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Credit & Copyright: David McDavid (
Limber Observatory)
Explanation:
Clouds of glowing hydrogen gas mingle with dark dust lanes in
the Trifid Nebula,
a star forming region in the constellation Sagittarius.
In this and other similar emission
nebulae, energetic
ultraviolet light from an embedded hot young star strips
electrons from the surrounding
hydrogen atoms.
As the
electrons and atoms recombine they emit longer wavelength,
lower energy light in a well known
characteristic pattern of bright spectral lines.
At visible wavelengths,
the strongest emission line in this pattern is in the
red part of the spectrum and is known as "Hydrogen-alpha" or just H-alpha.
This image of the nebula was taken using a filter to select
only light near the H-alpha wavelength.
It shows those regions with substantial
emission from
atomic hydrogen.
The relative strength of this emission can trace the
densities of atoms within the gas cloud.
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Based on Astronomy Picture
Of the Day
Publications with keywords: H-alpha - emission nebula - atomic hydrogen
Publications with words: H-alpha - emission nebula - atomic hydrogen
See also: