C.D.S. - SIMBAD4 rel 1.7 - 2021.04.19CEST13:52:21

2008ApJ...682.1095B - Astrophys. J., 682, 1095-1102 (2008/August-1)

The damping rates of embedded oscillating starless cores.


Abstract (from CDS):

In a previous paper we demonstrated that nonradial hydrodynamic oscillations of a thermally supported (Bonnor-Ebert) sphere embedded in a low-density, high-temperature medium persist for many periods. The predicted column density variations and molecular spectral line profiles are similar to those observed in the Bok globule B68, suggesting that the motions in some starless cores may be oscillating perturbations on a thermally supported equilibrium structure. Such oscillations can produce molecular line maps which mimic rotation, collapse, or expansion and, thus, could make determining the dynamical state from such observations alone difficult. However, while B68 is embedded in a very hot, low-density medium, many starless cores are not, having interior/exterior density contrasts closer to unity. In this paper we investigate the oscillation damping rate as a function of the exterior density. For concreteness we use the same interior model employed by Broderick et al., with varying models for the exterior gas. We also develop a simple analytical formalism, based on the linear perturbation analysis of the oscillations, which predicts the contribution to the damping rates due to the excitation of sound waves in the external medium. We find that the damping rate of oscillations on globules in dense molecular environments is always many periods, corresponding to hundreds of thousands of years and persisting over the inferred lifetimes of the globules.

Abstract Copyright:

Journal keyword(s): Hydrodynamics - ISM: Clouds - ISM: Globules - Stars: Formation

Simbad objects: 6

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Number of rows : 6

N Identifier Otype ICRS (J2000)
ICRS (J2000)
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2021
1 NAME Perseus Cloud SFR 03 35.0 +31 13           ~ 1131 0
2 NAME Taurus Complex SFR 04 41.0 +25 52           ~ 3681 0
3 LDN 1544 DNe 05 04 16.6 +25 10 48           ~ 725 0
4 NAME [BM89] L1544 cor 05 04 22.5 +25 11 36           ~ 435 1
5 LDN 57 DNe 17 22 38.2 -23 49 34           ~ 286 1
6 NAME the Pipe Nebula DNe 17 30 -25.0           ~ 351 1

    Equat.    Gal    SGal    Ecl

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