Alpha Columbae

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Template:Short description

Alpha Columbae
Template:Location mark
Location of α Columbae (circled)
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Columba
Right ascension Template:RA[1]
Declination Template:DEC[1]
Apparent magnitude (V) 2.645[2]
Characteristics
Spectral type B9Ve[3] or B7 IV[4]
U−B Template:Engvar −0.44[2]
B−V Template:Engvar −0.125[2]
R−I Template:Engvar −0.09[5]
Astrometry
Radial velocity (Rv)+35.0[6] km/s
Proper motion (μ) RA: −1.58[1] mas/yr
Dec.: −24.82[1] mas/yr
Parallax (π)12.48±0.36 mas[1]
DistanceTemplate:Rnd ± Template:Rnd ly
(Template:Rnd ± Template:Rnd pc)
Absolute magnitude (MV)−1.87[7]
Details
Mass4.5[8] Template:Solar mass
RadiusScript error: No such module "val".[9] Template:Solar radius
Luminosity (bolometric)1,000[8] Template:Solar luminosity
Surface gravity (log g)Script error: No such module "val".[9] cgs
TemperatureScript error: No such module "val".[9] K
Rotational velocity (v sin i)176[10] km/s
Age93[3] Myr
Metallicity [Fe/H]{{{metal_fe2}}} dex
Other designations
Template:Odlist[11]
Database references
SIMBADdata

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Alpha Columbae or α Columbae, officially named Phact (Template:IPAc-en),[12][13] is a third magnitude star in the southern constellation of Columba. It has an apparent visual magnitude of 2.6,[2] 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 Script error: No such module "convert"..[1]

Nomenclature

α Columbae, Latinized to Alpha Columbae, is the star's Bayer designation.

The traditional name of Phact (also rendered Phad, Phaet, Phakt)[14] derives from the Arabic فاختة fākhitah 'ring dove'. It was originally applied to the constellation Cygnus and later transferred to this star.[15][16][17][18] The etymology of its name hadāri (unknown meaning)[19] has also been suggested. In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN)[20] to catalog and standardize proper names for stars. The WGSN's first bulletin of July 2016[21] included a table of the first two batches of names approved by the WGSN; which included Phact for this star.

In Chinese, Script error: No such module "Lang". (Script error: No such module "Lang".), meaning Grandfather, refers to an asterism consisting of α Columbae and ε Columbae.[22] Consequently, α Columbae itself is known as Script error: No such module "Lang". (Script error: No such module "Lang"., Template:Langx.).[23] From this Chinese name, the name Chang Jin has appeared[24]

Properties

This is believed to be a solitary star,[10][25] although it has a faint optical companion at an angular separation of 13.5 arcseconds, making it a double star.[26] The stellar classification of Alpha Columbae is B9Ve,[3] 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.[14] 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.[10] It is a suspected Gamma Cassiopeiae type (GCAS) variable star, with its apparent magnitude varying from 2.62m to 2.66m.

References

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  1. ↑ a b c d e f Script error: No such module "citation/CS1".
  2. ↑ a b c d Script error: No such module "citation/CS1".
  3. ↑ a b c Script error: No such module "citation/CS1".
  4. ↑ Script error: No such module "citation/CS1".
  5. ↑ HR 1956, 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 April 21, 2009.
  6. ↑ Script error: No such module "Citation/CS1".
  7. ↑ Script error: No such module "citation/CS1".
  8. ↑ a b Jim Kaler: Phact - STARS Template:Webarchive. Accessed on line April 21, 2009.
  9. ↑ a b c Script error: No such module "Citation/CS1".
  10. ↑ a b c Script error: No such module "citation/CS1".
  11. ↑ Template:Cite simbad
  12. ↑ Script error: No such module "citation/CS1".
  13. ↑ Script error: No such module "citation/CS1".
  14. ↑ a b Note of HR 1956, 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 April 21, 2009.
  15. ↑ Script error: No such module "citation/CS1".
  16. ↑ Script error: No such module "citation/CS1".
  17. ↑ Script error: No such module "citation/CS1".
  18. ↑ Script error: No such module "citation/CS1".
  19. ↑ Script error: No such module "citation/CS1".
  20. ↑ Script error: No such module "citation/CS1".
  21. ↑ Script error: No such module "citation/CS1".
  22. ↑ Template:In lang 中國星座神話, written by 陳久金. Published by 台灣書房出版有限公司, 2005, Template:ISBN.
  23. ↑ Template:In lang 香港太空館 - 研究資源 - 亮星中英對照表 Template:Webarchive, Hong Kong Space Museum. Accessed on line November 23, 2010.
  24. ↑ Richard Hinckley Allen: Star Names — Their Lore and Meaning: Columbae
  25. ↑ Script error: No such module "Citation/CS1".
  26. ↑ CCDM J05396-3404, database entry, J. Dommanget and O. Nys (2002) Catalogue of the Components of Double and Multiple Stars, Accessed on line April 21, 2009.

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Template:Stars of Columba

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