The method for the extinction correction based on the gas column density is tested. A positive correlation is found between the total gas column density and the extinction estimated using amodel based on energy conservation (‘frequencyconverter model’). Assuming a Solar Neighbourhood opticaldepth–to–gas ratio, extinction is predicted from the gas column density using a radiative transfer model ...

The head-on collision between two dust-acoustic solitary waves in an unmagnetized dusty plasma is investigated, including consideration of the dust charge variation. By using the extended Poincaré-Lighthill-Kuo perturbation method, the analytical phase shifts following the head-on collision are derived. The effects of the ratio of ion temperature to electron temperature, the ratio of the number...

The ion-acoustic instability in a dusty negative ion plasma is investigated, focusing on the parameter regime in which the negative ion density is much larger than the electron density. The dynamics of the massive dust grains are neglected, but collisions of electrons and ions with dust grains in addition to other collisional processes are taken into account. The presence of a population of cha...

Comet 67P/Churyumov-Gerasimenko (67P hereinafter) is characterised by a dust transfer from the southern hemi-nucleus to the night-side northern dust deposits, which constrains the dust-to-ices mass ratio inside the nucleus to values a factor two larger than that provided by the lost mass of gas and non-volatiles. This applies to all comets, because the gas density in all night comae cannot prev...

The aim of this study is to determine the area affected by dust storms in different wind speeds using satelliteimages. In the first step, windy conditions of the Sistan plain were analyzed using wind statistics data. Next, fivestormy days of Zabol city, indicating different wind speeds and horizontal visibilities during those storms, wereselected. Then, high temporal resolution MODIS data was u...

The presence of the two distinct groups of ultracool dwarfs (UCDs), ‘L’ and ‘T’ types, is now well established: L dwarfs are thought to be dusty while T dwarfs show strong bands of methane (CH4) but little evidence for dust in their spectra. So far, different model sequences, which we referred to as the dusty model (or case B) and dustsegregated model (or case C) have been considered for L and ...

When helicopters operate close to the ground in desert conditions, the rotor wake can entrain large amounts of dust into the flow field surrounding the aircraft. This entrainment of dust can result in the potentially dangerous condition known as brownout where the pilot loses situational awareness. Understanding the physics that governs the entrainment of dust from the ground may eventually all...

The presence of the two distinct groups of ultracool dwarfs (UCDs), ‘L’ and ‘T’ types, is now well established: L dwarfs are thought to be dusty while T dwarfs show strong bands of methane (CH4) but little evidence for dust in their spectra. So far, different model sequences, which we referred to as the dusty model (or case B) and dustsegregated model (or case C) have been considered for L and ...

Charging mechanism of dust particles in a nonuniform discharge plasma under cryogenic environment is studied theoretically. The plasma density and temperature effects on dust grain charging are investigated with characteristic time scales of density variation and temperature relaxation in consideration. The charge of a dust grain, initially placed in a discharge plasma and cooled to cryogenic t...