Nu Octantis

Nu Octantis
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Octans
Right ascension 21h 41m 28.65s[1]
Declination −77° 23′ 24.2″[1]
Apparent magnitude (V) 3.76[2]
Spectral typeK1III[3]

Nu Octantis is a spectroscopic binary[4] star in the constellation Octans. Its apparent magnitude is 3.76.[2] Located around 21.20 parsecs (69.1 ly) distant,[1] the primary is an orange giant of spectral type K1III,[3] a star that has used up its core hydrogen and has expanded.

In 2009, the system was hypothesized to contain an exoplanet based on perturbations in the orbital period.[5] A prograde solution was quickly ruled out[6] but a retrograde solution remains a possibility, although the variations may instead be due to the secondary star being itself a close binary[7] and the formation of a planet in the system is difficult due to dynamic perturbations.[8]

References

  1. 1 2 3 van Leeuwen, F. (November 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.
  2. 1 2 "Nu Octantis". SIMBAD Astronomical Database. Centre de Données astronomiques de Strasbourg. Retrieved 12 July 2015.
  3. 1 2 Gray, R. O.; et al. (July 2006). "Contributions to the Nearby Stars (NStars) Project: spectroscopy of stars earlier than M0 within 40 pc-The Southern Sample". The Astronomical Journal 132 (1): 161–170. arXiv:astro-ph/0603770. Bibcode:2006AJ....132..161G. doi:10.1086/504637.
  4. ↑ Eggleton, P. P.; Tokovinin, A. A. (September 2008). "A catalogue of multiplicity among bright stellar systems". Monthly Notices of the Royal Astronomical Society 389 (2): 869–879. arXiv:0806.2878. Bibcode:2008MNRAS.389..869E. doi:10.1111/j.1365-2966.2008.13596.x.
  5. ↑ Ramm, D. J.; Pourbaix, D.; Hearnshaw, J. B.; Komonjinda, S. (April 2009). "Spectroscopic orbits for K giants β Reticuli and ν Octantis: what is causing a low-amplitude radial velocity resonant perturbation in ν Oct?". Monthly Notices of the Royal Astronomical Society 394 (3): 1695–1710. Bibcode:2009MNRAS.394.1695R. doi:10.1111/j.1365-2966.2009.14459.x.
  6. ↑ Eberle, J.; Cuntz, M. (October 2010). "On the reality of the suggested planet in the ν Octantis system". The Astrophysical Journal 721 (2): L168–L171. Bibcode:2010ApJ...721L.168E. doi:10.1088/2041-8205/721/2/L168.
  7. ↑ Morais, M. H. M.; Correia, A. C. M. (February 2012). "Precession due to a close binary system: an alternative explanation for ν-Octantis?". Monthly Notices of the Royal Astronomical Society 419 (4): 3447–3456. arXiv:1110.3176. Bibcode:2012MNRAS.419.3447M. doi:10.1111/j.1365-2966.2011.19986.x.
  8. ↑ Gozdziewski, K.; Slonina, M.; Migaszewski, C.; Rozenkiewicz, A. (March 2013). "Testing a hypothesis of the ν Octantis planetary system". Monthly Notices of the Royal Astronomical Society 430 (1): 533–545. arXiv:1205.1341. Bibcode:2013MNRAS.430..533G. doi:10.1093/mnras/sts652.
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