He was studying the relationship between the spectral classification of stars and their actual brightness as corrected for distance their absolute magnitude.
22.
It is a bluish-white star of A7V spectral classification, meaning it has a surface temperature of 7, 500 to 11, 000 kelvins.
23.
Faint H? emission lines have been detected in the spectrum of 3 Geminorum, but this is not usually expressed in published spectral classifications.
24.
Under the Morgan-Keenan spectral classification scheme, planetary nebulae are classified as " Type-"'P " "', although this notation is seldom used in practice.
25.
When astronomers developed the spectral classification of the carbon stars, they had considerable difficulty when trying to correlate the spectra to the stars'effective temperatures.
26.
AD Leonis is a main sequence star with a spectral classification of M3.5V . It is a flare star that undergoes random increases in luminosity.
27.
White giant ( A ) ( spectral classification ), Catalogue number : 8 Mon, Brightness + 4.4, Distance in light years is 130 light years
28.
The Yerkes spectral classification system is a two-dimensional scheme that uses a letter and number combination to denote that temperature of a star ( e . g.
29.
The spectral classification of this star is F1III, which suggests it is an F-type that has evolved away from the main sequence and expanded into a giant star.
30.
The WO spectral classification had already been defined, but neither paper considered WR 30a to show sufficiently high excitation lines or strong oxygen lines to merit that classification.
