2006/09/25 by Lee Hartmann, Andreas Burkert · 7 citations
Physics and Astronomy · #Astro and Planetary Science #Astronomy #Astrophysics #Astrophysics and Star Formation Studies #Cluster (spacecraft) #Gravitation #Gravitational collapse #Molecular cloud #Nebula #Orion Nebula #Physics #Protein filament #Star formation #Stars #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1086/509321
published as Astrophys.J.654:988-997,2007 · 23 pages, 6 figures, to appear in the Astrophysical Journal
arxiv created 2006/09/25 · openalex publication_date 2007/01/10 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We suggest that the Orion A cloud is gravitationally collapsing on large scales, and is producing the Orion Nebula Cluster through the focusing effects of gravity acting within a finite cloud geometry. In support of this suggestion, we show how an elliptical rotating sheet of gas with a modest density gradient along the major axis can collapse to produce a structure qualitatively resembling Orion A, with a fan-shaped structure at one end, ridges or filaments along the fan, and a narrow curved filament at the other end reminiscent of the famous integral-shaped filament. The model produces a local concentration of mass within the narrow filament, which in principle could form a dense cluster of stars like that of the Orion Nebula. We suggest that global gravitational contraction might be a more common feature of molecular clouds than previously recognized, and that the formation of star clusters is a dynamic process resulting from the focusing effects of gravity acting on the geometry of finite clouds.