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Related papers: Grains in Photo-Ionized Environments

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Context. The contribution of quiet-Sun regions to the solar irradiance variability is currently unclear. Some solar-cycle variations of the quiet-Sun physical structure, such as the temperature gradient, might affect the irradiance. The…

Solar and Stellar Astrophysics · Physics 2018-09-05 M. Faurobert , M. Carbillet , L. Marquis , A. Chiavassa , G. Ricort

Aligned non-spherical dust particles polarize starlight passing through the dust cloud. They also emit polarized far infrared and sub-mm radiation. Substantial progress in understanding of grain alignment theory makes the interpretation of…

Astrophysics · Physics 2007-05-23 A. Lazarian

Cosmic dust particles effectively attenuate starlight. Their absorption of starlight produces emission spectra from the near- to far-infrared, which depends on the sizes and properties of the dust grains, and spectrum of the heating…

Instrumentation and Methods for Astrophysics · Physics 2013-11-20 Troy A. Porter , Andrey E. Vladimirov

A model of key processes influencing the evolution of a hydrocarbon grain of an arbitrary size under astrophysical conditions corresponding to ionized hydrogen regions (HII regions) and supernova remnants is presented. The considered…

Astrophysics of Galaxies · Physics 2016-12-07 M. S. Murga , S. A. Khoperskov , D. S. Wiebe

The origin of the grains with diameters less than 4 micron from the inclusions in Antarctic ice cores is discussed. It is proposed that these grains were initiated by ions stopped in the upper atmosphere. The ions form molecules, which…

Geophysics · Physics 2009-09-29 W. Baltensperger , W. Woelfli

Whether ice in cold cosmic environments is physically separated from the silicate dust or mixed with individual silicate moieties is not known. However, different grain models give very different compositions and temperatures of grains. The…

Astrophysics of Galaxies · Physics 2020-08-26 Alexey Potapov , Jeroen Bouwman , Cornelia Jäger , Thomas Henning

Materials containing a high proportion of grain boundaries offer significant potential for the development of radiation-resistent structural materials. However, a proper understanding of the connection between the radiation-induced…

Materials Science · Physics 2018-07-04 Yichao Zhu , Jing Luo , Xu Guo , Yang Xiang , Stephen Jonathan Chapman

We present high resolution ($1024^3$) simulations of super-/hyper-sonic isothermal hydrodynamic turbulence inside an interstellar molecular cloud (resolving scales of typically 20 -- 100 AU), including a multi-disperse population of dust…

Astrophysics of Galaxies · Physics 2018-12-19 Lars Mattsson , Akshay Bhatnagar , Fred A. Gent , Beatriz Villarroel

The Intergalactic Medium (IGM) contains $>$50% of the baryonic mass of the Universe, yet the mechanisms responsible for keeping the IGM ionized has not been fully explained. Hence, we investigate ion abundances from the largest blind QSO…

Cosmology and Nongalactic Astrophysics · Physics 2024-03-04 Brad Koplitz , Anjali Ramesh , Sanchayeeta Borthakur

Surface processes on cosmic solids in cold astrophysical environments lead to gas phase depletion and molecular complexity. Most astrophysical models assume that the molecular ice forms a thick multilayer substrate, not interacting with the…

Astrophysics of Galaxies · Physics 2020-06-17 Alexey Potapov , Cornelia Jäger , Thomas Henning

We survey the current situation regarding chemical modelling of the synthesis of molecules in the interstellar medium. The present state of knowledge concerning the rate coefficients and their uncertainties for the major gas-phase processes…

Aerosol particles play an important role in the climate system by absorbing and scattering radiation and influencing cloud properties. They are also one of the biggest sources of uncertainty for climate modeling. Many climate models do not…

Machine Learning · Computer Science 2022-07-26 Paula Harder , Duncan Watson-Parris , Philip Stier , Dominik Strassel , Nicolas R. Gauger , Janis Keuper

The binding energies (BE) of molecules on the interstellar grains are crucial in the chemical evolution of the interstellar medium (ISM). Both temperature programmed desorption (TPD) laboratory experiments and quantum chemistry computations…

Astrophysics of Galaxies · Physics 2022-05-25 Lorenzo Tinacci , Aurele Germain , Stefano Pantaleone , Stefano Ferrero , Cecilia Ceccarelli , Piero Ugliengo

A quantitative analysis of grain alignment in the filamentary dark cloud L1755 in Ophiuchus is presented. We show, that the observed decrease of the polarization to extinction ratio for the inner parts of this quiescent dark cloud can be…

Astrophysics · Physics 2008-11-26 A. Lazarian , Alyssa A. Goodman , Philip C. Myers

High-shear methods have long been used in experiments to refine grain structures in metals, yet the underlying mechanisms remain elusive. We demonstrate a refinement process using molecular dynamic simulations of iron, wherein…

Materials Science · Physics 2025-05-29 Ivan Tolkachev , Pui-Wai Ma , Daniel Mason , Felix Hofmann

A simple numerical model which calculates the kinetics of crystallization involving randomly distributed nucleation and isotropic growth is presented. The model can be applied to different thermal histories and no restrictions are imposed…

Materials Science · Physics 2008-11-17 J. Farjas , P. Roura

We revisit the evolution model of grain size distribution in a galaxy for the ultimate purpose of implementing it in hydrodynamical simulations. We simplify the previous model in such a way that some model-dependent assumptions are replaced…

Astrophysics of Galaxies · Physics 2018-10-31 Hiroyuki Hirashita , Shohei Aoyama

A simple model for the solidification of globular grains in metallic alloys is presented. Based on the Voronoi diagram of the nuclei centers, it accounts for the curvature of the grains near triple junctions. The predictions of this model…

Materials Science · Physics 2007-11-28 Stéphane Vernède , Michel Rappaz

Polarization of optical starlight and far-infrared thermal dust emission due to alignment of interstellar grains offers a powerful window to study magnetic fields in the various astrophysical environments, from the diffuse interstellar…

Astrophysics of Galaxies · Physics 2017-04-07 Thiem Hoang

Stochastic heating of small grains is often mentioned as a primary cause of large infrared (IR) fluxes from star-forming galaxies, e.g. at 24\mu m. If the mechanism does work at a galaxy-wide scale, it should show up at smaller scales as…

Astrophysics of Galaxies · Physics 2015-06-03 Ya. N. Pavlyuchenkov , D. S. Wiebe , V. V. Akimkin , M. S. Khramtsova , Th. Henning
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