Omicron1_Centauri
Omicron1 Centauri
Star in the constellation Centaurus
Omicron1 Centauri (ο1 Cen, ο1 Centauri) is a star in the constellation Centaurus. It is approximately 10,000 light years from Earth.
ο1 Centauri is a yellow G-type supergiant or hypergiant with a mean apparent magnitude of +5.13. It is classified as a semiregular variable star and its brightness varies from magnitude +5.8 to +6.6 with a period of 200 days.[5] Other studies have reported only small brightness variations.[11][12] It is the MK spectral standard for class G3 O-Ia,[13] indicating a highly luminous mass-losing hypergiant star. It has also be classified as F8 Ia0[14] and F7 Ia/ab.[15] The size, luminosity, and distance are equally uncertain.
ο1 Cen forms a very close naked eye double star with ο2 Centauri, a hotter supergiant that may be physically associated. ο1 Cen also has an 11th magnitude companion only 13.5" distant,[16] Although it appears to be a foreground star unrelated to the other two.[17]