Alpha Octantis
Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
---|---|
Constellation | Octans |
Right ascension | 21h 04m 43.06347s[1] |
Declination | −77° 01′ 25.5735″[1] |
Apparent magnitude (V) | 5.13[2] |
Characteristics | |
Spectral type | F4III + F5III (spectroscopic binary)[3] |
U−B color index | +0.13[4] |
B−V color index | +0.490±0.008[2] |
Variable type | EB[5] |
Astrometry | |
Radial velocity (Rv) | 85.9±1.5[2] km/s |
Proper motion (μ) | RA: +22.5215[1] mas/yr Dec.: −369.325[1] mas/yr |
Parallax (π) | 22.5215 ± 0.0955[1] mas |
Distance | 144.8 ± 0.6 ly (44.4 ± 0.2 pc) |
Absolute magnitude (MV) | 1.93±0.02[6] |
Orbit[3] | |
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 | |
Mass | 1.42[7] M☉ |
Radius | 3.69[8] R☉ |
Temperature | 6,270[6] K |
Metallicity [Fe/H] | 0.07[6] dex |
Rotational velocity (v sin i) | 85[9] km/s |
Age | 1.5±0.1[6] Gyr |
Other designations | |
Database references | |
SIMBAD | data |
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 Johann Bayer in his star atlas Uranometria, 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.[2] 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 giant stars, each with spectral type F, orbiting each other with a period of just over 9 days and an eccentricity of 0.39.[3] The pair form a Beta Lyrae-type eclipsing binary system, dropping by magnitude 0.04 during the primary eclipse.[5] 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 two debris disks; the first has a temperature of 450 K and is orbiting at a distance of 1.40 AU from its host star, while the second is a much cooler 40 K and orbits 187.8 AU from the system.[8]
References[]
- ^ 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.
- ^ 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 ID V/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
- ^ a b 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. Retrieved September 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.
External links[]
- Alpha Octantis, Jim Kaler, Stars.
- F-type giants
- Spectroscopic binaries
- Circumstellar disks
- Beta Lyrae variables
- Octans
- Bayer objects
- Durchmusterung objects
- Henry Draper Catalogue objects
- Hipparcos objects
- HR objects