Astrophysics (Index)About

K-type star

(K, K-class star)
(spectral class of star a bit cooler than the Sun)

A K-type star is a star within the K-class, a spectral class indicating stars with neutral metal and very weak hydrogen absorption lines, with an orange color, and a surface temperature in the 3700-5200 K range. The spectral energy distribution peaks in the near-infrared/visible range. Main sequence stars of this class (sometimes termed orange dwarfs or K dwarfs) are on the order of 3/4 solar masses, 3/4 solar radius, and 1/5 solar luminosity. Such main sequence stars burn their hydrogen in tens of billions of years. Characteristics of K-type main sequence stars:

6-8absolute magnitude(visual)
0.08-0.6bolometric luminosity(solar)
18-70 billion yearsmain-sequence lifetime

K-type main sequence stars are a good bet for habitable extra-solar planets, but offer few planets for study because the stars are much rarer than M-type stars and much dimmer than the hotter classes. Giant stars can also be of a K-type, including supergiants and hypergiants. Example K-type stars include Arcturus (a red giant), Epsilon Eridani, Epsilon Indi, J1407 (a subgiant), and TW Hydrae (a pre-main-sequence star).

(star type,spectral class)
Further reading:
527nm569THz2.4eVbeginK-type star
725nm414THz1.8eVendK-type star

Referenced by pages:
AB Pictoris (AB Pic)
barium star (Ba star)
calcium (Ca)
FGK star
G band
HD 189733 b
Kepler Telescope
M dwarf
Morgan classification
red dwarf
red giant
red-giant branch (RGB)
spectral class
Transiting Exoplanet Survey Satellite (TESS)
Tucana Horologium association (THA)
TW Hydrae association (TWA)
TW Hydrae (TW Hya)
Wilson-Bappu effect