2006/07/03 by Paolo Padoan, Laurent Cambresy, Mika Juvela +3 · 5 citations
Physics and Astronomy · #Amplitude #Astrophysics and Star Formation Studies #Extinction (optical mineralogy) #Galaxies: Formation, Evolution, Phenomena #Molecular cloud #Observable #Optical properties and cooling technologies in crystalline materials #Range (aeronautics) #Supersonic speed #Turbulence #astro-ph
paper · pdf · doi:10.1086/507068
published as Astrophys.J.649:807-815,2006 · 10 pages, 8 figures included, ApJ, in press
arxiv created 2006/07/03 · openalex publication_date 2006/09/27 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
Maps of estimated dust column density in molecular clouds are usually assumed to reliably trace the total gas column density structure. In this work we present results showing a clear discrepancy between the dust and the gas distribution in the Taurus molecular cloud complex. We compute the power spectrum of a 2MASS extinction map of the Taurus region and find that it is much shallower than the power spectrum of a 13 CO map of the same region that was previously analyzed. This discrepancy could be explained as the effect of grain growth on the grain extinction efficiency. However, this would require a wide range of maximum grain sizes, which is ruled out based on constraints from the extinction curve and the available grain models. We show that major effects due to CO formation and depletion are also ruled out. Our result may therefore suggest the existence of intrinsic spatial fluctuations of the dust-to-gas ratio, with amplitude increasing toward smaller scales. Preliminary results of numerical simulations of trajectories of inertial particles in turbulent flows illustrate how the process of clustering of dust grains by the cloud turbulence may lead to observable effects. However, these results cannot be directly applied to large-scale supersonic and magnetized turbulence at present.