K
Stellar classification

K
Effective temperature
3,500–5,000 K
Solar radius
0.7–0.96 R☉
Solar mass
0.45–0.8 M☉

A K-type main-sequence star (K V), also referred to as an orange dwarf or K dwarf, is a main-sequence (hydrogen-burning) star of spectral type K and luminosity class V. These stars are intermediate in size between red M-type main-sequence stars and yellow G-type main-sequence stars. They have masses between 0.45 to 0.8 times the mass of the Sun and surface temperatures between 3,900 and 5,200 K., Tables VII, VIII. Better-known examples include Alpha Centauri B (K1 V) and Epsilon Indi. These stars are of particular interest in the search for extraterrestrial life because they are stable on the main sequence for a very long time (15 to 30 billion years, compared to 10 billion for the Sun). This may create an opportunity for life to evolve on terrestrial planets orbiting such stars. K-type stars also emit less ultraviolet radiation (which can damage DNA and thus hamper the emergence of life) than G-type stars like the Sun. K-type main-sequence stars are about three to four times as abundant as G-type main-sequence stars, making planet searches easier.

Uses material from the Wikipedia article "K-type main-sequence star", which is released under the Creative Commons BY-SA 3.0.
Astronomical object DistanceWiki
1 AurigaeStar, Infra-Red sourceK504[x]
1 PegasiStar, Double or multiple star, Infra-Red source, Spectroscopic binary, UV-emission sourceK156[x]
109 HerculisStar, Double or multiple star, Infra-Red source, High proper-motion Star, UV-emission source, Variable StarK119[x]
11 CepheiStar, Infra-Red source, High proper-motion Star, UV-emission sourceK182[x]
12 AquariiStar, Double or multiple starK106[x]
14 HerculisStar, Double or multiple star, Infra-Red source, High proper-motion StarK58[x]
15 EridaniStar, Double or multiple star, Infra-Red source, UV-emission sourceK255[x]
25 ScorpiiStar, Infra-Red sourceK706[x]
3 AndromedaeStar, Infra-Red source, High proper-motion StarK176[x]
3 PerseiStar, Infra-Red sourceK245[x]
30 GeminorumStar, Double or multiple star, Infra-Red source, High proper-motion Star, UV-emission sourceK289[x]
31 OrionisStar, Double or multiple star, Infra-Red source, Variable StarK508[x]
36 AndromedaeStar, Double or multiple star, Infra-Red source, Variable StarK124[x]
36 OphiuchiStar, Double or multiple star, Infra-Red sourceK19[x]
37 LibraeStar, Infra-Red source, High proper-motion Star, UV-emission sourceK94[x]
39 ArietisStar, Infra-Red source, High proper-motion Star, UV-emission sourceK171[x]
41 CapricorniStar, Double or multiple star, Infra-Red sourceK231[x]
42 DraconisStar, Infra-Red source, High proper-motion Star, UV-emission sourceK315[x]
43 TauriStar, Infra-Red source, UV-emission sourceK284[x]
47 AquariiStar, Infra-Red source, Red giantK171[x]
49 ArietisStar, Infra-Red source, UV-emission source, Variable Star210[x]
54 PisciumStar, Infra-Red source, High proper-motion Star, Rotationally variable Star, Variable Star, X-ray sourceK36[x]
56 CetiStar, Infra-Red sourceK353[x]
6 DraconisStar, Infra-Red sourceK602[x]
6 LyncisStar, Double or multiple star, Infra-Red source, High proper-motion StarK182[x]
6 SagittariiStar, Infra-Red sourceK2631[x]
61 CygniStar, Double or multiple star, Infra-Red source, X-ray sourceK11[x]
64 ArietisStar, Infra-Red sourceK208[x]
66 ArietisStar, Double or multiple star, Infra-Red source, UV-emission sourceK210[x]
