diffuse interstellar cloud
abr-e andaraxtari-ye paxšidé
Fr.: nuage interstellaire diffus
An → interstellar cloud in which hydrogen is completely dissociated and which is less dense and dusty than → molecular clouds. In diffuse interstellar clouds photoabsorption of the background → ultraviolet (UV) radiation field is an important dissociating and ionizing process. Typical densities and temperatures of diffuse clouds are 102 to 103 cm-3 and 20 to 100 K respectively. Because of modest extinctions (≤ 1 mag), → photodissociation processes are important in diffuse clouds preventing the formation of larger molecules.
Fr.: nuage interstellaire
An aggregation of gas and dust in the → interstellar medium containing large quantities of atoms, molecules, and dust. There are several types of interstellar clouds, such as → diffuse interstellar clouds, → dark clouds, → molecular clouds.
local interstellar cloud
abr-e andar-axtari-ye mahali
Fr.: nuage interstellaire local