Query : 2006A&A...451..141H

2006A&A...451..141H - Astronomy and Astrophysics, volume 451, 141-146 (2006/5-3)

A dynamical model for the dusty ring in the Coalsack.


Abstract (from CDS):

Lada et al. recently presented a detailed near-infrared extinction map of Globule G2 in the Coalsack molecular cloud complex, showing that this starless core has a well-defined central extinction minimum. We propose a model for G2 in which a rapid increase in external pressure is driving an approximately symmetric compression wave into the core. The rapid increase in external pressure could arise because the core has recently been assimilated by the Coalsack cloud complex, or because the Coalsack has recently been created by two large-scale converging flows. The resulting compression wave has not yet converged on the centre of the core, so there is a central rarefaction. The compression wave has increased the density in the swept-up gas by about a factor of ten, and accelerated it inwards to speeds of order 0.4km/s. It is shown that even a low initial level of turbulence completely destroys the coherence of the ring, as seen in projection. In the scenario of strong external compression that we are proposing this implies that the initial turbulent energy in the globule was low, ETURB/|EGRAV|≤2%. Protostar formation should occur in about 40000-years.

Abstract Copyright:

Journal keyword(s): ISM: clouds - stars: formation - hydrodynamics - instabilities - shock waves

Simbad objects: 5

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Number of rows : 5
N Identifier Otype ICRS (J2000)
ICRS (J2000)
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
1 NAME Coalsack Nebula DNe 12 31 19 -63 44.6           ~ 256 0
2 NAME Coalsack G2 MoC 12 31 29 -63 44.8           ~ 40 0
3 GN 12.54.3 RNe 12 57 23 -61 31.6           ~ 9 0
4 LDN 57 DNe 17 22 38.2 -23 49 34           ~ 309 1
5 LDN 663 DNe 19 36 55 +07 34.4           ~ 625 0

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