In the visible spectrum Sirius is the brightest star in the night sky, while in the near-infrared J-band, Betelgeuse is the brightest star in the night sky.

Arcturus is a type K1. 5 IIIpe orange giant star — the letters " pe " stand for " peculiar emission ," which indicates that the spectrum of light given off by the star is unusual and full of emission lines.

Its visual luminosity is about 10, 000 times that of the Sun, but because the star radiates a considerable part of its energy in the infrared part of the spectrum, the bolometric luminosity equals roughly 65, 000 times that of the Sun.

A third category was added in 1912 when Vesto Slipher showed that the spectrum of the nebula that surrounded the star Merope matched the spectra of the Pleiades open cluster.

Astronomers detected what appeared to be a faint blue star at the location of the radio source and obtained its spectrum.

Since 1943, the spectrum of this star has served as one of the stable anchor points by which other stars are classified.

Astronomers can determine the mass, age, chemical composition and many other properties of a star by observing its spectrum, luminosity and motion through space.

Light from the star is analyzed by splitting it up by a diffraction grating, subdividing the incoming photons into a spectrum exhibiting a rainbow of colors interspersed by absorption lines, each line indicating a certain ion of a certain chemical element.

In the current star classification system, the Morgan-Keenan system, the spectrum letter is enhanced by a number from 0 to 9 indicating tenths of the range between two star classes, so that A5 is five tenths between A0 and F0, and A2 is two tenths of the full range from A0 to F0.

Zeta Trianguli Australis appears as a star of apparent magnitude + 4. 91 and spectral class F9V, yet is actually a spectroscopic binary with a companion whose spectrum and identity are unknown yet likely to be a red dwarf.

Due to the Doppler shift, the absorption lines in the spectrum of a star will be shifted slightly toward the red ( or longer wavelengths ) if the star is moving away from the observer, or toward blue ( or shorter wavelengths ) when it moves toward the observer.

Due to the Doppler effect, the rotation rate of a star affects the width of the absorption lines in the spectrum.

Besides rotation, another factor that can widen the absorption features in the spectrum of a star is pressure-broadening.

Vega was the first star other than the Sun to be photographed and the first to have its spectrum recorded.

Henry Draper took the first photograph of a star's spectrum in August 1872 when he took an image of Vega, and he also became the first person to show absorption lines in the spectrum of a star.

Since 1943, the spectrum of this star has served as one of the stable anchor points by which other stars are classified.

This piece of apparently routine work proved very fruitful — it led to the discovery that all the stars of very faint absolute magnitude were of spectral class M. In conversation on this subject ( as I recall it ), I asked Pickering about certain other faint stars, not on my list, mentioning in particular 40 Eridani B. Characteristically, he sent a note to the Observatory office and before long the answer came ( I think from Mrs Fleming ) that the spectrum of this star was A. I knew enough about it, even in these paleozoic days, to realize at once that there was an extreme inconsistency between what we would then have called " possible " values of the surface brightness and density.

The radiation from the protostar and early star has to be observed in infrared astronomy wavelengths, as the extinction caused by the rest of the cloud in which the star is forming is usually too big to allow us to observe it in the visual part of the spectrum.

Accordingly, the technique of " Fourier transform spectroscopy " can be used both for measuring emission spectra ( for example, the emission spectrum of a star ), and absorption spectra ( for example, the absorption spectrum of a liquid ).

which matches the energy spectrum which we gave in the preceding section.

The spectrum of this star matches a stellar classification of, with the luminosity class of III indicating that it is an evolved giant star that has exhausted the supply of hydrogen at its core and is now on the red giant branch.

The spectrum matches a star with a stellar classification of B1 III, with the luminosity class of III indicating this is a giant star that has exhausted the hydrogen at its core and evolved away from the main sequence.

Hence they have the same stellar classification of F8Vp, which matches the spectrum of a main sequence star that is generating energy through the nuclear fusion of hydrogen.

The spectrum of this star matches a stellar classification of G2 IV, with the luminosity class of ' IV ' indicating this is a subgiant star.

When using three separate LEDs ( additive color ) the backlight can produce a color spectrum that closely matches the color filters in the LCD pixels themselves.

The spectrum of Alpha Persei matches a stellar classification of F5 Ib, revealing it to be a supergiant star in the latter stages of its evolution.

The spectrum of this star matches a stellar classification of M3 III, which places it among the category of evolved stars called red giants.

The spectrum matches a stellar classification of A1 IV.

The combined stellar classification of the system is K0. 5 IIIb, which matches the spectrum of a lower luminosity giant star.

First, the spectrum of the gamma-rays seen by RHESSI matches very well to the prediction of relativistic runaway at 15 – 20 km.

The spectrum of this star matches a stellar classification of G8 Ib, where the luminosity class of Ib indicates this is a lower luminosity supergiant star.

The spectrum of this star matches a stellar classification of F2 II.

The spectrum of Skat matches a stellar classification of A3 V, indicating this is an A-type main sequence star that is generating energy through the nuclear fusion of hydrogen at its core.

The combined spectrum of this pair matches a star with a stellar classification of B1. 5 III.

The spectrum matches a stellar classification of.

The spectrum matches a stellar classification of G2 Ib – IIa, with the luminosity class notation Ib – IIa indicating it lies part way between the bright giant and supergiant stages of its stellar evolution.

The spectrum matches a stellar classification of K0 III-IV, with the luminosity class of III-IV corresponding to an evolved star that lies between the subgiant and giant stages.

The spectrum of the star matches a stellar classification of B3 IV, where the luminosity class of ' IV ' indicates this is a subgiant star that has nearly exhausted the supply of hydrogen at its core and is evolving away from the main sequence.

The spectrum of this star matches a stellar classification of A1 V, which identifies it as an A-type main sequence star that is generating energy through the nuclear fusion of hydrogen at its core.

The spectrum of this star matches a stellar classification of K1 III, with the luminosity class of ' III ' indicating this is an evolved giant star that has exhausted the supply of hydrogen at its core.

The spectrum of the primary matches a stellar classification of G8 III-IV, suggesting that it is an evolved star that lies part way between the subgiant and giant stages.

The spectrum of this star matches a stellar classification of A5 V, indicating that it is an A-type main sequence star.

This star has a stellar classification of A2 V, which matches the spectrum of an A-type main sequence star.