Sigma Octantis (σ Oct, σ Octantis) is a magnitude 5.6 star in the constellation Octans most notable for being the current South Star. Sigma Octantis is approximately 270 light years from Earth, and is classified as a giant, with a spectral type of F0 III. It is a Delta Scuti variable, with magnitude varying by about 0.03 magnitudes over 2.3 hours.
Sigma Octantis is the dimmest star to be represented on a national flag. It appears on the flag of Brazil, symbolising the Brazilian Federal District.
Its position near the southern celestial pole makes it the southern hemisphere's pole star, whence its occasional name, Polaris Australis.
Read more about Sigma Octantis: Southern Pole Star, Locating Sigma Octantis, See Also