70 OphiuchiStar, Double or multiple star, Variable of BY Dra type, Infra-Red source, High proper-motion Star, Spectroscopic binary, UV-emission source, Variable Star, X-ray sourceK16[x]
75 TauriStar, Double or multiple star, Star in Cluster, Infra-Red source, UV-emission source, Variable StarK186[x]
77 AquariiStar, Infra-Red source, High proper-motion Star, Variable StarK134[x]
8 PerseiStar, Infra-Red sourceK411[x]
9 HydraeStar, Double or multiple star, Infra-Red source, High proper-motion Star, UV-emission sourceK212[x]
93 HerculisStar, Infra-Red source, UV-emission sourceK671[x]
98 AquariiStar, Infra-Red source, UV-emission sourceK164[x]
A BootisStar, Infra-Red source, Spectroscopic binary, UV-emission sourceK234[x]
AB PictorisStar, Variable of BY Dra type, Infra-Red source, Pre-main sequence Star, UV-emission source, Variable Star, X-ray sourceK150[x]
AdhilStar, Infra-Red sourceK215[x]
AlbireoStar, Double or multiple star, Star in double system, Infra-Red source, Variable StarK435[x]
AldebaranStar, Double or multiple star, Infra-Red source, Long Period Variable candidate, High proper-motion Star, UV-emission source, Variable StarK67[x]
AlgiebaStar, Double or multiple star, Infra-Red sourceK130[x]
Alpha AntliaeStar, Infra-Red source, Variable StarK366[x]
Alpha HorologiiStar, Infra-Red source, High proper-motion Star, UV-emission sourceK115[x]
Alpha IndiStar, Double or multiple star, Infra-Red source, UV-emission sourceK98[x]
Alpha ScutiStar, Infra-Red source, High proper-motion Star, UV-emission source, Variable StarK199[x]
Alpha TucanaeStar, Double or multiple star, Infra-Red source, Spectroscopic binary, UV-emission sourceK200[x]
Alpha VolantisStar, Double or multiple star, Infra-Red source, UV-emission source125[x]
AlphardStar, Double or multiple star, Infra-Red source, High proper-motion Star, UV-emission source, Variable StarK180[x]
AlsciaukatStar, Infra-Red source, Semi-regular pulsating Star, Variable StarK382[x]
AngetenarStar, Double or multiple star, Infra-Red source, UV-emission source, X-ray sourceK187[x]
AnkaaStar, Infra-Red source, High proper-motion Star, Spectroscopic binary, UV-emission sourceK85[x]
ArcturusStar, Infra-Red source, High proper-motion Star, Red giant, UV-emission source, Variable StarK37[x]
Asellus AustralisStar, Double or multiple star, Infra-Red source, High proper-motion Star, UV-emission sourceK131[x]
AviorStar, Double or multiple star, Infra-Red source, UV-emission source, Variable StarK605[x]
AzhaStar, Infra-Red source, High proper-motion Star, UV-emission source, Variable StarK136[x]
b CapricorniStar, Infra-Red source, UV-emission sourceK171[x]
B CentauriStar, Infra-Red sourceK433[x]
Baten KaitosStar, Double or multiple star, Infra-Red source, Spectroscopic binary, UV-emission source, Variable StarK235[x]
BD+05 1295Star, Double or multiple star, Star in Cluster, Infra-Red source, High proper-motion StarK114[x]
BD+14 4559Star, Infra-Red source, High proper-motion StarK158[x]
BD+26 2184Star, Infra-Red sourceK69[x]
BD+75 58Star, Infra-Red sourceK55[x]
BD-01 2784Star, Infra-Red sourceK67[x]
Beta ReticuliStar, Double or multiple star, Infra-Red source, High proper-motion Star, Spectroscopic binary, UV-emission sourceK100[x]
Beta VolantisStar, Infra-Red source, Variable StarK108[x]
BO MicroscopiiStar, Variable of BY Dra type, Infra-Red source, Pre-main sequence Star, UV-emission source, Variable Star, X-ray sourceK145[x]
BoteinStar, Infra-Red source, High proper-motion Star, UV-emission source, Variable StarK169[x]
BundaStar, Double or multiple star, Infra-Red source, High proper-motion Star, Spectroscopic binary, UV-emission sourceK73[x]
