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

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).
2. See also Hertzsprung-Russell diagram

Word History and Origins

Origin of spectral type¹

First recorded in 1920–25

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.

From Science News

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.

From Project Gutenberg

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

From Project Gutenberg

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

From Project Gutenberg

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

From Project Gutenberg

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

From Project Gutenberg