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Related papers: Grains in Photo-Ionized Environments

200 papers

The ionization and thermal state of the intergalactic medium (IGM) during the epoch of reionization has been of interest in recent times because of their close connection to the first stars. We present in this paper a semi-numerical code…

Cosmology and Nongalactic Astrophysics · Physics 2022-01-26 Barun Maity , Tirthankar Roy Choudhury

Grains exposed to anisotropic radiation fields are subjected to forces due to the asymmetric photon-stimulated ejection of particles. These forces act in addition to the ``radiation pressure'' due to absorption and scattering. Here we model…

Astrophysics · Physics 2009-10-31 Joseph C. Weingartner , B. T. Draine

Computational models of interstellar gas-grain chemistry have historically adopted a single dust-grain size of 0.1 micron, assumed to be representative of the size distribution present in the interstellar medium. Here, we investigate the…

Astrophysics of Galaxies · Physics 2016-02-03 Tyler Pauly , Robin T. Garrod

Mineral clouds in substellar atmospheres play a special role as a catalyst for a variety of charge processes. If clouds are charged, the surrounding environment becomes electrically activated, and ensembles of charged grains are…

Earth and Planetary Astrophysics · Physics 2015-06-18 R. L. Bailey , Ch. Helling , G. Hodosán , C. Bilger , C. R. Stark

Theoretical models of compaction processes, such as for example intergranular pressure-solution (IPS), focus on deformation occurring at the contacts between spherical grains that constitute an aggregate. In order to investigate the…

Geophysics · Physics 2008-01-04 Magali Rossi , Olivier Vidal , Bernd Wunder , François Renard

It is well known that the polarized continuum emission from magnetically aligned dust grains is determined to a large extent by local magnetic field structure. However, the observed significant anticorrelation between polarization fraction…

Astrophysics of Galaxies · Physics 2019-10-02 Patrick K. King , Che-Yu Chen , Laura M. Fissel , Zhi-Yun Li

Clouds have a significant impact on the Earth's climate system. They play a vital role in modulating Earth's radiation budget and driving regional changes in temperature and precipitation. This makes clouds ideal for climate intervention…

Coarse-grained models are a core computational tool in theoretical chemistry and biophysics. A judicious choice of a coarse-grained model can yield physical insight by isolating the essential degrees of freedom that dictate the…

Statistical Mechanics · Physics 2023-04-12 Shriram Chennakesavalu , David J. Toomer , Grant M. Rotskoff

Photoionization models obtained with numerical codes are widely used to study the physics of the interstellar medium (Planetary Nebulae, H II regions, etc). Grid of models are performed to understand what are the effects of the different…

Astrophysics of Galaxies · Physics 2014-12-18 Christophe Morisset , Gloria Delgado-Inglada , Nahiely Flores-Fajardo

Context: Complex molecules such as ethanol and dimethyl ether have been observed in a number of hot molecular cores and hot corinos. Attempts to model the molecular formation process using gas phase only models have so far been…

Astrophysics of Galaxies · Physics 2015-05-18 P. Hall , T. J. Millar

A continuum grain boundary model is developed that uses experimentally measured grain boundary energy data as a function of misorientation to simulate idealized grain boundary evolution in a 1-D grain array. The model uses a continuum…

Materials Science · Physics 2024-01-29 Syed Ansari , Amit Acharya , Alankar Alankar

Interstellar dust grain growth in dense clouds and protoplanetary disks, even moderate, affects the observed interstellar ice profiles as soon as a significant fraction of dust grains is in the size range close to the wave vector at the…

Astrophysics of Galaxies · Physics 2022-10-26 Emmanuel Dartois , Jennifer A. Noble , Nathalie Ysard , Karine Demyk , Marin Chabot

A multi-phase field model is employed to study the microstructural evolution of an alloy undergoing liquid dealloying. The model proposed extends upon the original approach of Geslin et al. to consider dealloying in the presence of grain…

Materials Science · Physics 2023-08-07 Nathan Bieberdorf , Mark D. Asta , Laurent Capolungo

In this contribution we discuss about numerical modeling of nebulae. In particular we emphasize on the dynamical evolution of an HII region and the chemical structure of a Photodissociation region. We do this using the Smoothed Particles…

Solar and Stellar Astrophysics · Physics 2012-08-16 Thomas G. Bisbas

Models of astrophysical dust are key to understand several physical processes, from the role of dust grains as cooling agents in the ISM to their evolution in dense circumstellar disks, explaining the occurrence of planetary systems around…

Astrophysics of Galaxies · Physics 2025-06-18 M. -A. Carpine , N. Ysard , A. Maury , A. Jones

We present a method for modelling star-forming clouds that combines two different models of the thermal evolution of the interstellar medium (ISM). In the combined model, where the densities are low enough that at least some part of the…

Solar and Stellar Astrophysics · Physics 2015-03-19 Matthew R. Bate , Eric R. Keto

We study alignment of grains by radiative torques. We found steep rise of radiative torque efficiency as grain size increases. This allows larger grains that are known to exist within molecular clouds to be aligned by the attenuated and…

Astrophysics · Physics 2009-11-11 J. Cho , A. Lazarian

We present a study of the elemental depletion in the interstellar medium. We combined the results of a Galatic model describing the gas physical conditions during the formation of dense cores with a full-gas-grain chemical model. During the…

Astrophysics of Galaxies · Physics 2020-07-29 V. Wakelam , W. Iqbal , J. -P. Melisse , P. Gratier , M. Ruaud , I. Bonnell

An elementary model is developed for grain growth during the expansion stage of nova ejecta. Rather than suppressing grain formation, we argue that agglomeration of atoms by dust nuclei proceeds kinetically through induced dipole reactions…

Astrophysics · Physics 2009-11-10 Steven N. Shore , R. D. Gehrz

We present the implementation of dusty, radiation pressure dominated photoionization models applicable to the Narrow Line Regions (NLRs) of Active Galactic Nuclei, using the \mapiii code. We give a grid of the predicted intensities of the…

Astrophysics · Physics 2009-11-10 Brent A. Groves , Michael A. Dopita , Ralph S. Sutherland