The blanketing effect (also referred to as line blanketing or the line-blanketing effect) is the enhancement of the
red
Red is the color at the long wavelength end of the visible spectrum of light, next to orange and opposite violet. It has a dominant wavelength of approximately 625–740 nanometres. It is a primary color in the RGB color model and a secondar ...
or
infrared
Infrared (IR), sometimes called infrared light, is electromagnetic radiation (EMR) with wavelengths longer than those of visible light. It is therefore invisible to the human eye. IR is generally understood to encompass wavelengths from around ...
regions of a
stellar spectrum at the expense of the other regions, with an overall diminishing effect on the whole spectrum. The term originates in a 1928 article by astrophysicist
Edward Arthur Milne
Edward Arthur Milne FRS (; 14 February 1896 – 21 September 1950) was a British astrophysicist and mathematician.
Biography
Milne was born in Hull, Yorkshire, England. He attended Hymers College and from there he won an open scholarship ...
, where it was used to describe the effects that the
astronomical metals in a star's outer regions had on that star's spectrum. The name arose because the absorption lines act as a "blanket", causing the continuum temperature of the spectrum to rise over what it would have been if these lines were not present.
Astronomical metals, which produce most of a star's spectral
absorption lines, absorb a fraction of the star's
radiant energy
Radiant may refer to:
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* Radiant (software), a content management system
* GtkRadiant, a level editor created by id Software for their games
* Radiant AI, a technology developed by Bethesda Softworks for '' ...
(a phenomenon known as the ''blocking effect'') and then re-emit it at a lower frequency as part of the ''backwarming'' effect.
The combination of both these effects results in the position of stars in a
color-color diagram to shift towards redder areas as the proportion of ''metals'' in them increases. The blanketing effect is thus highly dependent on the
metallicity index of a star, which indicates the fraction of elements other than hydrogen and helium that compose it.
References
External links
"Line-Blanketing Effects on the uvbyβ Photometric System"; McNamara, D. H. & Colton, D. J. (1969)* {{cite book, author=David J. Darling, title=The universal book of astronomy: from the Andromeda Galaxy to the zone of avoidance, url=https://books.google.com/books?id=L5zuAAAAMAAJ, year=2004, publisher=Wiley, isbn=978-0-471-26569-6, page=293
Metallicity and the spectral energy distribution of O stars Martín-Hernández, N. L., Mokiem, M. R., de Koter, A. & Tielens, A. G. G. M. (2002)
Line Blanketing Oxford Articles, May 2013
Astronomy