Interstellar cloud
An interstellar cloud is a denser-than-average part of the interstellar medium, (ISM). It is matter and radiation in the space between the star systems in a galaxy.
A small part of the emission nebula NGC 6357. It glows with the characteristic red of an H II region.[1]
An interstellar cloud is formed by the gas and dust particles from a red giant in its later life.
The cloud is made of gas, plasma, and dust in our and other galaxies.
Its hydrogen can be:
- neutral, making it an H I region;
- ionized, or plasma making it an H II region; or
- molecular (molecular clouds).
Neutral and ionized clouds are sometimes also called diffuse clouds.
Sources
- "Carved by Massive Stars". ESO Picture of the Week. European Southern Observatory. Retrieved 13 September 2013.
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