Binary star system in the constellation Octans
Alpha Octantis Observation dataEpoch 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 Spectral type F4III + F5III(spectroscopic binary) [ 4] U−Bcolor index +0.13[ 5] B−Vcolor index ± 0.008[ 3] Variable type EB [ 6] Astrometry Radial velocity (Rv )± 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] Distance 144.8 ± 0.6 ly pc ) Absolute magnitude (MV )± 0.02[ 7] Orbit [ 4] Period (P)9.073 d Eccentricity (e)0.39 Periastron epoch (T)2,435,302.404 Argument of periastron (ω)276° Semi-amplitude 1 )47 km/s Semi-amplitude (K2 )47 km/s Details Mass 1.42[ 8] M ☉ Radius 3.69[ 9] R ☉ Temperature 6,270[ 7] K Metallicity 0.07[ 7] dex Rotational velocity (v sin i )85[ 10] Age ± 0.1[ 7] Gyr Other designations α Oct ,CD −77°1053CPD −77°1474FK5 787GC 29343HD 199532HIP 104043HR 8021SAO 257879PPM 374864LTT 8327NLTT 50332[ 11] Database references SIMBAD data
Alpha Octantis is abinary star [ 12] constellation ofOctans . The name isLatinized from α Octantis. Despite being labeled the "alpha" star byLacaille , it is not the brightest star in the constellation—that title belongs toNu Octantis . It is visible to the naked eye as a faint, yellow-white-hued point of light with an overallapparent visual magnitude of approximately 5.13.[ 3] light-years away from theSun based onparallax .
This is a double-linedspectroscopic binary star which consists of two similargiant stars , each withspectral type F, orbiting each other with aperiod of just over 9 days and aneccentricity of 0.39.[ 4] Beta Lyrae-type eclipsing binary system, dropping by magnitude 0.04 during the primary eclipse.[ 6] X-ray source with a luminosity of× 1029 ergs s−1 [ 13] infrared excess suggesting the presence of adebris disk ; with a temperature ofK AU [ 14]
^ "MAST: Barbara A. Mikulski Archive for Space Telescopes" . Space Telescope Science Institute. Retrieved8 December 2021 .^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 atVizieR .^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 . ^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 . ^ HR 8021 , database entry, The Bright Star Catalogue, 5th Revised Ed. (Preliminary Version), D. Hoffleit and W. H. Warren, Jr.,CDS IDV/50 . Accessed on line September 4, 2008.^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 . ^a b c d 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 . ^ Tokovinin, A.; et al. (May 2006), "Tertiary companions to close spectroscopic binaries",Astronomy and Astrophysics ,450 (2):681– 693,arXiv :astro-ph/0601518 Bibcode :2006A&A...450..681T ,doi :10.1051/0004-6361:20054427 ,S2CID 8899546 ^ Cotten, Tara H.; Song, Inseok (July 2016), "A Comprehensive Census of Nearby Infrared Excess Stars",The Astrophysical Journal Supplement Series ,225 (1): 24,arXiv :1606.01134 Bibcode :2016ApJS..225...15C ,doi :10.3847/0067-0049/225/1/15 S2CID 118438871 , 15. ^ van Belle, Gerard T. (March 2012). "Interferometric observations of rapidly rotating stars".The Astronomy and Astrophysics Review .20 (1): 51.arXiv :1204.2572 Bibcode :2012A&ARv..20...51V .doi :10.1007/s00159-012-0051-2 .S2CID 119273474 . ^ "* alf Oct" .SIMBAD Centre de données astronomiques de Strasbourg . RetrievedSeptember 4, 2008 .^ 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 . ^ 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 ^ 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 : 1289-1311.
