Article · Wikipedia archive · Last revised Jun 23, 2026

Delta Octantis

δ Octantis, Latinised as Delta Octantis, has the distinction of being Saturn's southern pole star. An orange giant of class K2III, it has 1.2 times the mass of the Sun and about 25 times the Sun's radius. This star is about 4.3 billion years old, which is similar to the age of the Sun.

Last revised
Jun 23, 2026
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δ Octantis
Location of δ Octantis (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Octans
Right ascension 14h 26m 55.23244s1
Declination −83° 40′ 04.3868″1
Apparent magnitude (V) 4.312
Characteristics
Spectral type K2III3
U−B color index +1.454
B−V color index +1.314
Astrometry
Radial velocity (Rv)+4.605 km/s
Proper motion (μ) RA: −96.121 mas/yr
Dec.: −13.271 mas/yr
Parallax (π)10.91±0.14 mas1
Distance299 ± 4 ly
(92 ± 1 pc)
Absolute magnitude (MV)−0.35±0.096
Details
Mass1.065 M☉
Radius24.615 R☉
Luminosity2712 L☉
Surface gravity (log g)1.895 cgs
Temperature4,3115 K
Metallicity [Fe/H]−0.425 dex
Rotational velocity (v sin i)1.17 km/s
Other designations
CD−83°189, GC 19349, HIP 70638, HR 5339, HD 124882, NSV 6636, SAO 258698
Database references
SIMBADdata

δ Octantis, Latinised as Delta Octantis, has the distinction of being Saturn's southern pole star.8 An orange giant of class K2III,3 it has 1.2 times the mass of the Sun and about 25 times the Sun's radius. This star is about 4.3 billion years old, which is similar to the age of the Sun.6

Naming

In Chinese caused by adaptation of the European southern hemisphere constellations into the Chinese system, 異雀 (Yì Què), meaning Exotic Bird, refers to an asterism consisting of δ Octantis, ζ Apodis, ι Apodis, β Apodis, γ Apodis, δ1 Apodis, η Apodis, α Apodis and ε Apodis. Consequently, δ Octantis itself is known as 異雀五 (Yì Què wǔ, English: the Fifth Star of Exotic Bird).9

References

References

  1. Van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653–664. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. S2CID 18759600. Vizier catalog entry
  2. Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters. 38 (5): 331. arXiv:1108.4971. Bibcode:2012AstL...38..331A. doi:10.1134/S1063773712050015. S2CID 119257644. Vizier catalog entry
  3. Hoffleit, D.; Warren, W. H. (1995). "VizieR Online Data Catalog: Bright Star Catalogue, 5th Revised Ed. (Hoffleit+, 1991)". VizieR On-line Data Catalog: V/50. Originally Published in: 1964BS....C......0H. 5050. Bibcode:1995yCat.5050....0H.
  4. Mallama, A. (2014). "Sloan Magnitudes for the Brightest Stars". The Journal of the American Association of Variable Star Observers. 42 (2): 443. Bibcode:2014JAVSO..42..443M.Vizier catalog entry
  5. Jofré, E.; Petrucci, R.; Saffe, C.; Saker, L.; Artur de la Villarmois, E.; Chavero, C.; Gómez, M.; Mauas, P. J. D. (2015). "Stellar parameters and chemical abundances of 223 evolved stars with and without planets". Astronomy & Astrophysics. 574: A50. arXiv:1410.6422. Bibcode:2015A&A...574A..50J. doi:10.1051/0004-6361/201424474. S2CID 53666931. Vizier catalog entry
  6. da Silva, L.; et al. (November 2006), "Basic physical parameters of a selected sample of evolved stars", Astronomy and Astrophysics, 458 (2): 609–623, arXiv:astro-ph/0608160, Bibcode:2006A&A...458..609D, doi:10.1051/0004-6361:20065105, S2CID 9341088
  7. De Medeiros, J. R.; Alves, S.; Udry, S.; Andersen, J.; Nordström, B.; Mayor, M. (2014). "A catalog of rotational and radial velocities for evolved stars". Astronomy & Astrophysics. 561: A126. arXiv:1312.3474. Bibcode:2014A&A...561A.126D. doi:10.1051/0004-6361/201220762. S2CID 54046583. Vizier catalog entry
  8. "Octans". UK Astronomy Society. Archived from the original on 1 August 2020. Retrieved 10 October 2011.
  9. (in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 29 日 Archived 2011-05-22 at the Wayback Machine