||Surface Temperature (K)
||Relatively few absorption lines. Lines of
ionized helium and other lines of highly ionized atoms. Hydrogen lines
appear only weakly. Peak of light in UV part of spectrum.
||Lines of neutral helium. Hydrogen lines more pronounced than
in O-type stars. He I lines strong, as well as C II, O II, Si III.
||Bluish-white to white
||Strong lines of hydrogen. Also lines of singly ionized
magnesium, silicon, iron, titanium, calcium, and others. Lines of some
neutral metals show weakly.
||white to yellowish-white
||Hydrogen lines are weaker than in A-type star but still
conspicuous. Lines of singly ionized metals are present (Ca II), as are
lines of other neutral metals.
||yellow to yellowish-white
||Lines of ionized calcium (Ca II) are the most conspicuous.
Many lines of ionized and neutral metals are present. Hydrogen lines
are weaker even than in F-type stars.
||Lines of neutral metals predominate. Hydrogen very weak,
molecular bands start to appear.
||Strong lines of neutral metals and molecules.
||Visible mainly in the infrared part of the spectrum. Strong
lines of neutral metals and molecules, including water, CO, TiO, FeH, O2.
||Less than 1,400
||Visible almost entirely at Infrared wavelengths, shows strong