Stability of Filaments in Star-Forming Clouds and the Formation of Prestellar Cores in Them

Anathpindika, S and Freundlich, J (2015) Stability of Filaments in Star-Forming Clouds and the Formation of Prestellar Cores in Them. In: PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF AUSTRALIA, 32 .

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Abstract

The exact process(es) that generate(s) dense filaments which then form prestellar cores within them is unclear. Here we study the formation of a dense filament using a relatively simple set-up of a pressure-confined, uniform-density cylinder. We examine if its propensity to form a dense filament and further, to the formation of prestellar cores along this filament, bears on the gravitational state of the initial volume of gas. We report a radial collapse leading to the formation of a dense filamentary cloud is likely when the initial volume of gas is at least critically stable (characterised by the approximate equality between the mass line-density for this volume and its maximum value). Though self-gravitating, this volume of gas, however, is not seen to be in free-fall. This post-collapse filament then fragments along its length due to the growth of a Jeans-like instability to form prestellar cores. We suggest dense filaments in typical star-forming clouds classified as gravitationally super-critical under the assumption of: (i) isothermality when in fact, they are not, and (ii) extended radial profiles as against pressure-truncated, that significantly over-estimates their mass line-density, are unlikely to experience gravitational free-fall. The radial density and temperature profile derived for this post-collapse filament is consistent with that deduced for typical filamentary clouds mapped in recent surveys of nearby star-forming regions.

Item Type:	Journal Article
Publication:	PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF AUSTRALIA
Publisher:	CAMBRIDGE UNIV PRESS
Additional Information:	Copy right for this article belongs to the CAMBRIDGE UNIV PRESS, 32 AVENUE OF THE AMERICAS, NEW YORK, NY 10013-2473 USA
Keywords:	gravitation; hydrodynamics; ISM: clouds; ISM: structure; prestellar cores
Department/Centre:	Division of Physical & Mathematical Sciences > Physics
Date Deposited:	22 May 2015 07:46
Last Modified:	22 May 2015 07:46
URI:	http://eprints.iisc.ac.in/id/eprint/51574

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