Subdwarf Stars
A subdwarf star, sometimes denoted by "sd", is luminosity class VI under the Yerkes spectral classification system. They are defined as stars with luminosity 1.5 to 2 magnitudes lower than that of main-sequence stars of the same spectral type. On an Hertzsprung–Russell diagram subdwarfs appear to lie below the main sequence.
The term "subdwarf" was coined by Gerard Kuiper in 1939, to refer to a series of stars with anomalous spectra that were previously labeled as "intermediate white dwarfs".
Read more about Subdwarf Stars: Cool Subdwarfs, Hot Subdwarfs, Notable Subdwarfs
Famous quotes containing the word stars:
“Art thou pale for weariness
Of climbing heaven and gazing on the earth,
Wandering companionless
Among the stars that have a different birth,”
—Percy Bysshe Shelley (1792–1822)