Context. Ionising stars reshape their original molecular cloud and impact star formation, leading to spectacular morphologies such as bipolar nebulae around H ii regions. Molecular clouds are structured in filaments where stars principally form, as revealed by the Herschel space observatory. The prominent southern hemisphere H ii region, RCW 36, is one of these bipolar nebulae. Aims. We study t...

We have constructed three-dimensional models for the equilibrium abundance of molecular hydrogen within diffuse interstellar clouds of arbitrary geometry that are illuminated by ultraviolet radiation. The position-dependent photodissociation rate of H2 within such clouds was computed using a 26-ray approximation to model the attenuation of the incident ultraviolet radiation field by dust and by...

We report the first detection of a chlorine-bearing molecular species in the interstellar medium via emission from the J = 1----> 0 transition of HCl at 625.9 GHz toward OMC-1. The relative strengths, widths, and velocities of the resolved hyperfine components are consistent with moderate optical depth emission originating from dense, quiescent molecular cloud material (VLsR = 9 km s1). The ove...

At present, the heliosphere is embedded in a warm low density interstellar cloud that belongs to a cloud system flowing through the local standard of rest with a velocity near ∼18 km s. The velocity structure of the nearest interstellar material (ISM), combined with theoretical models of the local interstellar cloud (LIC), suggest that the Sun passes through cloudlets on timescales of ≤ 10–10 y...

We have studied optical properties of interstellar dust around the Orion A molecular cloud to investigate size distribution and composition grains. is one most clouds in solar vicinity ($d \simeq 400\ \rm{pc}$). In this paper, we used near-infrared photometric data. The data were obtained by $BVRI$ bands imaging observations. consisting $JHK_{S}$ taken from 2MASS point source catalog. produced ...

Several nearby individual low column density interstellar cloudlets have been identified previously based on kinematical features evident in high-resolution Ca observations near the Sun. One of these cloudlets, the ‘Apex Cloud” (AC), is within 5 pc of the Sun in the solar apex direction. The question of which interstellar cloud will constitute the next galactic environment of the Sun in princip...

It is believed that the observed diffuse gamma ray emission from the galactic plane is the result of interactions between cosmic rays and the interstellar gas. Such emission can be amplified if cosmic rays penetrate into dense molecular clouds. The propagation of cosmic rays inside a molecular cloud has been studied assuming an arbitrary energy and space dependent diffusion coefficient. If the ...

We propose a new method to constrain the actual state of the interstellar cloud that surrounds the solar system. Using Voyager UVS Lyman-α sky maps and the powerful principle of invariance, we derive the H distribution all along the spacecraft path. Provided current models of the heliopause interface between the solar and the interstellar winds, we extrapolate this distribution to farther dista...

We investigate interstellar absorption from molecular hydrogen (H2) and metals in an intermediatevelocity cloud (IVC) in the direction of the LMC star Sk -68 80 (HD36521), based on data from the Far Ultraviolet Spectroscopic Explorer (FUSE) satellite. H2 absorption from the Lymanand Werner bands is detected in 30 lines at radial velocities vLSR ≈ +50 km s −1 in this IVC that is presumably locat...