Alpha Columbae is a third magnitude star in the southern constellation of Columba. It has the proper name Phact (); Alpha Columbae is the Bayer designation, which is Latinized from α Columbae. This star has an apparent visual magnitude of 2.6, 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 .
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) derives from the Arabic فاختة fākhitah 'ring dove'. It was originally applied to the constellation Cygnus and later transferred to this star. The etymology of its name hadāri (unknown meaning) has also been suggested. In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN) to catalog and standardize proper names for stars. The WGSN's first bulletin of July 2016 included a table of the first two batches of names approved by the WGSN; which included Phact for this star.
In Chinese, (), meaning Grandfather, refers to an asterism consisting of α Columbae and ε Columbae. 中國星座神話, written by 陳久金. Published by 台灣書房出版有限公司, 2005, . Consequently, α Columbae itself is known as (, ). 香港太空館 - 研究資源 - 亮星中英對照表 , Hong Kong Space Museum. Accessed on line November 23, 2010. From this Chinese name, the name Chang Jin has appeared.
Properties This is believed to be a solitary star, although it has a faint optical companion at an angular separation of 13.5 arcseconds, making it a double star. The stellar classification of Alpha Columbae is B9Ve, 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. Like most if not all such stars, it is rotating rapidly with a projected rotational velocity of . The azimuthal equatorial velocity may be . It is a suspected Gamma Cassiopeiae type (GCAS) variable star, with its apparent magnitude varying from 2.62m to 2.66m.
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