相关论文: Grain Destruction in Interstellar Shocks
Some very large (>0.1 um) presolar grains are sampled in meteorites. We reconsider the lifetime of very large grains (VLGs) in the interstellar medium focusing on interstellar shattering caused by turbulence-induced large velocity…
We calculate the relative grain-grain motions arising from interstellar magnetohydrodynamic (MHD) turbulence. The MHD turbulence includes both fluid motions and magnetic fluctuations. While the fluid motions accelerate grains through…
By using the flux ratio [FeII]8617/[OI]6300, we demonstrate that most of the interstellar dust grains survive in shocks associated with supernova remnants and Herbig-Haro objects. The [FeII]/[OI] flux ratio is sensitive to the gas-phase…
Scattering and absorption of X-rays by interstellar dust is calculated for a model consisting of carbonaceous grains and amorphous silicate grains. The calculations employ realistic dielectric functions with structure near X-ray absorption…
Observed reddening in the circum-galactic medium (CGM) indicates a significant abundance of small grains, of which the origin is still to be clarified. We examine a possible path of small-grain production through shattering of pre-existing…
We put theoretical constraints on the presence and survival of icy grains in debris discs. Particular attention is paid to UV sputtering of water ice, which has so far not been studied in detail in this context. We present a photosputtering…
Our current understanding of interstellar dust is summarized at an introductory level. Submicron-sized interstellar dust grains absorb and scatter light, and reradiate the absorbed energy in the infrared. The grain population spans a range…
The feedback from massive stars drives the evolution of interstellar dust grains by altering their physical properties via a number of radiative and mechanical processes. Through these interactions, interstellar grains can achieve high…
Supernova ejecta and stellar winds are believed to produce interstellar dust grains with relatively large sizes. Smaller grains can be produced via the shattering of large grains that have been stochastically accelerated. To understand this…
We investigate the evolution of grains composed of an ice shell surrounding an olivine core as they pass through a spiral shock in a protoplanetary disk. We use published three-dimensional radiation-hydrodynamics simulations of massive…
The properties of interstellar grains, such as grain size distribution and grain porosity, are affected by interstellar processing, in particular, coagulation and shattering, which take place in the dense and diffuse interstellar medium…
We investigate the role and behaviour of dust grains in C-type MHD shock waves in weakly ionized, dense molecular clouds. New shock models are presented for steady, oblique C-type shock structures with shock speed v_s=18km/s, n_H=10^5cm^-3,…
The origin of grain size distribution in the interstellar medium is one of the most fundamental problems in the interstellar physics. In the Milky Way, smaller grains are more abundant in number, but their origins are not necessarily…
We present the first results for the sputtering of grain mantles and cores obtained with self-consistent multifluid hydromagnetic models of C-type shocks propagating through dusty media. The threshold shock speed for mantle sputtering is…
We present evolutionary calculations for the size and aromatization degree distributions of interstellar dust grains, driven by their destruction by radiation, collisions with gas particles, and shattering due to grain-grain collisions.…
In protoplanetary discs, the coagulation of dust grains into large aggregates still remains poorly understood. Grain porosity appears to be a promising solution to allow the grains to survive and form planetesimals. Furthermore, dust…
Dust grains may be accelerated to relativistic speeds by radiation pressure, diffusive shocks, and other acceleration mechanisms. Such relativistic grains have been suggested as primary particles of ultrahigh energy cosmic rays (UHECRs). In…
The sizes of interstellar grains are widely distributed, ranging from a few angstroms to a few micrometers. The ultraviolet (UV) and optical extinction constrains the dust in the size range of a couple hundredth micrometers to several…
Observations of interstellar extinction and polarization indicate that the interstellar medium consists of aligned non-spherical dust grains which show variation in the interstellar extinction curve for wavelengths ranging from NIR to UV.…
The composite grain is made up of a host silicate spheroid and graphite inclusions. The extinction efficiencies of the composite spheroidal grains for three axial ratios are computed using the discrete dipole approximation (DDA). The…