Polaris australis
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Star Polaris Australis (σ Octantis) |
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| Polaris Australis (7) in the flag of Brazil | |||||||||||||||||
| AladinLite | |||||||||||||||||
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Observation dates equinox : J2000.0 , epoch : J2000.0 |
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| Constellation | Octant | ||||||||||||||||
| Right ascension | 21 h 08 m 46.2 s | ||||||||||||||||
| declination | -88 ° 57 ′ 23 ″ | ||||||||||||||||
| Apparent brightness | 5.42 mag | ||||||||||||||||
| Typing | |||||||||||||||||
| B − V color index | (0.32) | ||||||||||||||||
| Spectral class | F0 IV | ||||||||||||||||
| Variable star type | DSCTC | ||||||||||||||||
| Astrometry | |||||||||||||||||
| Radial velocity | (12 ± 2) km / s | ||||||||||||||||
| parallax | (11.09 ± 0.14) mas | ||||||||||||||||
| distance | (294 ± 4) ly (90) pc |
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| Proper movement | |||||||||||||||||
| Rec. Share: | (26.67 ± 0.25) mas / a | ||||||||||||||||
| Dec. portion: | (5.61 ± 0.27) mas / a | ||||||||||||||||
| Physical Properties | |||||||||||||||||
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Other names and catalog entries |
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Polaris Australis , also Sigma Octantis , σ Octantis or σ Oct , is a star in the constellation Octant and the star currently closest to the southern celestial pole that is visible to the naked eye.
Sigma Octantis, even Southern Pole Star , Südpolarstern or Südstern called represents the polar star of the southern hemisphere , and is thus the opposite of Polaris (α UMi) in the constellation Small bear as the Arctic star. However, due to its low apparent magnitude of 5.47 mag , the current southern polar star is only conditionally suitable as a navigation star. The star location of Polaris australis deviates according to the declination value by a little more than 1 ° from the south celestial pole.
The flag of Brazil shows a blue celestial sphere with stars from the southern sky , alongside 26 others also Polaris Australis, which in this context stands for the Distrito Federal do Brasil around the capital Brasília .
Web links
- The Constellations and their Stars; Polaris australis
- http://stars.astro.illinois.edu/sow/polaust.html