BY DraconisStar, Double or multiple star, Variable of BY Dra type, Flare Star, Infra-Red source, High proper-motion Star, Radio-source, Spectroscopic binary, UV-emission source, Variable Star, X-ray sourceK53[x]
CebalraiStar, Infra-Red source, High proper-motion Star, UV-emission source, Variable StarK82[x]
CF 17413Star, Infra-Red source, Pre-main sequence Star, X-ray sourceK96[x]
CO CamelopardalisStar, Ellipsoidal variable Star, Infra-Red source, Spectroscopic binary, UV-emission source, Variable Star, X-ray source109[x]
D CentauriStar, Double or multiple star, Infra-Red sourceK572[x]
DE BootisStar, Infra-Red source, High proper-motion Star, Variable of RS CVn type, Spectroscopic binary, UV-emission source, Variable Star, X-ray sourceK38[x]
Delta AndromedaeStar, Double or multiple star, Infra-Red source, High proper-motion Star, Spectroscopic binary, UV-emission source, Variable StarK105[x]
Delta AurigaeStar, Double or multiple star, Infra-Red source, High proper-motion Star, Spectroscopic binary, UV-emission sourceK141[x]
Delta LeporisStar, Infra-Red source, High proper-motion Star, UV-emission sourceK113[x]
Delta MuscaeStar, Infra-Red source, High proper-motion Star, Spectroscopic binaryK90[x]
Delta NormaeStar, Infra-Red source, UV-emission source123[x]
Delta OctantisStar, Infra-Red source, High proper-motion Star, Variable StarK299[x]
Deneb AlgediStar, Double or multiple star, Eclipsing binary of Algol type , Infra-Red source, High proper-motion Star, Spectroscopic binary, UV-emission source, Variable Star, X-ray source39[x]
DiphdaStar, Infra-Red source, High proper-motion Star, UV-emission source, Variable Star, X-ray sourceK96[x]
e CentauriStar, Infra-Red sourceK294[x]
EnifStar, Double or multiple star, Infra-Red source, Long-period variable star, Peculiar Star, UV-emission source, Variable StarK690[x]
EP EridaniStar, Double or multiple star, Flare Star, Infra-Red source, High proper-motion Star, Rotationally variable Star, Variable of RS CVn type, UV-emission source, Variable Star, X-ray sourceK34[x]
Epsilon CirciniStar, Infra-Red sourceK408[x]
Epsilon CrucisStar, Infra-Red source, High proper-motion Star, Variable StarK230[x]
Epsilon CygniStar, Double or multiple star, Infra-Red source, High proper-motion Star, UV-emission sourceK72[x]
Epsilon EridaniStar, Double or multiple star, Variable of BY Dra type, Infra-Red source, High proper-motion Star, Rotationally variable Star, UV-emission source, Variable Star, X-ray sourceK11[x]
Epsilon FornacisStar, Infra-Red source, High proper-motion Star, UV-emission sourceK105[x]
Epsilon IndiStar, Double or multiple star, Infra-Red source, High proper-motion Star, Pre-main sequence Star, UV-emission source, X-ray sourceK12[x]
Epsilon PhoenicisStar, Infra-Red source, High proper-motion Star, UV-emission sourceK145[x]
Epsilon ReticuliStar, Double or multiple star, Infra-Red source, High proper-motion Star, UV-emission sourceK59[x]
Epsilon ScorpiiStar, Infra-Red source, High proper-motion Star, UV-emission source, Variable Star, X-ray sourceK64[x]
Epsilon SerpentisStar, Infra-Red source, UV-emission source70[x]
Epsilon Trianguli AustralisStar, Double or multiple star, Infra-Red sourceK202[x]
Eta CepheiStar, Double or multiple star, Infra-Red source, High proper-motion Star, UV-emission sourceK46[x]
Eta ScutiStar, Infra-Red source, UV-emission sourceK202[x]
Eta SerpentisStar, Double or multiple star, Infra-Red source, High proper-motion Star, UV-emission source, Variable StarK61[x]