Alpha Columbae

Alpha Columbae
Location of α Columbae (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Columba[1]
Right ascension 05h 39m 38.94103s[2]
Declination −34° 04′ 26.7950″[2]
Apparent magnitude (V) 2.645[3]
Characteristics
Spectral type B9Ve[4] or B7 IV[5]
U−B color index −0.44[3]
B−V color index −0.125[3]
R−I color index −0.09[6]
Variable type γ Cas?[7]
Astrometry
Radial velocity (Rv)+35.0[8] km/s
Proper motion (μ) RA: −1.58[2] mas/yr[2]
Dec.: −24.82 mas/yr[2]
Parallax (π)12.48±0.36 mas[2]
Distance261 ± 8 ly
(80 ± 2 pc)
Absolute magnitude (MV)−1.87[1]
Details
Mass4.5[9] M☉
Radius7±0.14[10] R☉
Luminosity3,311[11] L☉
Surface gravity (log g)3.5±0.04[10] cgs
Temperature12,200±122[10] K
Rotational velocity (v sin i)176[12] km/s
Age93[4] Myr
Other designations
Phact, α Col, NSV 2549, CD−34 2375, CPD−34 703, FK5 215, GC 7078, HD 37795, HIP 26634, HR 1956, SAO 196059, PPM 281732, CCDM  J05396−3404 A[13]
Database references
SIMBADdata

Alpha Columbae is a third magnitude star in the southern constellation of Columba. It has the proper name Phact (/ˈfækt/);[14][15] Alpha Columbae is the Bayer designation, which is Latinized from α Columbae. This star has an apparent visual magnitude of 2.6,[3] making it the brightest member of Columba. Based upon parallax measurements made during the Hipparcos mission, Alpha Columbae is located at a distance of around 261 light-years (80 parsecs).[2]

Nomenclature

α Columbae, Latinized to Alpha Columbae, is the star's Bayer designation. It is abbreviated Alpha Col or α Col.

The traditional name of Phact (also rendered Phad, Phaet, Phakt)[16] derives from the Arabic فاختة fākhitah 'ring dove'. It was originally applied to the constellation Cygnus and later transferred to this star.[17][18][19][20] The etymology of its name hadāri (unknown meaning)[21] has also been suggested. In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN)[22] to catalog and standardize proper names for stars. The WGSN's first bulletin of July 2016[23] included a table of the first two batches of names approved by the WGSN; which included Phact for this star.

In Chinese, 丈人 (Zhàng Rén), meaning Grandfather, refers to an asterism consisting of α Columbae and ε Columbae.[24] Consequently, α Columbae itself is known as 丈人一 (Zhàng Rén yī, English: the First Star of Grandfather).[25] From this Chinese name, the name Chang Jin has appeared.[26]

Properties

This is believed to be a solitary star,[12][27] although it has a faint optical companion at an angular separation of 13.5 arcseconds, making it a double star.[28] The stellar classification of Alpha Columbae is B9Ve,[4] matching a B-type main-sequence star. The spectrum shows it to be a Be star surrounded by a hot gaseous disk, which is generating emission lines because of hydrogen recombination.[16] Like most if not all such stars, it is rotating rapidly with a projected rotational velocity of 176 km s−1. The azimuthal equatorial velocity may be 457 km s−1.[12] It is a suspected Gamma Cassiopeiae type (GCAS) variable star, with its apparent magnitude varying from 2.62m to 2.66m.[7]

