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A cloud of ionized gas emitting light of various colors. These nebulae are often the site of star formation, particularly when they are associated with giant molecular clouds.

Dense dust clouds that reflect the light of nearby or embedded stars. They do not emit their own light but may be associated with star-forming regions, often seen around young stars that are still in the process of gathering mass.

A type of interstellar cloud that is so dense that it obscures the light from objects behind it. These are often sites of future star formation, as they contain the cool molecular hydrogen and dust needed to form new stars.

A shell of ionized gas ejected from red giant stars at the end of their lives. They play an important role in enriching the interstellar medium with heavy elements and can spark the formation of new stars through shock waves they send through their surroundings.

The coldest and densest type of interstellar cloud, mainly composed of hydrogen molecules. They are the stellar nurseries of the galaxy, where stars are born from the collapse of regions within the cloud under their own gravity.