(Astr.), any of the types used to classify stellar spectra, each being associated with stars of a characteristic range of temperatures and…

The lengthening of the observed wavelength of light from celestial objects, as discerned from the displacement of spectral lines towards longer…

the reddening of starlight as a result of wavelength-dependent absorption and scattering by interstellar dust.

Astronomy. The way the intensity of radiation varies with wavelength from one side of a line in a stellar spectrum to the other; a diagrammatic…