HII stands for "ionized hydrogen" and refers to a region around a hot star where the intense radiation causes the hydrogen atoms to lose their electrons and become ionized (HII). This ionized gas emits light at specific wavelengths, which can be observed with telescopes.

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An HII Region Is

Question 6

Multiple Choice

An HII region is

A) a zone around a hot star where hydrogen atoms are ionized
B) a place where there is mostly neutral hydrogen whose spectral lines we observe
C) a cloud of dark dust, which absorbs much of the starlight coming from behind it
D) one of the large and cold molecular clouds where we see star formation going on
E) a cloud of complex molecules, such as alcohol and formaldehyde

Correct Answer: