2007/03/08 by S. Kitsionas, A. P. Whitworth · 1 citation
Physics and Astronomy · #Astro and Planetary Science #Astrophysics and Star Formation Studies #Dust and Plasma Wave Phenomena #astro-ph
paper · pdf · doi:10.1111/j.1365-2966.2007.11707.x
published as Mon.Not.Roy.Astron.Soc.378:507-524,2007 · Accepted for publication in MNRAS; 21 pages; 25 figures. Four figures are provided separately in reduced jpg format due to their large original ps size: click on "PostScript" to have direct access to the 4 jpg figures; full size ps files for these 4 figures can be found at http://www.aip.de/People/skitsionas/papers/
arxiv created 2007/03/08 · openalex publication_date 2007/05/24 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
We investigate, by means of numerical simulations, the phenomenology of star formation triggered by low-velocity collisions between low-mass molecular clumps. The simulations are performed using a smoothed particle hydrodynamics code which satisfies the Jeans condition by invoking on-the-fly particle splitting. Clumps are modelled as stable truncated (non-singular) isothermal, i.e. Bonnor–Ebert, spheres. Collisions are characterized by M0 (clump mass), b (offset parameter, i.e. ratio of impact parameter to clump radius) and (Mach number, i.e. ratio of collision velocity to effective post-shock sound speed). The gas subscribes to a barotropic equation of state, which is intended to capture (i) the scaling of pre-collision internal velocity dispersion with clump mass, (ii) post-shock radiative cooling and (iii) adiabatic heating in optically thick protostellar fragments. The efficiency of star formation is found to vary between 10 and 30 per cent in the different collisions studied and it appears to increase with decreasing M0, and/or decreasing b, and/or increasing . For b < 0.5 collisions produce shock-compressed layers which fragment into filaments. Protostellar objects then condense out of the filaments and accrete from them. The resulting accretion rates are high, , for the first . The densities in the filaments, , are sufficient that they could be mapped in NH3 or CS line radiation, in nearby star formation regions.