Mu Columbae

From Wikipedia, the free encyclopedia
Jump to: navigation, search
Mu Columbae
Observation data
Epoch J2000      Equinox J2000
Constellation Columba
Right ascension 05h 45m 59.9s
Declination -32° 18′ 23″
Apparent magnitude (V) 5.15
Spectral type O9.5 V
U−B color index -1.06
B−V color index -0.28
Variable type Suspected
Radial velocity (Rv) +109.2 km/s
Proper motion (μ) RA: 3.01 mas/yr
Dec.: -22.62 mas/yr
Parallax (π) 2.52 ± 0.55 mas
Distance 1300 ly
(400 pc)
Absolute magnitude (MV) -2.84
Mass 12-15 M
Radius 4.5 R
Luminosity 23,300 L
Temperature 33,700 K
Metallicity ?
Rotation 1.5 days (~153 km/s.)
Age 2.7 × 106 years
Other designations
HR 1996, CD -32°2538, HD 38666, SAO 196149, HIP 27204.

Mu Columbae (μ Col, μ Columbae) is a star in the constellation of Columba. It is one of the few O-class stars that are visible to the unaided eye. The star is known to lie approximately 1,300 light years from our solar system (with an error margin of a few hundred light years).

This is a relatively fast rotating star that completes a full revolution approximately every 1.5 days. (Compare this to our Sun, which at only 22% of this star's diameter rotates only once every 25.4 days.) This rate of rotation is fairly typical for stars of this class.

Based on measurements of proper motion and radial velocity, astronomers know that this star and AE Aurigae are moving away from each other at a relative velocity of over 200 km/s. Their common point of origin intersects with Iota Orionis in the Trapezium cluster, some two and half million years in the past. The most likely scenario that could have created these runaway stars is a collision between two binary star systems, with the stars being ejected along different trajectories radial to the point of intersection.


In Chinese astronomy, Mu Columbae is called 屎, Pinyin: Shǐ, meaning Excrement, because this star is marking itself and stand alone in Excrement asterism, Three Stars mansion (see : Chinese constellation).[1] 屎 (Shǐ) westernized into She by R.H. Allen, with the meaning is "the Secretions" [2]

This star, along with ζ CMa, λ CMa, γ Col, δ Col, θ Col, κ Col, λ Col and ξ Col, were Al Ḳurūd (ألقرد - al-qird), the Apes.[3]


  • A. Blaauw & W.W. Morgan, 1954, "The Space Motions of AE Aurigae and mu Columbae with Respect to the Orion Nebula", Astrophysical Journal, v.119, p. 625.
  • R. Hoogerwerf, J.H.J. de Bruijne, P.T. de Zeeuw, 2000, "The origin of runaway stars", Astrophysical Journal, v.544, issue 2, pp. L133-L136.
  1. ^ (Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 15 日
  2. ^ Richard Hinckley Allen: Star Names — Their Lore and Meaning: Columbae
  3. ^ Davis Jr., G. A. (October 1944). "The Pronunciations, Derivations, and Meanings of a Selected List of Star Names". Popular Astronomy 18: 14. Bibcode:1944PA.....52....8D. 

External links[edit]