Spectral Classes for Main Sequence Stars (table). The Columbia Encyclopedia, Sixth Edition. 2001-07

The Columbia Encyclopedia, Sixth Edition. 2001-07.

Spectral Classes for Main Sequence Stars (table)

Class	Color	Surface Temperature	Strong Lines
O	blue-white	35,000°C	ionized helium
B	blue-white	21,000°C	helium
A	white	10,000°C	hydrogen
F	creamy	7,000°C	ionized calcium
G	yellow	6,000°C	calcium
K	orange	4,500°C	titanium oxide
M	red	3,000°C	titanium oxide