References

  1. ^ a b 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 XHIP record for this object at VizieR.
  2. ^ a b c d e f 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. S2CID 18759600.
  3. ^ a b c d Cousins, A. W. J. (1972). "UBV Photometry of Some Very Bright Stars". Monthly Notes of the Astronomical Society of Southern Africa. 31: 69. Bibcode:1972MNSSA..31...69C.
  4. ^ a b c Levenhagen, R. S.; Leister, N. V. (2006). "Spectroscopic analysis of southern B and Be stars". Monthly Notices of the Royal Astronomical Society. 371 (1): 252–262. arXiv:astro-ph/0606149. Bibcode:2006MNRAS.371..252L. doi:10.1111/j.1365-2966.2006.10655.x. S2CID 16492030.
  5. ^ Houk, Nancy (1979). Michigan catalogue of two-dimensional spectral types for the HD stars. Vol. 3. Ann Arbor, Michigan: Dept. of Astronomy, University of Michigan. Bibcode:1982mcts.book.....H.
  6. ^ Hoffleit, D.; Warren, Jr., W. H. "HR 1956 database entry". The Bright Star Catalogue (5th Revised Ed. (Preliminary Version) ed.). Retrieved 2009-04-21. CDS ID V/50
  7. ^ a b Samus, N. N.; et al. (2017). "General Catalogue of Variable Stars". Astronomy Reports. GCVS 5.1. 61 (1): 80–88. Bibcode:2017ARep...61...80S. doi:10.1134/S1063772917010085. S2CID 255195566.
  8. ^ Wilson, R. E. (1953). "General Catalogue of Stellar Radial Velocities". Carnegie Institute Washington D.C. Publication. Carnegie Institute of Washington D.C. Bibcode:1953GCRV..C......0W.
  9. ^ Kaler, James B. "Phact". STARS. Retrieved 2026-05-17.
  10. ^ a b c Arcos, C.; et al. (January 3, 2018). "Stellar parameters and H α line profile variability of Be stars in the BeSOS survey". Monthly Notices of the Royal Astronomical Society. 474 (4): 5287–5299. arXiv:1711.08675. Bibcode:2018MNRAS.474.5287A. doi:10.1093/mnras/stx3075. ISSN 0035-8711.
  11. ^ Balona, Luis A.; Ozuyar, Dogus (2021). "TESS Observations of be Stars: General Characteristics and the Impulsive Magnetic Rotator Model". The Astrophysical Journal. 921 (1): 5. arXiv:2008.06288. Bibcode:2021ApJ...921....5B. doi:10.3847/1538-4357/ac1a77.
  12. ^ a b c Oudmaijer, R. D.; et al. (October 2008). "Sub-milliarcsecond precision spectro-astrometry of Be stars". Astronomy and Astrophysics. 489 (2): 627–631. arXiv:0807.3673. Bibcode:2008A&A...489..627O. doi:10.1051/0004-6361:20079117. S2CID 10317142.
  13. ^ "alf Col". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved April 21, 2009.
  14. ^ Kunitzsch, Paul; Smart, Tim (2006). A Dictionary of Modern star Names: A Short Guide to 254 Star Names and Their Derivations (2nd rev. ed.). Cambridge, Massachusetts: Sky Pub. ISBN 978-1-931559-44-7.
  15. ^ Mamajek, Eric. "IAU Catalog of Star Names". University of Rochester. Retrieved 28 July 2016.
  16. ^ a b Hoffleit, D.; Warren, Jr., W. H. "Note of HR 1956 database entry". The Bright Star Catalogue (5th Revised Ed. (Preliminary Version) ed.). Retrieved 2009-04-21. CDS ID V/50
  17. ^ Davis, Jr., G. A. (1971). Pronunciations, Derivations, and Meanings of a Selected List of Star Names (Reprint ed.). Cambridge, MA: Sky Publishing Corp. p. 11.
  18. ^ Kunitzsch, P. (1959). Arabische Sternnamen in Europa. Wiesbaden: Otto Harrassowitz. pp. 191–192.
  19. ^ Laffitte, R. (2005). Héritages arabes: Des noms arabes pour les étoiles (2éme revue et corrigée ed.). Paris: Librairie Orientaliste Paul Geunthner / Les Cahiers de l'Orient. p. 223.
  20. ^ Kunitzsch, P.; Smart, T. (2006). A Dictionary of Modern star Names: A Short Guide to 254 Star Names and Their Derivations (2nd rev. ed.). Cambridge, MA: Sky Pub. p. 30. ISBN 978-1-931559-44-7.
  21. ^ Allen, R. H. (1963). Star Names: Their Lore and Meaning (Reprint ed.). New York, NY: Dover Publications Inc. p. 167. Retrieved 2026-05-17. ISBN 0-486-21079-0.
  22. ^ "IAU Working Group on Star Names (WGSN)". International Astronomical Union. Archived from the original on 10 June 2016. Retrieved 22 May 2016.
  23. ^ Mamajek, Eric. "Bulletin of the IAU Working Group on Star Names, No. 1" (PDF). University of Rochester. Retrieved 28 July 2016.
  24. ^ (in Chinese) 中國星座神話, written by 陳久金. Published by 台灣書房出版有限公司, 2005, ISBN 978-986-7332-25-7.
  25. ^ (in Chinese) 香港太空館 - 研究資源 - 亮星中英對照表 Archived 2011-01-30 at the Wayback Machine, Hong Kong Space Museum. Accessed on line November 23, 2010.
  26. ^ Allen, Richard Hinckley. "Columbae". Star Names — Their Lore and Meaning. Retrieved 2026-05-17.
  27. ^ 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.
  28. ^ Dommanget, J.; Nys, O. (2002). "CCDM J05396-3404 database entry". Catalogue of the Components of Double and Multiple Stars. Retrieved 2009-04-21.
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