Interstellar gases are gaseous substances composed of molecules.Interstellar gas is generally neutral and can only be ionized near thermal giant and supergiant.The first evidence for the existence of gas between stars E was German astronomers in 1904Hartmann(Johannes Hartmann) found on the spectrum of Orion S that a calcium absorption line did not produce any movement, indicating that the calcium vapor does not move with the star. The gas of this absorption line has nothing to do with the star, but is distributed in the interstellar space between the sun and the "Mintaka" star.Later, absorption lines of many other elements were found in interstellar gas.The composition of this gas is generally similar to that of star family I, and the main component is hydrogen. A small amount of other elements may be released by supernova explosion. Some elements seem rare but can be found in interstellar dust.
Interstellar gases are mainlyhydrogen, followed byheliumMost wave bands of electromagnetic radiation are basically transparent, and can be observed mostly through radio waves.About 10% of the Milky Way's mass is gaseous.[1]
stayuniverseMiddle, when thedensityTo a certain extent, due to the internalgravitationIt increases faster than the gas pressureGas cloudAnd began to shrink.At the beginning of this trend, its own gravity will promote the density of a large amount of matter to rise at the same time.At the same time, the stellar matter with astonishing mass becomes unstable.These huge amounts of interstellar gas and dustCollapseMore and more rapidly, some gases form smaller clouds, and their density increases respectively.These smaller clouds later became onefixed star。
