Omega Fornacis

Omega Fornacis, which is Latinized from ω Fornacis, is a wide binary star[11] system in the southern constellation of Fornax. It has a blue-white hue and is faintly visible to the naked eye as a fifth-magnitude star.[6] The system lies at a distance of approximately 470 light years from the Sun based on parallax,[1] and is drifting further away with a radial velocity of +10 km/s.[6]

Omega Fornacis
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Fornax
Right ascension  2h 33m 50.70081s[1]
Declination –28° 13′ 56.3890″[1]
Apparent magnitude (V) 4.95 + 7.71[2]
Characteristics
A
Evolutionary stage main sequence[3]
Spectral type B9V[4]
U−B color index −0.13[5]
B−V color index −0.050±0.007[6]
R−I color index −0.07[5]
B
Spectral type A3V[7]
U−B color index +0.09[8]
B−V color index +0.17[8]
Astrometry
Radial velocity (Rv)+9.7±2.8[6] km/s
Proper motion (μ) RA: −13.290±0.243[1] mas/yr
Dec.: −5.532±0.305[1] mas/yr
Parallax (π)7.0025 ± 0.1527[1] mas
Distance470 ± 10 ly
(143 ± 3 pc)
Absolute magnitude (MV)-0.87[6]
Details
A
Mass3.42±0.11[3] M☉
Radius2.81[7] R☉
Luminosity268+72
−57[3] L☉
Temperature10,910±420[9] K
Rotational velocity (v sin i)85±13[7] km/s
B
Radius2.2[7] R☉
Rotational velocity (v sin i)180±29[7] km/s
Other designations
ω For, CD–28°819, HD 16046, HIP 11918, HR 749, SAO 167882, CCDM J02338-2814AB, WDS J02338-2814[10]
Database references
SIMBADdata

The dual nature of this system was discovered in 1836 by John Herschel. As of 2013, the two components had an angular separation of 11.0″ along a position angle of 246°.[2] This corresponds to a projected separation of 1,520 AU.[7]

The magnitude 4.95[2] primary, designated component A, is a chemically peculiar[3] B-type main-sequence star with a stellar classification of B9V[4] It has 3.4[3] times the Sun's mass and is radiating around 268[3] times the luminosity of the Sun from its photosphere at an effective temperature of 10,910 K.[9] Component B, the magnitude 7.71[2] secondary, is an A-type main-sequence star with a class of A3V.[7] It is smaller than the primary, but has a higher projected rotational velocity.[7]

References
  1. 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.
  2. Mason, B. D.; et al. (2014), The Washington Visual Double Star Catalog, Bibcode:2001AJ....122.3466M, doi:10.1086/323920, retrieved 2015-07-22
  3. Zorec, J.; Royer, F. (January 2012), "Rotational velocities of A-type stars. IV. Evolution of rotational velocities", Astronomy & Astrophysics, 537: A120, arXiv:1201.2052, Bibcode:2012A&A...537A.120Z, doi:10.1051/0004-6361/201117691.
  4. Houk, Nancy (1979). "Michigan catalogue of two-dimensional spectral types for the HD stars". 3. Ann Arbor, Michigan: Dept. of Astronomy, University of Michigan. Bibcode:1982mcts.book.....H. Cite journal requires |journal= (help)
  5. Hoffleit, D.; Warren, Jr., W. H. (1991). "VizieR Detailed Page". Bright Star Catalogue (5th Revised ed.). CDS. Retrieved 2012-07-13.
  6. 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.
  7. Howe, K. S.; Clarke, C. J. (January 2009). "An analysis of v sin (i) correlations in early-type binaries". Monthly Notices of the Royal Astronomical Society. 392 (1): 448–454. Bibcode:2009MNRAS.392..448H. doi:10.1111/j.1365-2966.2008.14073.x.
  8. Corbally, C. J. (1984). "Close visual binaries. I - MK classifications". Astrophysical Journal Supplement Series. 55: 657. Bibcode:1984ApJS...55..657C. doi:10.1086/190973.
  9. Zorec, J.; et al. (2009). "Fundamental parameters of B supergiants from the BCD system. I. Calibration of the (λ_1, D) parameters into Teff". Astronomy and Astrophysics. 501 (1): 297–320. arXiv:0903.5134. Bibcode:2009A&A...501..297Z. doi:10.1051/0004-6361/200811147.
  10. "ome For". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-10-29.
  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.Vizier catalog entry
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