Jump to content

Alpha Octantis

From Wikipedia, the free encyclopedia
Alpha Octantis

A light curve for Alpha Octantis plotted from TESS data[1]
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Octans
Right ascension 21h 04m 43.06347s[2]
Declination −77° 01′ 25.5735″[2]
Apparent magnitude (V) 5.13[3]
Characteristics
Evolutionary stage Main sequence[4]
Spectral type F4III + F5III[5]
U−B color index +0.13[6]
B−V color index +0.490±0.008[3]
Variable type EB[7]
Astrometry
Radial velocity (Rv)85.9±1.5[3] km/s
Proper motion (μ) RA: +22.5215[2] mas/yr
Dec.: −369.325[2] mas/yr
Parallax (π)22.5215±0.0955 mas[2]
Distance144.8 ± 0.6 ly
(44.4 ± 0.2 pc)
Absolute magnitude (MV)1.93±0.02[8]
Orbit[5]
Period (P)9.073 d
Eccentricity (e)0.39
Periastron epoch (T)2,435,302.404
Argument of periastron (ω)
(secondary)		276°
Semi-amplitude (K1)
(primary)		47 km/s
Semi-amplitude (K2)
(secondary)		47 km/s
Details
A
Mass1.9[9] M☉
Radius2.0[4] R☉
Luminosity7[4] L☉
Temperature6,700[4] K
Age1.1[9] Gyr
B
Mass2[4] M☉
Radius2.0[4] R☉
Luminosity7[4] L☉
Temperature6,700[4] K
Age1.1[9] Gyr
Other designations
α Oct, CD−77°1053, CPD−77°1474, FK5 787, GC 29343, HD 199532, HIP 104043, HR 8021, SAO 257879, PPM 374864, LTT 8327, NLTT 50332[10]
Database references
SIMBADdata

Alpha Octantis is a binary star[11] system in the constellation of Octans. The name is Latinized from α Octantis. Despite being labeled the "alpha" star by Lacaille, it is not the brightest star in the constellation—that title belongs to Nu Octantis. It is visible to the naked eye as a faint, yellow-white-hued point of light with an overall apparent visual magnitude of approximately 5.13.[3] The system is located approximately 148 light-years away from the Sun based on parallax.

This is a double-lined spectroscopic binary star which consists of two similar main sequence stars, each with spectral type F,[4] orbiting each other with a period of just over 9 days and an eccentricity of 0.39.[5] The pair form a Beta Lyrae-type eclipsing binary system, dropping by magnitude 0.04 during the primary eclipse.[7] This system is a bright X-ray source with a luminosity of 22.78×1029 ergs s−1.[12] The system displays an infrared excess suggesting the presence of a debris disk; with a temperature of 219 K and is orbiting at a distance of 9.8 AU from its host star.[13]

References

[edit]
  1. ^ "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute. Retrieved 8 December 2021.
  2. ^ a b c d e Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
  3. ^ a b c d 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.
  4. ^ a b c d e f g h i "Alpha Octantis". stars.astro.illinois.edu. Retrieved 2025-07-13.
  5. ^ a b c The double-lined binary alpha Octantis, William Buscombe and Pamela M. Morris, The Observatory 80 (February 1960), pp. 28–29, Bibcode:1960Obs....80...28B.
  6. ^ HR 8021, database entry, The Bright Star Catalogue, 5th Revised Ed. (Preliminary Version), D. Hoffleit and W. H. Warren, Jr., CDS ID V/50. Accessed on line September 4, 2008.
  7. ^ a b Samus', N. N; et al. (2017). "General catalogue of variable stars". Astronomy Reports. 5.1. 61 (1): 80. Bibcode:2017ARep...61...80S. doi:10.1134/S1063772917010085. S2CID 125853869.
  8. ^ Nordström, B.; et al. (2004). "The Geneva-Copenhagen survey of the Solar neighbourhood. Ages, metallicities, and kinematic properties of ˜14 000 F and G dwarfs". Astronomy and Astrophysics. 418: 989–1019. arXiv:astro-ph/0405198. Bibcode:2004A&A...418..989N. doi:10.1051/0004-6361:20035959. S2CID 11027621.
  9. ^ a b c Asensio-Torres, R.; Janson, M.; Bonavita, M.; Desidera, S.; Thalmann, C.; Kuzuhara, M.; Henning, Th; Marzari, F.; Meyer, M. R.; Calissendorff, P.; Uyama, T. (2018-11-01). "SPOTS: The Search for Planets Orbiting Two Stars - III. Complete sample and statistical analysis". Astronomy & Astrophysics. 619: A43. doi:10.1051/0004-6361/201833349. ISSN 0004-6361.
  10. ^ "* alf Oct". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved September 4, 2008.
  11. ^ 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. S2CID 14878976.
  12. ^ Makarov, Valeri V. (October 2003), "The 100 Brightest X-Ray Stars within 50 Parsecs of the Sun", The Astronomical Journal, 126 (4): 1996–2008, Bibcode:2003AJ....126.1996M, doi:10.1086/378164.
  13. ^ Trilling, D.E.; Stansberry, J.A.; Stapelfeldt, K.R.; Rieke, G.H.; Su, K.Y.L; Gray, R.O; Corbally, C.J; Bryden, G; Chen, C.H.; Boden, A; Beichman, C.A (2007). "DEBRIS DISKS IN MAIN-SEQUENCE BINARY SYSTEMS" (PDF). The Astrophysical Journal. 658 (2): 1289-1311. Bibcode:2007ApJ...658.1289T. doi:10.1086/511668.
Retrieved from "https://en.wikipedia.org/w/index.php?title=Alpha_Octantis&oldid=1300294642"