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<TD vAlign=center width="23%"> <h5 align=center><b>Temperature | <TD vAlign=center width="23%"> <h5 align=center><b>Temperature | ||
(K)</b></h5></TD> | (K)</b></h5></TD> | ||
<TD vAlign=center width="53%"> <h5 align=center><strong>Composition</strong></h5></TD> | <TD vAlign=center width="53%"> <h5 align=center><strong>Composition | ||
</strong></h5></TD> | |||
</TR> | </TR> | ||
<TR> | <TR> | ||
Revision as of 00:46, 8 January 2009
Spectral (Stellar) Classification Ssystem
The original version of the current MK system was defined by Morgan, Keenan, and Kellman (1943), and a revised list of standards was published in 1953 by Morgan and Johnson. Additional refinements have been added since then.
MK Spectral Classification System (Standard)
Class |
Color |
Temperature (K) |
Composition |
| O |
Dark Blue |
28,000-50,000 |
ionized atoms, especially helium |
| B |
Blue |
10,000-28,000 |
neutral helium, some hydrogen |
| A |
Light Blue |
7,500-10,000 |
strong hydrogen, some ionized metals |
| F |
White |
6,000-7,500 |
hydrogen and ionized metals; calcium and iron |
| G |
Yellow |
5,000-6,000 |
ionized calcium; both neutral and ionized metals |
| K |
Orange |
3,500-5,000 |
Neutral metals |
| M |
Red |
2,500-3,500 |
Strong molecules; titanium oxide, neutral calcium |
