|System:||Theta Octantis - All bodies|
|Distance to Sol:||217.16 ly|
|Spectral Class:||K - Scoopable|
|Luminosity Class:||III - Giant|
|Age:||4,938 Million years|
|Surface Temperature:||3,999 K|
Class K stars are yellow-orange main sequence stars with a long and generally stable life. They range in mass from 0.6 to 0.9 solar masses and have a surface temperature reaching 5,000 K.
A giant star is a star with substantially larger radius and luminosity than a main-sequence (or dwarf) star of the same surface temperature. They lie above the main sequence (luminosity class V in the Yerkes spectral classification) on the Hertzsprung–Russell diagram and correspond to luminosity classes II and III. The terms giant and dwarf were coined for stars of quite different luminosity despite similar temperature or spectral type by Ejnar Hertzsprung about 1905.
Giant stars have radii up to a few hundred times the Sun and luminosities between 10 and a few thousand times that of the Sun. Stars still more luminous than giants are referred to as supergiants and hypergiants.
A hot, luminous main-sequence star may also be referred to as a giant, but any main-sequence star is properly called a dwarf no matter how large and luminous it is.
A star becomes a giant star after all the hydrogen available for fusion at its core has been depleted and, as a result, leaves the main sequence. The behaviour of a post-main-sequence star depends largely on its mass.