Mu Columbae

μ Columbae
Location of μ Columbae (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Columba
Right ascension 05h 45m 59.89502s[1]
Declination −32° 18′ 23.1623″[1]
Apparent magnitude (V) 5.18[2]
Characteristics
Spectral type O9.5 V[3]
U−B color index −1.06[2]
B−V color index −0.28[2]
Variable type Suspected[4]
Astrometry
Radial velocity (Rv)+109.00 ± 1.8[5] km/s
Proper motion (μ) RA: +3.271 mas/yr[1]
Dec.: −22.176 mas/yr[1]
Parallax (π)1.7024 ± 0.0898 mas[1]
Distance1,894±111 ly
(581±34 pc)[6]
Absolute magnitude (MV)−3.78±0.11[6]
Details[6]
Mass18.9±0.3 M☉
Radius6.3±0.4 R☉
Luminosity43,650+4,210
−3,840 L☉
Surface gravity (log g)4.12±0.05 cgs
Temperature33,400±300 K
Rotational velocity (v sin i)125±8 km/s
Age2 – 4[7] Myr
Other designations
HR 1996, CD−32°2538, HD 38666, SAO 196149, HIP 27204
Database references
SIMBADdata

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.[8] The star is known to lie approximately 1,900 light years from the Solar System (with an error margin of a few hundred light years).[6]

This is a relatively fast rotating star that completes a full revolution approximately every 1.5 days. (Compare this to the Sun, which at only 22 percent 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.[9]

  1. ^ a b c d Cite error: The named reference DR3 was invoked but never defined (see the help page).
  2. ^ a b c Cite error: The named reference ducati was invoked but never defined (see the help page).
  3. ^ Cite error: The named reference gosss was invoked but never defined (see the help page).
  4. ^ Cite error: The named reference gcvs was invoked but never defined (see the help page).
  5. ^ Cite error: The named reference 0Ri12 was invoked but never defined (see the help page).
  6. ^ a b c d Cite error: The named reference quantitative was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference martins was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference Walker2017 was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference gualandris was invoked but never defined (see the help page).