A catalog of stars in which every star is classified by its stellar spectrum. This system is named for the astronomer Henry Draper, but was cataloged by Annie J. Cannon (225,300 stars), and later exte
nded by Margaret W. Mayall.
A catalog of stars in which every star is classified by its stellar spectrum. This system is named for the astronomer Henry Draper, but was cataloged by Annie J. Cannon (225,300 stars), and later exte
nded by Margaret W. Mayall.
A nearly horizontal path on the Hertzsprung-Russell diagram that a pre-main sequence star of small mass follows in an early stage of evolution after leaving the Hayashi track and before reaching the m
ain sequence. During this stage the pre-main sequence star remains almost wholly in radiative equilibrium.