Stellar Classifications

Table: Stellar classification

Class	Temperature	Conventional color	Apparent color	Mass (solar masses)	Radius (solar radii)	Luminosity	% of all Main Sequence Stars
O	30,000–60,000 K	blue	blue	60 M	15 R	1,400,000 L	~0.00003%
B	10,000–30,000 K	blue white	blue white to white	18 M	7 R	20,000 L	0.13%
A	7,500–10,000 K	white	white	3.1 M	2.1 R	80 L	0.6%
F	6,000–7,500 K	yellowish white	white	1.7 M	1.3 R	6 L	3%
G	5,000–6,000 K	yellow	yellow	1.1 M	1.1 R	1.2 L	8%
K	3,500–5,000 K	orange	yellow orange	0.8 M	0.9 R	0.4 L	13%
M	2,000–3,500 K	red	orange red	0.3 M	0.4 R	0.04 L	>78%

The Roman numeral following the Class indicates the luminosity of the star (not presently used here in SFC):

• I - super giant
• II - bright giant
• III - giant
• IV - sub-giant
• V - main sequence
• VI - sub-dwarf
• VII - white dwarf
• VIII - brown

Other Astronomical Objects

These objects are not necessary (or still) stars, nor necessarily natural:

• D - White Dwarf
• N - Nebula
• P - Neutron Star
• R - Rogue planet (this may be either a terrestrial planet or gas giant)
• T - Station (undesignated)
• U - Unknown (detected but unidentified)
• V - Black Hole