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spectral type

noun

, Astronomy.
  1. a category for classifying a star, as A star or G star, according to features of its spectrum, as its shape as a function of temperature and wavelength and its absorption spectrum, that indicate the surface temperature of the star and the presence of particular atoms or molecules in its outer layers: principal types are spectral types O, B, A, F, G, K, and M.


spectral type

noun

  1. any of various groups into which stars are classified according to characteristic spectral lines and bands. The most important classification ( Harvard classification ) has a series of classes O, B, A, F, G, K, M, the series also being a scale of diminishing surface temperature
“Collins English Dictionary — Complete & Unabridged” 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012


spectral type

  1. A classification system for stars based on the strength of their spectral lines, using the letters O, B, A, F, G, K, M, L, and T to denote a range from blue (as in blue giant stars) to dim red (as in brown dwarfs). The spectrum of a star correlates with its surface temperature, ranging from over 60,000°K (O type) to less than 3,500°K (L and T types).


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Word History and Origins

Origin of spectral type1

First recorded in 1920–25
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Example Sentences

In the new study, Hsu’s team analyzed 172 red and brown dwarfs of different spectral types, classifications based on the objects’ spectra that correlate with their surface temperatures.

Morey set to work at once with the telescope; trying to find the nearest star of spectral type G-0, as had been agreed upon.

As to the spectral type, the stars with great proper motions are all yellow or red stars.

We can therefore for each spectral type compute the mean values and the dispersion of these attributes.

On the distances and luminosities of stars of spectral type G as derived from their proper motions.

But even more remarkable is the connection between spectral type and speed of motion.

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