Cosmic dust - Introductory Material

Cosmic dust - Introductory Material. Cosmic Dust refers to particles in space which are assemblages of a few molecules to tenth-millimeter-sized grains. Cosmic dust can be further distinguished by its astronomical location; for example: interplanetary dust, interstellar dust, comet dust, circumplanetary dust. This article covers bulk and radiative properties of cosmic dust, the dust particles' origins, end-fates, and specific locations in space. Historically, cosmic dust used to be an annoyanc ...

Including:

• Cosmic dust - Introductory Material
• Cosmic dust - Some bulk properties of cosmic dust
• Cosmic dust - Radiative properties of cosmic dust
• Cosmic dust - Dust grain formation
• Cosmic dust - Dust grain destruction
• Cosmic dust - Some dusty clouds in the universe

Read more here: » Cosmic dust: Encyclopedia - Cosmic dust

Cosmic Dust refers to particles in space which are assemblages of a few molecules to tenth-millimeter-sized grains. Cosmic dust can be further distinguished by its astronomical location; for example: interplanetary dust, interstellar dust, comet dust, circumplanetary dust. This article covers bulk and radiative properties of cosmic dust, the dust particles' origins, end-fates, and specific locations in space. Historically, cosmic dust used to be an annoyance to astronomers because of the way that the dust obscures the object th ...

See also:

Cosmic dust, Cosmic dust - Introductory Material, Cosmic dust - Some bulk properties of cosmic dust, Cosmic dust - Radiative properties of cosmic dust, Cosmic dust - Dust grain formation, Cosmic dust - Dust grain destruction, Cosmic dust - Some dusty clouds in the universe

Read more here: » Cosmic dust: Encyclopedia II - Cosmic dust - Introductory Material

How are the interstellar grains destroyed? There are some ultraviolet processes which lead to grain "explosions" (d'Hendecourt et al., 1985; Greenberg, 1976). Evans (1994) also describes evaporation, sputtering (when an atom or ion strikes the surface of a solid with enough momentum to eject atoms from it), and grain-grain collisions, which have a major influence on the grain size distribution, as well. These destructive processes happen in a variety of places. Some grains are destroyed in the supernovae/novae explosion (and then some ...

See also:

Cosmic dust, Cosmic dust - Introductory Material, Cosmic dust - Some bulk properties of cosmic dust, Cosmic dust - Radiative properties of cosmic dust, Cosmic dust - Dust grain formation, Cosmic dust - Dust grain destruction, Cosmic dust - Some dusty clouds in the universe

Read more here: » Cosmic dust: Encyclopedia II - Cosmic dust - Dust grain destruction

A dust particle interacts with electromagnetic radiation in a way that depends on its cross section, the wavelength of the electromagnetic radiation, and on the nature of the grain: its refractive index, size, etc. The radiation process for an individual grain is called its emissivity, dependent on the grain's efficiency factor. Furthermore, we have to specify whether the emissivity process is extinction, scattering, or absorption. In the radiation emission curves, several important signatures id ...

See also:

Cosmic dust, Cosmic dust - Introductory Material, Cosmic dust - Some bulk properties of cosmic dust, Cosmic dust - Radiative properties of cosmic dust, Cosmic dust - Dust grain formation, Cosmic dust - Dust grain destruction, Cosmic dust - Some dusty clouds in the universe

Read more here: » Cosmic dust: Encyclopedia II - Cosmic dust - Radiative properties of cosmic dust

Cosmic dust is dust grains and agreggates of dust grains. These particles are irregularly-shaped with porosity ranging from fluffy to compact. The composition, size, and other properties depends on where the dust is found. General diffuse interstellar medium dust should be distinguished from dust grains in dense clouds, which should be distinguished from planetary rings dust, which should be distinguished from circumstellar dust, and so on. For example, grains in dense clouds have acquired a mantle of ice and the average dimens ...

See also:

Cosmic dust, Cosmic dust - Introductory Material, Cosmic dust - Some bulk properties of cosmic dust, Cosmic dust - Radiative properties of cosmic dust, Cosmic dust - Dust grain formation, Cosmic dust - Dust grain destruction, Cosmic dust - Some dusty clouds in the universe

Read more here: » Cosmic dust: Encyclopedia II - Cosmic dust - Some bulk properties of cosmic dust

The large grains start with the silicate particles forming in the atmospheres of cool stars, and carbon grains in the atmospheres of cool carbon stars. Stars, which have evolved off the main sequence, and which have entered the giant phase of their evolution, are a major source of dust grains in galaxies. How do astronomers know that that dust is formed in the envelopes of late-evolved stars? They know from their observations. An observed (infrared) 9.7 micrometre emission silicate signature for cool evolved (oxygen-rich giant) stars. ...

See also:

Cosmic dust, Cosmic dust - Introductory Material, Cosmic dust - Some bulk properties of cosmic dust, Cosmic dust - Radiative properties of cosmic dust, Cosmic dust - Dust grain formation, Cosmic dust - Dust grain destruction, Cosmic dust - Some dusty clouds in the universe

Read more here: » Cosmic dust: Encyclopedia II - Cosmic dust - Dust grain formation