High-resolution simulations of clump-clump collisions using SPH with particle splitting

Kitsionas, S. and Whitworth, Anthony Peter ORCID: https://orcid.org/0000-0002-1178-5486 2007. High-resolution simulations of clump-clump collisions using SPH with particle splitting. Monthly Notices of the Royal Astronomical Society 378 (2) , pp. 507-524. 10.1111/j.1365-2966.2007.11707.x

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Abstract

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 Graphic (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 Graphic. 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, Graphic, for the first Graphic. The densities in the filaments, Graphic, are sufficient that they could be mapped in NH3 or CS line radiation, in nearby star formation regions.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Physics and Astronomy
Subjects:	Q Science > QB Astronomy
Uncontrolled Keywords:	accretion, accretion discs ; hydrodynamics ; methods: numerical ; binaries:general ; stars:formation ; ISM:clouds
Publisher:	Oxford University Press
ISSN:	0035-8711
Last Modified:	24 Oct 2022 10:54
URI:	https://orca.cardiff.ac.uk/id/eprint/46341

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