ORCA
Online Research @ Cardiff

The minimum mass for opacity-limited fragmentation in turbulent cloud cores

 Boyd, D.F.A. and Whitworth, Anthony Peter 2005. The minimum mass for opacity-limited fragmentation in turbulent cloud cores. Astronomy & Astrophysics 430 (3) , pp. 1059-1066. 10.1051/0004-6361:20041703

 Preview
PDF - Published Version

Abstract

We present a new analysis of the minimum mass for star formation, based on opacity-limited fragmentation. Our analysis differs from the standard one, which considers hierarchical fragmentation of a 3D medium, and yields $M_{_{\rm MIN}} \sim 0.007\;{\rm to}\;0.010\,M_\odot$ for Population I star formation. Instead we analyse the more realistic situation in which there is one-shot fragmentation of a shock-compressed layer, of the sort which arises in turbulent star-forming clouds. In this situation, $M_{_{\rm MIN}}$ can be smaller than $0.003~ M_\odot$. Our analysis is more stringent than the standard one in that (a) it requires fragments to have condensation timescales shorter than all competing mass scales, and (b) it takes into acount that a fragment grows by accretion whilst it is condensing out, and therefore has to radiate away the energy dissipated in the associated accretion shock (in addition to the Pd V work done by internal compression). It also accords with the recent detection, in young star clusters, of free-floating star-like objects having masses as low as $0.003\,{M}_\odot$.

Item Type: Article Publication Published Physics and Astronomy Q Science > QB Astronomy stars: formation; ISM: clouds; turbulence; hydrodynamics Pdf uploaded in accordance with publisher's policy at http://www.sherpa.ac.uk/romeo/issn/0004-6361/ (accessed 16/04/2014) EDP Sciences 0004-6361 30 March 2016 04 Jun 2017 04:58 http://orca.cf.ac.uk/id/eprint/47045