiNCs young stars, we identify 52 SFiNCs clusters and 19 unclustered stellar structures. The procedure gives cluster properties including location, population, morphology, association to molecular clouds, absorption, age (AgeJX), and infrared spectral energy distribution (SED) slope. Absorption, SED slope, and AgeJX are age indicators. SFiNCs clusters are examined individually, and collectively with MYStIX clusters, to give the following results. (1) SFiNCs is dominated by smaller, younger, and more heavily obscured clusters than MYStIX. (2) SFiNCs cloud-associated clusters have the high ellipticities aligned with their host molecular filaments indicating morphology inherited from their parental clouds. (3) The effect of cluster expansion is evident from the radius-age, radius-absorption, and radius-SED correlations. Core radii increase dramatically from ~0.08 to ~0.9 pc over the age range 1--3.5 Myr. Inferred gas removal timescales are longer than 1 Myr. (4) Rich, spatially distributed stellar populations are present in SFiNCs clouds representing early generations of star formation. An Appendix compares the performance of the mixture models and nonparametric Minimum Spanning Tree to identify clusters. This work is a foundation for future SFiNCs/MYStIX studies including disk longevity, age gradients, and dynamical modeling.