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
RadiusTemplate:Val[9] Template:Solar radius
Luminosity (bolometric)1,000[8] Template:Solar luminosity
Surface gravity (log g)Template:Val[9] cgs
TemperatureTemplate: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 Template: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

Template:Reflist Template:Stars of Columba

  1. ↑ a b c d e f Cite error: Invalid <ref> tag; no text was provided for refs named aaa474_2_653
  2. ↑ a b c d Cite error: Invalid <ref> tag; no text was provided for refs named mnassa31_69
  3. ↑ a b c Cite error: Invalid <ref> tag; no text was provided for refs named levenhagen_Leister_2006
  4. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named houk1979
  5. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named bsc1
  6. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named gcsrv
  7. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named Anderson2012
  8. ↑ a b Cite error: Invalid <ref> tag; no text was provided for refs named kaler
  9. ↑ a b c Cite error: Invalid <ref> tag; no text was provided for refs named arcos
  10. ↑ a b c Cite error: Invalid <ref> tag; no text was provided for refs named aaa489_2_627
  11. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named sb0
  12. ↑ Script error: No such module "citation/CS1".
  13. ↑ Script error: No such module "citation/CS1".
  14. ↑ a b Cite error: Invalid <ref> tag; no text was provided for refs named bsc2
  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. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named mnras389_2_869
  26. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named dommanget_nys2002
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