Volume 588, April 2016
|Number of page(s)||10|
|Section||Interstellar and circumstellar matter|
|Published online||15 March 2016|
Mantle formation, coagulation, and the origin of cloud/core shine
I. Modelling dust scattering and absorption in the infrared
Institut d’Astrophysique Spatiale, CNRS, Univ. Paris-Sud, Université
2 School of Physics and Astronomy, Queen Mary, University of London, 327 Mile End Road, London, E1 4NS, UK
3 Centre de Sciences Nucléaires et de Sciences de la Matière, UMR 8609, CNRS/Université Paris Sud, Université Paris-Saclay, Université Paris Sud, 91405 Orsay, France
Received: 1 October 2015
Accepted: 1 February 2016
Context. The observed cloudshine and coreshine (C-shine) have been explained in terms of grain growth leading to enhanced scattering from clouds in the J, H, and K photometric bands and the Spitzer IRAC 3.6 and 4.5 μm bands.
Aims. Using our global dust-modelling approach THEMIS (The Heterogeneous dust Evolution Model at the IaS), we explore the effects of dust evolution in dense clouds, through aliphatic-rich carbonaceous mantle formation and grain-grain coagulation.
Methods. We model the effects of wide band gap a-C:H mantle formation and the low-level aggregation of diffuse interstellar medium dust in the moderately-extinguished outer regions of molecular clouds.
Results. The formation of wide band gap a-C:H mantles on amorphous silicate and amorphous carbon (a-C) grains leads to a decrease in their absorption cross-sections but no change in their scattering cross-sections at near-infrared wavelengths, resulting in higher albedos.
Conclusions. The evolution of dust, with increasing density and extinction in the diffuse-to-dense molecular cloud transition, through mantle formation and grain aggregation, appears to be a likely explanation for the observed C-shine.
Key words: dust, extinction / ISM: general / evolution
© ESO, 2016
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.