1999/07/05 by Javier Ballesteros-Paredes, Javier Ballesteros‐Paredes, Lee Hartmann +2 · 312 citations
Chemistry · Earth and Planetary Sciences · Physics and Astronomy · #Astrophysics #Astrophysics and Star Formation Studies #Atmospheric Ozone and Climate #Flow (mathematics) #Galaxy #Geometry #Halo #Interstellar cloud #Interstellar medium #Line (geometry) #Magnetohydrodynamics #Mechanics #Molecular Spectroscopy and Structure #Molecular cloud #Physics #Plasma #Stars #T Tauri star #Turbulence #astro-ph
paper · pdf · doi:10.1086/308076
published in The Astrophysical Journal 527(1), 285-297 (IOP Publishing) · 26 pages, 12 ps figures. Apj accepted
arxiv created 1999/07/05 · openalex publication_date 1999/12/10 · arxiv updated 2010/04/06 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/08
We suggest that molecular clouds can be formed on short timescales by compressions from large scale streams in the interstellar medium (ISM). In particular, we argue that in the Taurus-Auriga complex, with filaments of 10-20 × 2-5 pc, most have been formed by H I flows in ≲3 Myr, explaining the absence of post-T Tauri stars in the region with ages ≳3 Myr. Observations in the 21 cm line of the H I "halos" around the Taurus molecular gas show many features (broad asymmetric profiles, velocity shifts of H I relative to 12 CO) predicted by our MHD numerical simulations, in which large-scale H I streams collide to produce dense filamentary structures. This rapid evolution is possible because the H I flows producing and disrupting the cloud have much higher velocities (5-10 km s -1 ) than are present in the molecular gas resulting from the colliding flows. The simulations suggest that such flows can occur from the global ISM turbulence without requiring a single triggering event such as a supernova explosion.