Kaus Australis (Epsilon Sagittarii)

Kaus Australis (Epsilon Sagittarii) is the brightest star in the constellation Sagittarius; it marks the southern (Latin australis) extremity of the Archer's bow (Arabic kaus) and is also the lower right star of the Milk Dipper asterism. Deep in the southern hemisphere, 34° below the celestial equator, the star is not well known to northerners, though it is the 36th brightest star in the sky. It has traditionally been called a giant and assigned to the cool end of B, while others have more recently assigned it to hot-end class A as a bright giant. In any event, the star is much brighter than its main sequence counterparts and is clearly in a more advanced state. It probably has a core of helium that is shrinking and heating as it prepares to fuse to carbon and oxygen. It may also be a sort of shell star in which its high rotation speed (over 70 times that of the Sun) was responsible for creating a shell of gas that hides much of the star within
| visual magnitude | 1.79 |
| absolute magnitude | -1.45 |
| spectral type | B9.5III |
| surface temperature | 9,200 K |
| luminosity | 375 Lsun |
| radius | 7 Rsun |
| mass | 4 Msun |
| distance | 145 light-years |
| position | RA 18h 24m 10.3s, Dec -34° 23' 5" |
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